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AfiRICULTORAL ENTOMOLOGY 
 
 FOR STUDENTS, FARMERS, FRUIT-GROWERS 
 AND GARDENERS 
 
 BY 
 
 HERBERT OSBORN, B.Sc, M.Sc. 
 
 PROFESSOR OF ZOOLOGY AND ENTOMOLOGY IN THE OHIO STATE UNIVERSITY, 
 
 COLUMBUS, OHIO, AND DIRECTOR OF THE LAKE LABORATORY, 
 
 CEDAR POINT, OHIO. 
 
 ILLUSTRATED WITH 252 ENGRAVINGS AND A COLORED PLATE 
 
 LEA & FEBIGER 
 
 PHILADELPHIA AND NEW YORK 
 1916 
 
.0^ 
 
 Entered according to the Act of Congress, in the year 1916, by 
 
 LEA & FEBIGER, 
 in the Office of the Librarian of Congress. All rights reserved. 
 
 APR 25 1916 
 
 kl,A428C96 
 
PREFACE 
 
 This book is designed to meet the needs of students and 
 others who wish to learn something of insect life especially 
 in relation to farm crops and livestock. The author assumes 
 that the students who read it will have had some training 
 in general biology and will have the guidance of teachers 
 familiar with the subject in connection with adequate labor- 
 atory facilities and opportunities for field studies. The 
 details of laboratory and field studies have not been included 
 since these are easily supplied by the teacher. For those 
 making individual studies there are many available books 
 covering the technic of entomological work. A glossary 
 has been included which covers the subject as presented in 
 these pages and in most of the reports and bulletins that are 
 likely to be consulted by the average student. 
 
 In order to make the scope of the book adequate it has 
 been necessary to condense the matter to the most essential 
 details, and to omit much that has value but which is not 
 absolutely indispensable to the presentation of the important 
 principles that concern the practice of economic entomology. 
 
 The author acknowledges his indebtedness to many 
 sources of information which are too numerous to mention 
 individually, but he is especially indebted to Dr. Howard, 
 of the Bureau of Entomology, for the privilege of using the 
 illustrations secured from his office and for suggestions; to 
 
iv PREFACE 
 
 Professors Washburn and Bruner for the loan of plates; 
 to the Iowa Experiment Station for use of figures, and the 
 Ohio Experiment Station for a number of photographs for 
 original use here. Professors Hine, INIetcalf, Barrows, 
 Mr. Kostir and Mr. Drake have assisted in reading manu- 
 script and proof and have generously given the author 
 the use of photographs and drawings. 
 
 H. O. 
 Columbus, Ohio, 1916. 
 
CONTENTS. 
 
 CHAPTER I. 
 Introduction 17 
 
 CHAPTER II. 
 
 Class Arachnida 22 
 
 CHAPTER III. 
 
 The Six-footed Insects 38 
 
 CHAPTER IV. 
 Lower Pterygota 51 
 
 CHAPTER V. 
 Order Hemiptera 93 
 
 CHAPTER VI. 
 Neuroptera and Allies 165 
 
 CHAPTER VII. 
 Coleoptera. Beetles . 172 
 
 CHAPTER VIII. 
 
 Lepidoptera 206 
 
 CHAPTER IX. 
 Order Diptera 248 
 
 CHAPTER X. 
 Bees and Wasps 291 
 
 CHAPTER XI. 
 
 Principles of Economic Entomology 312 
 
 Glossary 329 
 
 Index •. . 339 
 
AGMCULTUML ENTOMOLOGY 
 
 CHAPTER I. 
 INTRODUCTION. 
 
 The recent rapid growth in the subject of Agricultural 
 Entomology makes it a difficult matter to bring together 
 a comprehensive statement that will cover all of its different 
 phases in a thorough manner. Some idea of its growth 
 may be indicated by the fact that instead of a single ento- 
 mologist employed in the United States Department of 
 Agriculture, as was the case forty years ago, there are now 
 several hundred who are devoting their entire time to the 
 investigation of entomological problems, practically all of 
 which are related to agriculture. 
 
 A similar development of this work has taken place in 
 the State Experiment Stations, and there are also State 
 Entomological departments working in almost every State, 
 and in many of them two or three different organizations, 
 each with a large quota of workers. 
 
 Economic entomology in its wider sense covers all those 
 phases of the subject which have to do with insects of 
 importance in relation to mankind. The forms which 
 have distinctly agricultural relation are so numerous and 
 represent so completely all the different groups of insects 
 that we are compelled to include a very general survey of 
 the subject. 
 
 Some idea of the size of the group of insects and of its 
 place in biological study may be secured from the statement 
 2 ^ (17) 
 
18 INTRODUCTION 
 
 that there are now known and have been scientifically recog- 
 nized and described something over three hundred thousand 
 species of insects, a number which far surpasses that of all 
 other groups of animals together. Furthermore, the immense 
 numbers of individuals in each species and the great facility 
 which they possess for migration and rapidity of increase 
 make them a very dominant group of animals. 
 
 Not all insects, to be sure, have a direct importance to 
 mankind, but there is so large a number that are very 
 directly related to human interests in the way of destruction 
 of property or menace to health that it is unnecessary to 
 emphasize their importance. Many estimates have been 
 attempted of the extent of loss of crops, livestock, forests, 
 agricultural products, etc., and while none of these can be 
 considered exact, it is increasingly evident that such estimates 
 are conservative and in many cases the loss is greater than 
 is recognized. One of the current estimates is that about 
 10 per cent, of the aggregate of farm crops in the United 
 States is lost by insect attack, and if this be taken as an 
 approximate proportion there is something like one billion 
 dollars to be counted an economic loss from this source 
 each year. 
 
 It must be admitted that the entomologist has not been 
 able as yet to solve all of the problems of insect control. 
 There will doubtless be many cases where a practical control 
 of insects may not be reached for many years, but for a 
 considerable number of the most common and serious pests 
 it has been possible to discover methods by which a very 
 large proportion of the loss can be prevented. One phase 
 of entomological work, therefore, is the demonstration of 
 these possibilities in order to secure a general adoption of 
 control measures that have been proved successful. 
 
 While it is manifestly impossible to include in a small 
 book any full discussion of the many phases of entomology, 
 it is the purpose of this work to present a basis for the under- 
 standing of field observations, and especially for the under- 
 standing of the many articles relating to economic insects 
 which are now appearing in Government and State pub- 
 
INTRODUCTION 19 
 
 lications. Many of these publications are available and will 
 be found to contain an immense store of information, much 
 of it of very practical value, but its greatest utility will be 
 found to rest upon some acquaintance with the general 
 facts of insect life and insect habits. These are so dependent 
 upon certain conditions of structure ajid development that 
 acquaintance with some of the fundamental biological 
 features of insect life are essential to the most effective 
 utilization. 
 
 Formerly all of the arthropods, that is, all animals with 
 jointed bodies and jointed appendages, were grouped under 
 the head of insects, and even yet this term has a pretty 
 wide application in popular usage, although it is seldom 
 used now to cover as wide a range as formerly. The Arth- 
 ropods, as a whole, include crustaceans, myriapods, arach- 
 nids, hexapods, or six-footed insects, and of these the air- 
 breathing forms, all except the crustaceans, are still quite 
 commonly treated as insects. 
 
 The Onychophora is a tropical group including peripatus, 
 the most primitive of tracheate animals, and would on this 
 basis be considered as falling next to the Crustacea. 
 
 The most generalized next to these, the myriapods, might 
 be counted as possessing the greater number of insect-like 
 characters. This group, however, does not include any 
 forms that possess wings, but in the matter of antennae and 
 the tracheal respiration they are closely associated with 
 insects. The members of this group are, for the most part, 
 of comparatively little economic importance. A few of the 
 species included in the group of centipedes (Ckilopoda) are 
 poisonous, and in tropical countries are of some importance 
 on this account. The few species that occur in temperate 
 regions have little importance except as they may feed upon 
 other insects which occur under the litter at the surface of 
 the ground. 
 
 One species, the house centipede, a peculiar long-legged 
 creature, w^hich is occasionally found in cellars or around 
 houses, usually where there is some dampness, is, however, 
 of a certain amount of importance because of its feeding 
 
2U 
 
 INTRODUCTION 
 
 111)011 insects, and is looked ii})on as rather servieeahle in the 
 destruction of flies. It is a quite ungainly looking creature, 
 
 Fig. 1. — Scutigera forceps: Adult — natural size. (From Marlatt, 
 Div. Ent., U, S. Dept. Ag.) 
 
 with slender, flattened body, extremely long legs, and an 
 apparent duplication of anterior and posterior ends. 
 The millipedes (Diplopoda) are nearly cylindrical in 
 
INTRODUCTION 21 
 
 shape, are recognized as having two pairs of legs to each 
 apparent segment and there is usually a large number of 
 segments, 40 to 100 or more, so that the name thousand- 
 
 " 
 
 
 ^^"--■-. 
 
 ! / 
 
 
 
 
 \ 
 
 '• V ■ 
 
 
 
 \^ 
 
 y^ 
 
 ' ^ -■* ." 
 
 
 
 
 / 
 
 
 
 Fig. 2. — Scutigera forceps: a, newly hatched individual; 6, one of the 
 legs of same; c, terminal segment of body showing undeveloped legs coiled 
 up within — all enlarged. (After Marlatt. Div. Ent., U, S. Dept. Ag.) 
 
 legged worm is fairly descriptive. Most of these species 
 are found in moist places and feed upon vegetable debris, 
 but a few have been recorded as attacking vegetation, and 
 one species has been credited with injuring seed corn. 
 
CHAPTER II. 
 CLASS ARACHNIDA. 
 
 In the strict technical sense the group Arachnida may be 
 excluded from the Insecta, but in general usage, and to a 
 large extent in entomological practice, these divisions are 
 put together, and it seems desirable that the group should 
 be given a place in any work dealing with the insects in 
 general. 
 
 The group Arachnida includes spiders, scorpions, harvest- 
 men, mites, ticks, etc., and is characterized by the presence 
 of four pairs of legs, the absence of antennae and compound 
 eyes, and the lack of distinct metamorphosis, although 
 in certain groups there is a considerable change from the 
 newly hatched or six-legged form to the mature eight-legged 
 stage. 
 
 In general structure the Arachnida agree with other 
 Arthropoda, but the head and thorax are usually merged 
 into a cephalothorax separated from the abdomen by a 
 more or less distinct stalk; in the Acarina, however, this 
 separation is not marked and the body is without distinct 
 separation of head, thorax, and abdomen. 
 
 The economic importance of the group depends upon 
 their attacks upon certain crops, from the fact that many 
 of the species, such as spiders and harvestmen, are uniformly 
 predaceous and serve as important checks upon injurious 
 species; while other forms, such as the mites and ticks, are 
 parasitic upon domestic animals and man, and some of the 
 species occupy a most important relationship as carriers 
 of infectious diseases. 
 
 The subdivisions of the group are, for the most part, very 
 well marked and represent ancient groups which have 
 diverged quite widely from each other. 
 
 The scorpions (Scorpionida), mostly tropical in distribu- 
 (22) 
 
CLASS ARACHNIDA 23 
 
 tion, are represented by fossils in early geological times, 
 and are noted as possessing poison glands. They are recog- 
 nized by the broad cephalothorax, a division of the abdomen 
 into two portions, an anterior preabdomen of seven seg- 
 ments, and a slender hinder postabdomen of six segments, 
 on the last one of which there is a large poison gland and 
 sting. The sting is distinctly venomous and fatal to insects 
 or smaller animals, but seldom serious in its effect on the 
 human species. 
 
 The Pseudoscorpionida are minute forms resembling 
 scorpions in the width of the body and the long pedipalps, 
 but have no postabdomen or sting. They occur somewhat 
 commonly under bark or decaying logs or occasionally in old 
 papers or books, where they may secure book lice as food. 
 
 The Pedipalpi, or whip scorpions, have a tropical or 
 subtropical distribution and differ from the preceding groups 
 in the presence of a long, slender bristle or whip extending 
 from the hinder abdominal segment. 
 
 In the group Solpugida there is an exceptional separation 
 of head and thorax and the abdomen is distinctly segmented, 
 while the chelicerse are greatly enlarged and strongly chelate. 
 These are not only largely tropical, but are particularly 
 characteristic of arid regions. One species occurs in the 
 Rocky Mountain region as far north as Colorado. They 
 are carnivorous in habit, but not of particular economic 
 importance, as they occur usually in small numbers and in 
 locations which do not offer opportunity to capture espe- 
 cially injurious insects. 
 
 The Phalangida, or harvestmen, often called "daddy- 
 longlegs," are somewhat large and resemble spiders in 
 appearance, but the abdomen is not distinctly separated 
 from the thorax and the legs are in most species extremely 
 long. They feed on insects, especially on flies and other 
 small forms, and are to be counted as distinctly beneficial. 
 On account of a strong pungent odor they are disagreeable 
 to handle, but their presence in gardens and other places 
 where insects abound may be considered as distinctly desir- 
 able. 
 
24 
 
 CLASS ARACHNIDA 
 
 Order ARANEIDA. 
 
 This jijroii]) includes tlie familiar s])i(lers which are very 
 generally distributed over tlie world, and occupy a rather 
 conspicuous place among other animals. Their body is 
 sharply divided into cei)hal()th()rax and abdomen, and the 
 four pairs of legs are usually nearly equal in length. The 
 
 Fig. .3. — Epeira scolopetaria, showdng normal position of spider in web 
 head downward. A vibrator at x agitating the web will cause the spider 
 to rush at once to point of contact. (Photo by Prof. W, M. Barrows.) 
 
 eyes are simple and usually eight in number, and the large 
 mandibles are attached at right angles to the axis of the 
 body. In some species these are provided with a poison 
 duct. The })ite is venomous to smaller organisms, and in 
 some of the larger, like the tarantula, the bite is a serious 
 matter for man. Spiders oft'er a great many attractive 
 
ORDER ACARINA 
 
 25 
 
 features, particularly in their web-making habit and in their 
 adaptation for the capture of prey. They are distinctly 
 carnivorous in habit and may be considered useful, since 
 the majority of them capture insects, and the kinds of 
 insects captured are quite generally such as are detrimental 
 to man. In general, therefore, spiders should be left unmo- 
 lested and their insect-feeding habits utilized in the reduc- 
 tion of injurious insects. 
 
 Fig. 4. — The common red spider (Tetranychus bimaculatus) : a, adult; 
 b, palpus; c, claws; a, greatly enlarged; h, c, still more enlarged. (After 
 Banks. From Bur. Ent., U. S. Dept. Ag.) 
 
 Order ACARINA. 
 
 These are commonly known as mites, ticks, scab insects, 
 mange insects, etc., and are in general distinguished by 
 having no prominent separation between the different 
 regions of the body, the head, thorax, and abdomen, forming 
 one closely connected structure. They have eight legs, 
 except in the early stages, when there are but six; the 
 eyes are often small or obsolete, the spiracles reduced to 
 one pair, sometimes apparently wanting; the mouth parts 
 
26 
 
 CLASS ARACHNIDA 
 
 are fitted for piercing, biting, or in some cases for combined 
 biting and suction, there being usually a pair of slender, 
 sharp mandibles capable of penetrating the skin of the 
 host animals. Much variation of habit exists, and ranges 
 from free forms to strictly parasitic forms. 
 
 Fig. 5 — Tetranychus gloveri: Adult — much enlarged. (Titus, Div. 
 Ent., U. S. Dept. Ag.) 
 
 Harvest Mites; Chiggers. 
 
 In the family TromhidiidoB, which includes normally plant- 
 feeding species, we find a few species which have adopted 
 a phase of parasitism which, though apparently abnormal, 
 results in extreme annoyance to the animals affected. 
 
 Apparently the most abundant species in this country 
 is the Leptus irritans of Riley, which is illustrated herewith. 
 This occurs in a large portion of the United States, and 
 occasions during the summer months an enormous amount 
 of suffering. It ranges north in the Mississippi Valley into 
 
ORDER ACARINA 27 
 
 central Iowa, at least, and in Ohio to Lake Erie, appearing 
 by the latter part of June or fore part of July, but becoming 
 especially annoying during August. In the latitude of 
 Washington it is very abundant early in June, and farther 
 south its season extends until, in southern Mexico, what 
 is apparently the same species is abundant and equally 
 annoying in January. 
 
 The form in which this pest is observed usually is the 
 larval or six-legged form. It is nearly circular in outline, 
 the legs extending well beyond the margins of the body, 
 of a bright red color, and so minute that it is only with 
 the closest scrutiny that it can be detected. 
 
 Fig. 6. — Leptus irritans to the right and americana to the left. (From 
 
 Riley.) 
 
 It is brushed from the leaves of various plants on to the 
 hands or clothing of people and to the bodies of other animals, 
 and the mite then proceeds to burrow into the skin, not- 
 withstanding the fact that, so far as all evidence shows, 
 this proceeding is absolutely fatal to it and prevents any 
 possibility of its maturing or producing eggs. 
 
 There is great difference in the susceptibility shown by 
 different persons to the attacks of this mite, some not 
 seeming to be affected seriously by them, while others must 
 submit to extreme torture every time they happen to become 
 attacked by them, even if but few in number. 
 
28 CLASS ARACHNIDA 
 
 As the mites are invariably secured })y working among 
 raspberries, currants, or other sln-ub})ery wliicli luirbors 
 them, or by walkin^^ in grass or low herbage wliere they 
 occur, sometimes even by sitting or lying for a short time 
 upon grass or clover, it is evident that the best precaution 
 for suscej^tible ])ersons is to avoid all such ex])osure. When 
 such avoidance is impracticable, the clothing may be made 
 to fit closely at the wrists and ankles, and then as soon as 
 possible after having been exposed to the mites make an 
 entire change of clothing, bathe in hot, soapy water, and 
 if any indications of mites are present, wash the affected ])arts 
 with diluted carbolic acid, 1 part to 50 or 100 parts water. 
 
 In the tropics rum or w^hisky is recommended as a wash, 
 and diluted alcohol can be used with good results. 
 
 With a little pains it is possible to locate the mites, as 
 they may be found before they have completely buried 
 themselves in the skin in the centre of the little red swelling 
 that has been raised by their preliminary irritation, and if 
 they are removed at this stage, instead of being allowed to 
 bury themselves in the skin the subsequent inflammation 
 and itching will be largely prevented. 
 
 Family Gamasidse. — The family Gamasidce contains a 
 large number of small mites, most of them being free or 
 semiparasitic in habit. 
 
 A large number occur as parasites on various species of 
 insects, but the two species to be mentioned here occur on 
 birds, and are sometimes very troublesome. 
 
 The Bird Tick (Dermanyssiis avium). — The bird tick is a 
 very familiar form to keepers of cage birds, and is known in 
 many places as the red mite. It occurs on a great variety 
 of birds, and has sometimes been considered to embrace 
 the chicken tick, mention of which follows, but that is 
 now generally conceded to represent a distinct form. The 
 mites are easily seen with the naked eye and appear as 
 animated red specks running over the bodies of birds, or 
 on the perches, bars of cages, etc. The eggs are laid in 
 cracks or corners of the cage, where may be found also the 
 molted skins and often numerous young and old mites. 
 
ORDER ACARINA 
 
 29 
 
 The attacks on the birds are made probably for the 
 most part at night, but the mites are usually well filled 
 with blood, which gives them their red color. 
 
 The use of perches that are solid, smooth, and free from 
 cracks, and the frequent dipping of these in hot water, and 
 the thorough cleansing of the entire cage, using boiling water 
 if there are inaccessible cracks, will serve to destroy the 
 pests. 
 
 Fig. 7. — Poultry tick (Dermanyssus gallince): a, adult; 6, tarsus; c, 
 mouth parts; d and e, young — all enlarged. (After Osborn, Bur. Ent., U. 
 S. Dept. Ag.) 
 
 The Poultry Tick {Dermanyssus (jalUfKp). ^One of the 
 most persistent and injurious of the pests of the hennery 
 is the little chicken mite, which gathers on the fowls, espe- 
 cially at night, and sucks their blood. It is a well-known 
 form, and has been described for many years, though in 
 many works it is confused with the preceding species or 
 considered simply a variety of that form. Its distribution 
 seems to extend pretty generally over the world where 
 domestic fowls are kept. 
 
30 CLASS ARACHNIDA 
 
 The full-grown mites are about 1 mm. long, of a light 
 gray or wliitish color, with dark patches showing through 
 the skin, but when full fed have a distinct red color. They 
 swarm in cracks and corners of the henhouse, and often 
 when numerous, over all surrounding objects, and at such 
 time are liable to become a great pest to man and such other 
 animals as they may get access to. 
 
 The dust bath is considered of use in checking this pest, 
 but when there is a general infestation, the best plan will 
 be found to clear the house, then spray well with kerosene 
 or kerosene emulsion, taking pains to reach the cracks; 
 thoroughly drench the roosts with hot water or kerosene, 
 benzine, or gasoline, whitewash the house, or dust with 
 carbolated lime, and then daub the ends of the roosts, where 
 they come in contact with supports, with coal tar, so the 
 mites w^ould have to cross it to reach the fowls. 
 
 Family Ixodidae. — This family includes forms known 
 commonly as ticks, and familiar examples are the dog tick 
 or wood tick, frequently found upon domestic animals, 
 and other examples are the cattle tick of the Southern States 
 and spotted fever tick of the Rocky Mountain region. In 
 this group the body is robust and becomes much distended 
 in the female when the eggs are developed. The mouth 
 parts are adapted for puncturing the skin of host animals, 
 and the species generally attach themselves to warm-blooded 
 animals as 'a part of the life-cycle, and in some cases this 
 attachment is permanent, while in others it is temporary 
 and the individual tick may occupy several different hosts 
 in the course of its life-cycle. 
 
 The family is of particular importance because of the 
 fact that some of the species are carriers of important 
 diseases, most notable of which is Texas fever, transmitted 
 by the cattle tick. The spotted fever tick is the carrier of 
 spotted fever. 
 
 The Pigeon Tick {Argas reflexus). — The pigeon tick is a 
 common species on pigeons found mainly in pigeon houses, 
 and sucks the blood of pigeons for its nutriment. It is, 
 however, able to survive for long periods without food, 
 
ORDER ACARINA 
 
 31 
 
 some recorded instances are of individuals kept in confine- 
 ment for two years without food, but which moulted at 
 frequent intervals. 
 
 The related Argas persicus occurs both in the old world 
 and America. It is a troublesome pest for chickens and is 
 credited also with attacks on human beings. 
 
 Fig. 8. 
 
 -Argas miniatus, a tick which infests poultry. Greatly enlarged. 
 (Banks, Div. Ent., U. S. Dept. Ag.) 
 
 The Cattle Tick (Margaropus annulatus). — The cattle tick, 
 as already mentioned, has received probably more atten- 
 tion than any other species, as it has been known for many 
 years as the carrier of Texas fever in cattle, and its great 
 importance to the cattle industry has been the occasion 
 for elaborate studies regarding its habits. In this species 
 the newly hatched tick locates as soon as possible upon 
 a warm-blooded animal, preferably upon cattle, as these 
 seem to be by all means the preferred host. Once located 
 they retain their attachment until mature. The females 
 when mature and gorged with eggs loosen their hold, drop 
 to the ground and eggs may be distributed wherever the 
 adults fall. The period of incubation differs greatly, with 
 regard to temperature, so that the rate of development and 
 number of generations differ much at different seasons of 
 
32 CLASS ARACHNIDA 
 
 the year. An important fact concerning tlie transfer of 
 disease is that tlie protozoa in the diseased animal are taken 
 into the l)ody of the tick, and within tlie body of this host 
 may enter the eggs, so that young ticks that have never fed 
 upon an animal may serve to introduce the parasite in an 
 individual that has not previously had the disease. 
 
 Elimination of ticks from the cattle and prevention of 
 their attacks therefore become essential factors in the 
 eradication of Texas fever. To accomplish the eradica- 
 tion of the ticks in any given locality it is necessary to 
 rotate animals from one field to another, allowing time for 
 hatching of eggs and dying of the ticks before the field again 
 is used as a pasture for cattle. Working upon this basis, 
 considerable areas in the Southern States are now con- 
 sidered tick-free and the hope is that the quarantine line 
 will be pushed farther and farther south until ultimately 
 the ticks and associated disease may be completely eradi- 
 cated. Certain districts in Tennessee and North Carolina 
 are now considered tick-free and released from quarantine 
 restrictions. 
 
 The Spotted Fever Tick {Dermacentor wnvsta). — The 
 spotted fever tick has come into great prominence in recent 
 years because of the determination that it serves as the 
 carrier of the much-dreaded spotted fever. This disease 
 has caused many deaths in Montana and adjacent States, 
 and the rate of mortality for individuals attacked is very 
 high, so that its appearance is very much dreaded. 
 
 It has been shown that this disease is carried by this 
 particular species of tick, and in no other way. It differs 
 in habit from the cattle tick in that a number of different 
 hosts may be fed upon at different periods in its develop- 
 ment. Usually the young larvae attach themselves to ground 
 squirrels or smaller mammals and remain upon these from 
 three to five days, after which they drop to the ground. 
 After a resting period of from one to three weeks the skin 
 is moulted and an eight-legged form appears, which in turn 
 attaches itself to some host and feeds for several days, 
 dropping to the ground and developing into the adult 
 
OIWFlR ACARINA 
 
 33 
 
 &r%< 
 
 Fig. 9 
 
 Fig. 10 
 
 Fig. 11 
 
 Fig. 12 
 
 Fig. 13 , Fig. 14 
 
 Figs. 9 to 14. — The spotted fever tick {Dermacentor venustus and Derma- 
 centor albipictus). (Hunter and Bishopp.) 
 Fig. 9, adult spotted fever tick which has deposited eggs. Fig. 10, larva 
 of spotted fever tick. Fig. 11, engorged nymph of spotted fever tick. 
 Fig. 12, the same, ventral view. Fig. 13, adult male of Dermacentor albi- 
 pictus. Fig. 14, adult female of Dermacentor albipictus, unengorged. 
 3 
 
34 
 
 CLASS ARACHNIDA 
 
 stage. In the adult stage still another host is sought, this 
 time usually some of the larger animals, such as domestic 
 cattle or sheep, and })robably in the wild condition such 
 
 Fig. lo.—Psoroptes communis, var. equi. (Reduced from Furstenberg, 
 after Murray.) 
 
 animals as the antelope or Rocky Mountain sheep or other 
 ruminants of the Rocky Mountain region. On these hosts 
 fertilization occurs and the females then drop to the ground 
 
ORDER ACARINA 35 
 
 where the eggs are laid and a new cycle begun. The disease 
 has some remarkable limitations in its distribution which 
 are probably associated with the distribution of the ticks or 
 the animals which serve as a reserve for the disease germs. 
 
 Family Sarcoptidse. — This family includes parasitic mites, 
 affecting particularly birds and mammals. 
 
 The Sheep Scab Mite {Psoroptes communis, var. oms). — 
 The sheep scab mite produces a very serious condition 
 among sheep, evidenced by matting and tagging of wool 
 and the formation of thick, encrusting scabs. The eggs of 
 this mite are minute, glistening white specks, longer than 
 broad and nearly uniform in thickness. They may be 
 found under the scabs by careful inspection, and their 
 detection, even when mites are not seen, may be taken as 
 evidence of the disease. 
 
 The larvse have nearly the same shape as the adults, but 
 are to be distinguished by the fact that only six legs are 
 apparent. 
 
 The full-grown mites are nearly as broad as long, and are 
 characterized by their piercing mouth parts and the struc- 
 ture of the two posterior pairs of legs (see Fig. 15). In the 
 male the fourth is much reduced, and the third bears a 
 long thread-like appendage passing the sucker, while in 
 the female this leg carries two long, thread-like organs and 
 no sucker. 
 
 The only treatment for this species worthy of recognition 
 is that of dipping, and this, if properly done, will secure the 
 extermination of the pest. A flock once freed will not 
 become again infested except by exposure to infected animals 
 or by the introduction of scabby individuals. 
 
 So important is this parasite deemed that many of the 
 States have adopted stringent laws for the quarantine of 
 infected animals and for prescribing dips that must be used. 
 
 The particular kind of dip is of less importance than the 
 thorough use of the one selected. The tobacco dips, sulphur 
 and lime dips, and also several of the patent dips prepared 
 by reputable firms can be recommended. The main objec- 
 tion to the latter, perhaps, is the fact that the user must 
 
36 
 
 CLASS A RA CIINI DA 
 
 pay a rather ex()r})itant ])ri(*e for a few simple ehemicals, 
 and further, in ease of the arsenieal dips, that lie ma\- not 
 know the ingredients or their proportions and thereby endan- 
 uer the animals treated. 
 
 The Itch Mite. — The iteh mite, or " iteh inseet," affecting 
 man is perhaps becoming a rather rare pest in civilized 
 communities, but since it occurs at times on domestic 
 animals, and in certain varieties becomes at times a serious 
 pest to sucli animals, it deserves mention here. Authors 
 
 Fig. 16. — Sarcoptes ficabiei: male and female. 
 Furstenberg, after Murray.) 
 
 (Reduced from 
 
 have differed greatly in their treatment of the species, some 
 making a different species for each host animal, believing 
 that they could find distinctive characters in the size, 
 arrangement of spines, etc.; but recent authors have com- 
 bined most of these under the one species, scabiei, though in 
 some cases retaining the varietal distinction for various 
 hosts. 
 All stages of the parasite occur on the host upon which 
 
ORDER ACARINA 37 
 
 it is absolutely dependent for existence. Generation after 
 generation may occur on the same animal. The mite 
 burrows under th^ skin, in this respect differing from scab 
 mites. 
 
 The adult mites are flattened, rather circular in outline, 
 and may be separated from related forms by the character 
 of the feet and by the presence of six short spines or thorns 
 on the thoracic portion and fourteen on the abdominal 
 portion of the body. 
 
 Eggs are deposited along the burrow as the mite extends 
 its channel into the deeper portions of the skin, and as they 
 hatch the young feed upon the surrounding tissues, and it 
 is said moult four times before maturity. When fully grown 
 they wander around and mate on the surface of the skin, 
 after which the females begin a fresh burrow. 
 
 Infection with this parasite is accompanied by intense 
 itching during the formation of pustules and inflamed areas, 
 and while in man it is usually confined to the base of the 
 fingers and between the knuckles, in aggravated cases the 
 whole hand and arm may become invaded. 
 
 The "seven-year itch," "army itch," and "Jackson itch" 
 are simply aggravated cases, where from lack of good sani- 
 tation the mites are able to thrive better than usual. 
 
 In the human subject the application of sulphur ointment, 
 in addition to frequent washing with soap and hot water, 
 and for domestic animals the use of washes and dips, as for 
 scab mites, are to be adopted. 
 
CHAPTER III. 
 THE SIX-FOOTED INSECTS. 
 
 The Ilexapoda, or the true insects, inchide those forms 
 with three pairs of legs, and the group is further distin- 
 guished from the other tracheate forms by large compound 
 eyes and for a considerable portion of the group the presence 
 of one or two pairs of wings. 
 
 Of the various arthropods this division includes by far 
 the greater number of species and to a large extent those 
 forms which have the greatest agricultural importance. 
 
 STRUCTURE OF INSECTS. 
 
 There are some details in the structure of insects that 
 have a special importance in connection with the use of 
 remedies and some that from their frequent use in the 
 description of injurious species require explanation as a 
 basis for proper understanding of these principles. These 
 will be treated here as briefly as may be, bearing in mind 
 constantly this main issue in their presentation. 
 
 The insect body is divided into three regions, head, thorax, 
 and abdomen. The first appears to be one solid segment, 
 though believed fundamentally to consist of six or seven 
 segments closely fused together. The thorax has three 
 segments usually pretty closely joined, while the abdomen 
 possesses from three to nine visible segments, and these 
 articulate so as to be free to move on each other. 
 
 The head bears appendages, a number of definite struc- 
 tures connected w^ith sensation or nutrition, and which are 
 of special service in separating the different groups of insects. 
 The antennse are jointed appendages usually situated on 
 the upper and front part of the head, composed of a varying 
 (38) 
 
STRUCTURE OF INSECTS 
 
 39 
 
 number of segments and modified in a great variety of ways 
 in different groups of insects. Some of these modifications 
 may be mentioned briefly. 
 
 The joints may be widened so as to appear toothed along 
 one margin, in which case they are called serrate. If con- 
 stricted at each end so as to appear like a string of beads 
 they are called moniliform; if expanded widely toward the 
 apex on one side they form a series of comb-like teeth and 
 are then said to be pectinate; if swollen toward the apex, 
 or club-shaped, they are called clavate; and if this swollen 
 portion is confined to a few of the terminal segments and 
 expanded so as to form a ball they are capitate. In moths 
 
 Spiracles 
 Abdomen 
 
 Prothorax Head 
 
 Fig. 17. — Anatomy of grasshopper. (Reduced from Packard.) 
 
 they may be provided with a series of plume-like expansions 
 on either side and are then bipectinate, or if extremel}^ wide 
 and feathery are called plumose. 
 
 The compound eyes are usually large and conspicuous, 
 and composed of an immense number of facets, these num- 
 bering in some insects many thousands, being especially 
 numerous in dragon flies, horse flies, and some butter- 
 flies. The ocelli are the more simple eyes, composed of a 
 single lens, and are often so minute as to be seen with diffi- 
 culty except by the aid of a lens. They may be three in 
 number, sometimes two and in some cases wanting. Usually 
 they are located between the compound eyes, and on either 
 
40 THE SIX-FOOTED IXSECTS 
 
 side a sliort distance from tlie marjj^iii of tlie comiK)!!!!!! eye, 
 and the tliird, if ])resent, lower down on the face and on the 
 middle line. 
 
 The lower ])orti()n of the face is divided into cJypeus, 
 which forms the basis for attachment of the lahrum or upper 
 lip, the movable flajvlike part which covers the front part 
 of the mouth. Beneath this are the strong mandibles 
 capable of cutting and tearing the leaves of plants, and in 
 some cases of inflicting a severe bite if handled. 
 
 Next to these is a pair of more slender appendages, the 
 auxiliary jaw^s or the ma.villcp. These have a jointed structure 
 and bear each a slender, jointed appendage called the 
 maxillary palpus. 
 
 Beneath the maxillse is the labium, which is in reality a 
 structure formed by the fusion of a pair of organs similar 
 to the maxillae and sometimes termed the second maxillse. 
 The first part of this organ is called the mentuin, and is 
 attached by the suhmeutum to the gula or basal part of the 
 head. Attached to the mentum are the glossa and 2^«^«- 
 glossce, at the sides of which are the labial palpi. 
 
 The structure of the mouth is of special interest on account 
 of the relation to the food habits. It becomes possible to 
 determine from this structure what the food habits of any 
 particular insect may be. Where the mandibles and maxillse 
 are w^ell developed and capable of biting and tearing the 
 foliage of plants, w-e may assume that the diet is herbivorous. 
 How^ever, if the insect captures and devours other insects 
 w^hile the mandibles appear wanting or they seem to have 
 developed a suctorial tube fitted for puncturing the tissue 
 of plants and animals, a liquid diet may be assumed, and it 
 will follow that insects of this kind would not be affected 
 by poisons applied to the surface of the plants. We have 
 here then a basis for the application of poisonous solutions 
 such as the arsenites, which are effective for those insects 
 w^hich consume the surface of the leaf, or, on the other hand, 
 for the application of oily substances for those of suctorial 
 habits which enables them to secure the juices of plants 
 without consuming any of the surface. For insects of this 
 
STRUCTURE OF INSECTS 41 
 
 latter type we must apply substances which penetrate the 
 body and close up the breathing pores, and for this, oily sub- 
 stances, particularly kerosene, tobacco extract, and various 
 other substances, are especially useful. The breathing pores, 
 as will be seen later, are minute openings along the sides of 
 the body, these being closed by minute quantities of an 
 oily substance, so it is easy to see how these substances 
 operate to kill the insect. 
 
 The central region of the body, the thorax, consists of three 
 distinct segments called the pro-, meso- and metathorax. 
 The first of these next to the head bears the front pair of 
 legs; the middle segment, or mesothorax, the second pair 
 of legs and the first pair of wings; and the hinder or meta- 
 thorax, the third pair of legs and the second pair of wings. 
 The legs are jointed appendages adapted for walking, run- 
 ning and jumping, sometimes for clinging, and consist of a 
 basal segment, the coxa; a large, strong segment, the femur; 
 a more slender segment, usually of the same length as the 
 femur, the tibia, and the terminal portion, composed of 
 from one to five small segments, called the tarsus. The 
 last segment of the tarsus usually bears a pair of strong 
 claws, and sometimes between these is located a disk-like 
 pad or brush called the pulvillus. 
 
 The wings, ordinarily four in number, are membranous 
 expansions of the body wall and are supported by stout, 
 thickened, and rod-like portions termed nerves or veins, and 
 the arrangement of these throughout the wings is spoken 
 of as neuration or venation. Wings are greatly modified in 
 different groups of insects. In some cases they are thin 
 and transparent in both pairs, as in the dragon fly. The 
 front pair may be thickened or leathery, as in the grass- 
 hoppers, or still more thickened, forming a hard, horny case 
 (elytra), as in beetles, or partially leathery and partly mem- 
 branous, as in Hemiptera. They are broad and covered 
 with minute scales in butterflies and moths (Lepidoptera) , 
 and the number is reduced to two in flies and mosquitoes, 
 the hinder pair being aborted or modified into special organs 
 called balancers or halteres. 
 
42 THE SIX-FOOTED INSECTS 
 
 The abdomen or third region of the body is composed of 
 about nine or ten visible segments that do not bear any 
 segmented appendages, but the terminal segments are 
 modified to form the external reproductive organs. The first 
 seven or eight segments have on either side small openings 
 into the, respiratory system, the spiracles, and there are also 
 usually two spiracles located on the thorax. They are so 
 small as to be scarcely visible without magnification. They 
 are connected internally with the delicate respiratory tubes, 
 the trachea, which extend throughout the body, so that the 
 air is distributed to all of the tissues and the respiratory 
 process is consequently carried on in all parts of the body. 
 The minuteness of the pores, as has been already mentioned, 
 makes it possible for the insect to be suffocated by a very 
 small amount of oily material spread over the pores, closing 
 them. 
 
 Some further details of structure will be given in connec- 
 tion with the general characters for each order. 
 
 The internal structure of insects may seem at first sight 
 to be of little relation to economic problems, but if it is 
 recognized that their modes of feeding and the character 
 of food depends upon the digestive organs, and their mode 
 of respiration is very directly connected with certain impor- 
 tant modes of treatment, and that all of their special senses 
 associated with the attraction to certain kinds of plants, 
 the attraction or repulsion to light or to odors, and in fact 
 that the activities of the insect, as a whole, are dependent 
 upon the organization, it can be realized that these structures 
 have a very direct relation to their injuries and to methods 
 of control. 
 
 The digestive system of the insects is in general like that 
 of all arthropods, the mouth opening being connected with 
 a pharynx, the esophagus merging with the crop, commonly 
 the first part of the stomach (proventriculus), in which the 
 food is received and undergoes some digestive changes; 
 following this the true stomach around which are a number 
 of gastric ceca that secrete the gastric fluids. Following 
 the stomach is the intestine, divided into the ileum, colon. 
 
STRUCTURE OF INSECTS 43 
 
 and rectum, and connected with this is the Malpighian 
 tubules which are excretory in function. 
 
 The circulatory system is simple; it consists of a delicate 
 tube near the dorsal wall, and in this the blood current is 
 carried forward and blood circulated freely through the 
 various tissues. 
 
 The respiratory system of insects is very different from that 
 of the vertebrates and in fact is of a type that occurs only 
 in part of the arthropods. It consists of a great number of 
 minute tubes, tracheae, which are distributed throughout the 
 tissues, so that the air contained in the tubes may be 
 brought in contact with tissues in all parts of the body. 
 Externally these tracheae open through the spiracles which 
 have been noted as located on the thorax and abdomen. 
 The tracheae arising from the abdominal spiracles in most 
 insects unite each side with a longitudinal tube running 
 through the abdomen into the thorax, and from this lon- 
 gitudinal one numerous smaller tracheae are given out, and 
 these in turn divide into smallerv branches until they ter- 
 minate in minute parts called tracheoles, which are so deli- 
 cate that the air contained in the tubes is readily absorbed 
 into the surrounding tissues. The movements of respira- 
 tion are fairly rhythmetical in expansions and contractions 
 of the body, expecially of the abdomen, serving to force 
 the air in and out of the spiracles. Minute valves in the 
 spiracular openings permit air to enter and closely hold the 
 contained air, so that further contraction of the muscles 
 serves to force the new supply of air out into the minute 
 tracheoles. It is very evident from the structure of the 
 respiratory system that contact insecticides which serve 
 to close the spiracles or which may penetrate along the 
 trachea and be absorbed into the tissues must serve very 
 effectively for the destruction of the insect. It is for this 
 reason that contact poisons, and especially oily substances, 
 such as kerosene emulsion, are so efficient in the control of 
 suctorial insects. 
 
 The nervous system of the insect consists of a ladder-like 
 arrangement of ganglia and fibers along the ventral wall 
 
44 THE SIX-FOOTED INSECTS 
 
 of tlu' })()(ly, sej)arating at tJic anterior end, so as to pass 
 around tlie eso])hat:jus, after wJiich there is a large mass, 
 frecjuently termed the eerel^rum, as it oeeupies the upi)er 
 l)art of the head. This ganghonic mass contains three 
 pairs of gangha, while the subesophageal is composed of 
 three or four, and the primitive distribution of thorax and 
 abdomen is one j)air of ganglia to each segment. This con- 
 dition is modified, especially in the higher insects, so that 
 the ganglia may be fused, causing a single ganghon in the 
 thorax, and five, three, or one in the abdomen. 
 
 Tlie various ganglia of this system act with considerable 
 independence and even dismembered parts of an insect may 
 maintain their movements if the ganglia are not destroyed. 
 
 The special senses present many diverse features as com- 
 pared with higher animals, but insects give good evidence 
 of possessing sight, hearing, smell, taste, and touch, although 
 the exact range of these functions may differ considerably 
 from the same senses of vertebrates. 
 
 The reproduction in insects agrees for the most part with 
 that of other arthropods, and except for certain remarkable 
 deviations, such as are found on the aphids and bees, a 
 general statement will suffice. Insects have separate sexes, 
 and in a great majority of cases the males and females are 
 distinct and usually may easily be distinguished by external 
 characters. The reproductive organs are located in the 
 abdomen, the ovaries in the central anterior part, and are 
 composed of a number of ovarioles or tubular structures, 
 within which the ova are developed and from which they 
 pass into the oviducts. These oviducts combine near the 
 end of the abdomen into a common duct leading to the 
 external opening. Frequently connected with this common 
 duct is a sac-like structure, the spermatheca, which serves 
 for the retention of the spermatozoa. In the males the testes 
 are located about as the ovaries, and lead by rather slender, 
 more or less curved vasa deferentia to a common duct which 
 leads to the external opening at the posterior end of the 
 abdomen. The external organs are modified widely in 
 different groups of insects, and in many cases furnish most 
 
THE TRANSFORMATION OF INSECTS 45 
 
 important characters for classification. In general they 
 consist, for the female, of the ovipositor, and in the male, of 
 external claspers and a central intromittent organ. 
 
 Mating, in many insects, is accomplished during flight, 
 but this is by no means general. 
 
 The eggs are fertilized in the oviduct, in most cases doubt- 
 less in the common duct, or in the vicinity of the sperma- 
 theca, and the spermatozoa enter the egg by way of a minute 
 pore termed the micropyle, located usually at one end of the 
 egg. 
 
 THE TRANSFORMATION OF INSECTS. 
 
 Insects, like all other animals, begin their development 
 from an egg, not unlike any other forms. They pass through 
 a series of more or less distinct stages in development from 
 the egg to the mature or adult form. These stages are desig- 
 nated for the insects in general as egg, larva, pupa, and 
 imago. While dift'ering greatly in the definiteness of separa- 
 tion between the dift'erent stages, it is convenient to use 
 these terms in tracing the life history of any insect and in 
 describing the character of each of the stages somewhat 
 more in detail and considering the bearing in the connection 
 with economic treatment. 
 
 The egg is generally a comparatively small object, con- 
 taining a considerable portion of yolk material and provid- 
 ing for some degree of development before hatching. The 
 shapes differ greatly in the difterent forms, perhaps the 
 most common, and consequently the most fundamental, 
 being an elongate, oval shape. Spherical forms are by no 
 means scarce, and flattened spherical, elongated spherical, 
 or even linear or cylindrical forms are very common. The 
 greater difference may be noted in the character of the 
 surface of the eggshell, which may be minutely reticulated, 
 striated, punctured, beset with fine spines, and frequently 
 having a distinct lid through which the larvse are to 
 escape. They may be placed loosely in suitable locations, 
 attached simply by a glutinous secretion, forced into the 
 tissue by the ovipositor, etc. For aquatic species they may 
 
46 THE SIX-FOOTED INSECTS 
 
 be arranged in clusters on tlie surface, attached to objects 
 above the surface, to leaves overhanging the water, to stems 
 of aquatic plants, either above or below the water line, and 
 for some of the distinctly aquatic forms ])laced upon the 
 bodies of the insects themselves. The period of incubation 
 varies enormously, some hatching immediately upon deposi- 
 tion, or, in some cases, preceding deposition, in which 
 case the insect appears to be viviparous and for the other 
 extreme remaining in the egg stage for many months, many 
 species passing the winter in this stage. Ordinarily the 
 eggs of any particular egg mass, or of any species, hatch 
 with great uniformity, so that larvse will appear at the 
 same time. This results at times in the very sudden appear- 
 ance of larvae in startling numbers and to the uninitiated 
 suggests the occurrence of some very remarkable invasion. 
 Usually no nutritive material, other than contents of the 
 egg, can be used during this period, but some species in 
 which the eggs are forced into plant tissues and in which 
 the egg covering must be very delicate, there is an absorp- 
 tion of fluids indicated by the distinct increase of the size 
 of the egg prior to hatching The hatching of the egg is 
 usually accomplished simply by pushing off of the egg-cap 
 or rupture of the egg membrane, but in some species it 
 depends upon external factors associated with the future 
 history of the larva. For instance, the eggs of the horse 
 bot fly are hatched only upon the application of friction 
 or moisture and warmth, conditions w^hich are brought 
 about when the horse licks the hair bearing the eggs and 
 thus provides ready means of transfer from the eggshell 
 to its mouth, thus providing the necessary conditions for 
 future development of the insect. The particular method 
 of hatching may therefore have very important relation 
 to preventive or remedial measures. 
 
 The larval stage is the active feeding stage during which 
 the growth of the insect occurs, and during this period there 
 are a varying number of moults, most frequently from four 
 to five, at which there is a rapid increase in size, the larva 
 accommodating itself to the tough, chitinous body wall, 
 which as soon as hardened is incapable of any expansion. 
 
THE LENGTH OF THE LARVAL PERIOD 47 
 
 The larvse present the most diverse characteristics for the 
 different groups of insects, and vary extremely even for 
 closely related species. There has been a distinct adapta- 
 tion to conditions during this stage, and larvae with slightly 
 varying habits have doubtless been affected by natural 
 selection in the same manner as adults have been affected 
 by their particular environment. 
 
 THE LENGTH OF THE LARVAL PERIOD. 
 
 The length of the larval period is also in a wide degree 
 an adaptation of this kind, which is frequently of the utmost 
 importance in economic treatment of the species. 
 
 The pupa stage is the connecting stage between the larva 
 and the adult, and may be similar to larval form or differ 
 markedly from it, according as the insect has incomplete 
 or complete metamorphosis. While in some forms it may 
 feed to some extent, the more common condition is that of a 
 quiescent non-feeding period. During this stage, however, 
 important internal changes occur which lead to the maturing 
 of the insect. For those forms which have a perfectly 
 quiescent pupa stage, various forms of cells are made within 
 which the pupation occurs, others secrete themselves in 
 rubbish, folds of leaves, crevices or cracks in bark, while 
 some construct a tough, silken cocoon as a permanent 
 protecting case. 
 
 The adult stage or imago differs usually from the preced- 
 ing stage in the acquisition of well-developed wings, except- 
 ing, of course, in the wingless forms, and especially in the 
 maturity of the organs of reproduction. The period of 
 life varies in the adult also in quite a degree for species 
 living over winter and others for varying periods, although 
 more commonly the adult perishes soon after the comple- 
 tion of the reproductory process. To indicate the various 
 forms of adults would be to review all the different groups 
 of insects, and hence need not be attempted even in brief. 
 
 A very distinct grouping of insects may be made with 
 reference to the definiteness of transformation. Those 
 which develop without marked changes between the different 
 
48 THE SIX-FOOTED INSECTS 
 
 stages are said to have incomplete metamor])li()sis (hetero- 
 metabolie). Those which have very striking or marked 
 (Hfferences between these stages, inchicHng the (Hstinctly 
 (juiescent, non-feeding ])n])a stage, are said to have comj)lete 
 metamorphosis (hoh)metahoHc). A third group is sometimes 
 noted for the primitive forms in which no change whatever 
 occurs, and in which no wings have developed, they being 
 said to be without metamorphosis (ametabolic). 
 
 A reference to some of the common injurious species, 
 in which the different stages are shown, will illustrate these 
 different phases of development. 
 
 CLASSIFICATION OF INSECTS. 
 
 At this point it is well to discuss in a brief way what is 
 termed the classification of insects. When we speak of 
 the different members of the animal kingdom or describe 
 some particular insect it is quite important that we have 
 and use a name which would be distinctive for that one 
 form. The general practice is to use two names for each 
 insect, namely, the genus name and the species name. 
 A species includes those w^hich are similar in habits and 
 characteristics and that may interbreed as a species or a 
 kind. A genus includes a number of species and a group of 
 genera with more general similarities form a family, and 
 families are grouped into orders. The order then is the 
 more general group and the class insecta includes about 
 twenty orders. 
 
 Apterygota (Primitive Wingless Insects). 
 
 Order 1. Thi/sanura, Bristle tails; Campodea, Lepisma. 
 Order 2. CoUemboIa, Spring tails; Podura, Smynthurus. 
 
 Pterygota (Winged Insects). 
 With Incomplete Metamorphosis. 
 
 Order 3. Orthoptera; Cockroach, locust, cricket, mole 
 cricket, "walking stick," "walking leaf." Biting mouth 
 
CLASSIFICATION OF INSECTS 49 
 
 parts. Anterior wings usually shorter and firmer than those 
 behind, or modified into wing covers. Both pairs are some- 
 times absent. 
 
 Order 4. Dermaptera; Earwigs. Biting mouth parts. 
 Anterior wings small; hind wings large, but folded both 
 longitudinally and crosswise. Posterior forceps. 
 
 Order 5. Plecoptera; Perla. Biting mouth parts. Two 
 pairs of wings or none. Larvae aquatic. 
 
 Order 6. Ephemerida; May flies. Adult mouth parts 
 degenerate and rarely used. Fore wings large, hind wings 
 small or absent. Larvae aquatic, with biting mouth parts. 
 
 Order 7. Odonata; Dragon flies. Biting mouth parts. 
 Two pairs of large unfolded wings. Larvae aquatic. 
 
 Order 8. Isoptera; Termites. Biting mouth parts. 
 Wings often wanting. Social in habit. 
 
 Order 9. Corrodentia; Book lice. Psocids. Biting mouth 
 parts, wings often wanting. 
 
 Order 10. Mallophaga; Bird lice. Parasitic, wingless, 
 with biting mouth parts. 
 
 Order IL Thysanoptera; Thrips. Suctorial mouth parts. 
 Wings very narrow, often rudimentary or absent. Only 
 three or four pairs of stigmata. Concentrated nervous 
 system. 
 
 Order 12. Hemiptera; Phylloxera, aphides, scale insects, 
 cicadas, bugs, water scorpions, lice. (Male scale insects 
 (coccidae) have complete metamorphosis.) Mouth parts 
 adapted for sucking and piercing. Two pairs of wings or 
 none. No compound eyes in parasitic forms which are 
 degenerate in several respects. 
 
 With Complete Metamorphosis. 
 
 (Holometabola.) 
 
 Biting Mouth Parts (Mandibulate) . 
 
 Order 13. Neuroptera; Ant lions, lace-winged flies. Two 
 pairs of glassy wings with many nervures. Larvae sometimes 
 aquatic. 
 
50 THE SIX-FOOTED INSECTS 
 
 Order 14. Mccojjfcra; Scorpion flies. Two j)airs of narrow, 
 membranous wings or none. Larva^ caterpillar-like. 
 
 Order 15. Trichoptera; Caddis flies. Hind wings usually 
 larger than fore wings, both folded like fans. The body is 
 hairy, rarely scaly. The larvae are somewhat caterpillar- 
 like, usually live in the water in special cases, and are 
 apneustic. 
 
 Order 16. Coleoptera; Beetles. Fore wings modified into 
 wing covers, hind wings folded when not in use. Larvae 
 ver}^ diverse, generally with feet. The little bee parasites 
 Strepsiptera are probably allied. 
 
 Suctorial Mouth Parts (Haustellate) . 
 
 Order 17. Diptera; Two-winged flies. Mosquito, midge, 
 gnat, gad fly, house fly. Sucking mouth parts, but some- 
 times with power of biting. Two anterior transparent, 
 unfolded wings and posterior "balancers" or "halteres." 
 Larva usually a footless maggot, without a distinct head. 
 
 Order 18. Siphonaptera or Aphaniptera; Fleas. Wingless. 
 Xo compound eyes. Ectoparasitic. Larva a footless 
 maggot. 
 
 Order 19. Lepidoptera; Butterflies, moths. Two pairs 
 of uniform, scaly wungs. Larva, caterpillar. 
 
 Mouth Parts Developed for Biting and Sucking. 
 
 Order 20. Hymenoptera; Ants, bees, wasps, gall flies, 
 saw flies, etc. Usually with four transparent wings. Larvae 
 are footless grubs, except in saw flies. 
 
CHAPTER IV. 
 LOWER PTERYGOTA. 
 
 (Wingless Insects — Bristle Tails and Sirring Tails.) 
 
 This group of insects includes those forms which are 
 primitively wingless, there being no trace of wing structure, 
 
 
 
 
 / 
 
 ■\ 
 
 
 
 /[ 
 
 
 
 ..■■ 
 
 
 
 ■■■■ M 
 
 
 
 
 
 h ■ 
 
 
 
 fe 
 
 1 
 
 
 
 '"' 4^^ 
 
 i '"'- 
 
 
 
 -^P^ 
 
 ^-\ ' 
 
 ' 
 
 ^^ii 
 
 -...^^^^, 
 
 — ^ 
 
 . 
 
 --' 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 - 
 
 Fig. 18. — Lepisma domestica: Adult female — enlarged. (After 
 Marlatt, Div. Ent., U. S. Dept. Ag.) 
 
 (51) 
 
52 
 
 LOWER PTERYGOTA 
 
 and the evidence showing conclusively that unlike certain 
 wingless forms, which are related to winged species, these 
 have not had any winged ancestry. These species are 
 minute, scaly, mouth parts fitted for biting. The develop- 
 ment is direct, the young hatching in the form of the adults 
 and developing by simple growth to the adult stage. 
 
 Fig. 19. — Lepisma saccharina: Adult — enlarged. (After Marlatt, 
 Div. Ent., U. S. Dept. Ag.) 
 
 Order THYSANURA. 
 
 This group, the "bristle tails," includes the forms which 
 are provided wdth three bristles or bristle-like appendages 
 at the posterior end of the body. The antennae are long. 
 
ORDER THYSANURA 
 
 53 
 
 slender, bristle-like, the body usually densely covered with 
 overlapping scales. 
 
 m 
 
 Fig. 20. — Lepidocyrtus piirpureus (Lubbock): 1, dorsal view of insect; 
 2, spring; 3, side view of dens showing serrations and barbed hairs; 4, 
 foot; 5, side view of mucro; 6, larval form; 7, eyespot of larval form 
 (From Ohio Naturalist. After Mrs. Alma D. Jackson.) 
 
 The common bristle tail of dwellings, Lepisma domestica, 
 is about one-half inch long, of a light silvery color, with 
 some darker bands on the back. They run with great 
 rapidity and are very smooth and flexible, so that they are 
 
54 LOWER PTERYGOTA 
 
 caught with difficulty. If cauglit the scaly covcriu^^ brushes 
 off readily as a hue, whitish dust. 
 
 A related species, Lep'hsnia saccharitia, is found, especially 
 in i)antries, bakeries, or in places where they can secure 
 starchy materials for food. In some cases they attack the 
 bindings of books or the starchy covering of labels, and may 
 cause a good deal of annoyance and injury in libraries. 
 
 Order COLLEMBOLA. 
 
 This order, including the spring tails, is characterized 
 at once by the strong spring which is folded under the 
 abdomen and which catches into a loop on the thorax. The 
 release of the spring from this throws the insect into the 
 air with a sudden spring, which doubtless serves it as a 
 protection against certain kinds of enemies. The species 
 are generally found in moist places in cellars, under loose 
 boards, chips, or stones, and some of them are found floating 
 on the surface of water in quiet pools or along the margins 
 of streams or ponds. They feed mainly on decaying organic 
 matter and are of little economic concern, but a few^ species 
 are credited with feeding on vegetation, especially in green- 
 houses. 
 
 THE LOWER WINGED INSECTS (PTERYGOTA). 
 
 The remaining groups are primarily winged, and a number 
 of the lower orders may be grouped together in this chapter. 
 
 Order ORTHOPTERA. 
 
 This order, including cockroaches, crickets, grasshoppers, 
 etc., is distinguished by the biting mouth parts being rather 
 simple and primitive in structure, the wings of rather simple 
 pattern, the front wings narrow^ and the hind wings broad 
 and folded in a fan-like manner, so as to be covered by the 
 fore wings when at rest. 
 
 They differ in their mode of locomotion, some having 
 rapid running movement, using all of the legs equally well, 
 others walking slowly, and others, more specialized, having 
 
ORDER ORTHOPTERA 
 
 55 
 
 the hind legs much enlarged and adapted for leaping. The 
 group is conveniently divided on the basis of their move- 
 ments into the running or walking and the jumping divisions. 
 Cockroaches. — Of these groups the cockroaches, family 
 Blattid(F, may be considered as about the most primitive 
 representatives for the winged insects, the Ephemerid^, 
 often placed as the lowest order, having been specialized 
 in the direction of aquatic life. This position is supported 
 by the primitive structure of the mouth, by the venation of 
 the wings, and also by the fact that they are to be found in 
 strata of the early Paleozoic era, the earliest to appear of the 
 winged insects whose structure agrees quite closely with 
 that of present-day cockroaches. No other winged insects 
 
 Fig. 21,- — Ischnoptera pennsylvanica. After Lugger. 
 
 have been found in any numbers in as early geologic forma- 
 tions. Cockroaches of the present t!me seem to be persistent 
 forms that have preserved ancestral characters. Their 
 life history is interesting on this account. 
 
 One species of cockroach {Ischnoptera pennsyhanica) is 
 fairly common in woods under bark of dead timber and 
 sometimes in houses. The females are often found with the 
 egg-capsules protruding from the body. It is abundant 
 all over the United States and is really an outdoor native 
 species. They have well-developed wings, and often fly 
 into houses and are found in stumps, under logs, etc., during 
 daytime, and make migrations during the night, or in the 
 
56 
 
 LOWER PrERYCOTA 
 
 evening and early niorin'ng. They are seldom aetive during 
 the bright part of the day. The egg-eapsules are bean-shaped 
 and contain 50 to 60 or more eggs packed closely together, 
 and after being carried some time are i)r()bably slowly 
 extruded, finally left in some crevice. Tlie young hatch 
 from the egg-capsules and for a time are somewhat gregarious 
 and are inclined to cluster together in company with the 
 adult. This may be simply an incident of location, though 
 
 Fig. 22. — The oriental roach (Periplaneta orienfalis): a, female; h, 
 male; c, side view of female; d, half-grown specimen — all natural size. 
 (From Marlatt, Div. Ent., U. S. Dept. Ag.) 
 
 it appears like maternal care. The young are similar to the 
 adults in shape, much flattened, and much lighter in color, 
 and the wing pads are scarcely visible. They grow by 
 successive moults, and with each moult the wdng pads 
 increase in size, until in the final moult they acquire the full- 
 sized wings of adults. The development of the nymphs 
 goes on somewhat irregularly during the summer months. 
 An introduced species, the Oriental cockroach {Pcrvplaneta 
 
ORDER ORTHOPTERA 57 
 
 orientalis), is a common species in houses and is responsible 
 for much annoyance in kitchens and pantries. Another 
 introduced species, the German cockroach {Ectohia ger- 
 manica), is much smaller, but a persistent pest in houses 
 and common in eating houses, bakeries, and other places 
 where starchy food is available. 
 
 The second family in the group, Mantidce, Praying Man- 
 tides, have the front legs much modified for capturing insects. 
 These legs have a peculiar structure. Instead of having 
 short coxse with elongated tibia, the coxae are very much 
 elongated. This is evidently correlated with the grasping 
 
 
 Fig. 23. — Praying mantis. (After Lugger.) 
 
 habit, and is paralleled in Emesidse and Nepidse. They are 
 rather tropical in distribution, occurring in the Southern 
 States. 
 
 One species, Phasmomantis Carolina, is found to some 
 extent in southern Ohio and north to Washington, D. C, 
 but is rarely taken in the northern part of the United States, 
 or, in general, north of 40 degrees of latitude. The pairing 
 habits of the adults are rather interesting. The females 
 often capture and devour the males during the process of 
 courtship. The eggs are laid in large masses attached to a 
 twig or some part of a plant, grouped together, lying one 
 
58 
 
 LOWER PTERYGOTA 
 
 over the other in a dense mass and exposed freely and rather 
 commonly attacked by ])arasites. 
 
 Fig. 24. — Diapheromera femorata. (After Lugger.) 
 
 Family Phasmidae. — The Walking-stick (Diapheromera 
 femorata). — The walking-stick is a common representative of 
 this family throughout this part of the country. It has a 
 
ORDER ORTHOPTERA 59 
 
 slender body and reduction of wings. The female is green 
 and the body is thicker than that of the male. In autumn 
 the bodies of the males become brown and resemble in color 
 the twigs on which they are found. This species has one 
 generation each year, hatching about the first of June, 
 and the adults maturing in the latter part of the summer. 
 The adults are found as early as the first of September. 
 They are most commonly found in trees and shrubbery, 
 at some little distance from the ground. Eggs are simply 
 dropped from the trees or shrubs on which the adults are 
 resting, and instances are cited where they are so abundant 
 that the dropping of their eggs makes a sound like the 
 falling of rain. The eggs rest on the ground and are pro- 
 tected more or less completely by leaves. They retain 
 their vitality through winter and early spring and hatch 
 in early summer. This represents a rather simple life-cycle 
 with an annual generation and one in which the winter is 
 passed in the egg stage. When these insects are so abundant 
 as to be injurious, it would be of service to rake up and 
 burn leaves, but they are not usually abundant enough to 
 do any great damage. Another way would be to spray the 
 trees with arsenical poison at the time the young are feeding. 
 They are leaf-feeding forms and would secure the poison 
 with their food. A grass-feeding species. Monomer a blatch- 
 ley, occurs in the Mississippi Valley. 
 
 Some of the tropical forms are more striking than this 
 native variety and show more forms of mimicry. One form 
 has wings in form and venation like the leaves of certain 
 plants, so that the insect is remarkably well protected. 
 Other forms simulate growths of lichens, etc. The whole 
 family seems built on the plan of representing protective 
 resemblances. Several species have the same form as the 
 walking-stick, but possess short wings. There is a wide 
 divergence in wing development. 
 
 The Locusts {Acrididcp). — The locusts include some of the 
 most important economic species. They are great pests in 
 some parts of the country. The group includes the old-world 
 migratory locusts, which still appear as an occasional plague 
 
60 LOWER PTERYGOTA 
 
 over some parts of northern Africa. The old-world species 
 is represented in this country most nearly by tlie western 
 migratory locust or the grasshopper of the western plains, 
 Melanoplus spretus. This western species, the devastating 
 locust, is far less destructive in the aggregate than one or 
 two other species, but has attracted more attention because 
 of complete devastation which follows its appearance. 
 There is one species in Argentina that has attracted a great 
 deal of attention and has been a great menace to the crops 
 of that country. 
 
 The Devastating Locust. — The devastating or Rocky 
 INIountain locust, is limited in its normal distribution to the 
 plateau region of the Rockies, the normal conditions for its 
 survival being the high altitude, dry atmosphere, and a 
 supply of grassy vegetation. They are most dependent on 
 the bufi'alo grass or other native grasses. The species became 
 important during the days of early settlement of that portion 
 of country just east of the mountains, because at times, 
 when vegetation ran short in its native breeding ground, it 
 migrated sometimes 300, 400 or 500 miles, reaching places 
 that were settled and proving extremely destructive to 
 growing crops. During the late 70's they were such a serious 
 source of injury that a very decisive effort was made to 
 work out their habits, life history, and means of suppression. 
 It is now generally assumed that it is only under conditions 
 when it becomes extremely abundant and must migrate that 
 it causes serious devastation outside of its regular breeding 
 ground. 
 
 The adults may fly long distances and after finding suit- 
 ble places for depositing eggs, bore into the ground with 
 the ovipositor and abdomen for one and a half or two inches. 
 The process consists of merely pressing the earth away by 
 the ovipositor, and denotes a great degree of power because 
 the eggs are preferably deposited in hard ground where 
 the soil is packed. The eggs are coated with a glutinous 
 secretion which protects them from the weather and they 
 remain in these little burrows through autumn and winter 
 and hatch early in spring. Sometimes they hatch before 
 
ORDER ORTHOPTERA 
 
 61 
 
 there is much vegetation and sometimes the young are killed 
 off in large numbers by late frosts. The young develop 
 pretty rapidly and are able to travel quite considerable 
 distances, especially if vegetation is scarce. They acquire 
 
 Fig. 25. — Melanoplus femur-ruhrum, female. (After Lugger.) 
 
 wings often as early as the latter part of June. Flights may 
 occur as early as July and often in August and September. 
 Migration probably occurs rather sparingly unless food 
 supply is scanty. 
 
62 LOWER PTERYGOTA 
 
 We lia\e se\'eral species in the eastern United States closely 
 related to the Rock\' Mountain species. The most common 
 
 Fig. 20. — Mclanoplus atlanis, male. (After Lugger.) 
 
 Fig. 27. — Melanoplus atlanis, female. (After Lugger.) 
 
 is the red-legged grasshopper {Melanoplus femur-mhrum) . 
 It is similar to the Rocky ]\Iountain species, but is not cap- 
 
ORDER ORTHOPTERA 
 
 63 
 
 able of any sustained flight. There is seldom anything like 
 a general migration. They will travel out of dry pastures 
 into corn, wheat and oat fields, and sometimes injure apple 
 trees. Their ordinary habitat is in pasture or meadow and 
 grass is their most common food. This species is abundant 
 all over the eastern United States; is an economic factor 
 
 Fig. 28. — The yellow- winged locust (Camuula pellucida): a, adult male; 
 b, female; c, nymph — somewhat enlarged. (After Simpson, Div. Ent., U. 
 S. Dept. Ag.) 
 
 year after year, and undoubtedly causes more damage than 
 the Rocky Mountain species. They do not usually destroy 
 the grass completely, but take a large share of the crop. 
 If they were eliminated the same acreage would supply 
 more hay, or support more cattle or other stock in pasture. 
 Plowing the ground where eggs have been deposited, rota- 
 
64 
 
 LOWER PTERYGOTA 
 
 tion of crops, and the catching of the newly hatched hoppers 
 in early summer before the damage has been done are 
 measures that will assist in keeping them in check. They 
 are preyed upon by several parasitic and predaceous insects 
 
 Fig. 29. — Trimerotropis maritima, female. (After Lugger.) 
 
 and by spiders and birds as well as fungous diseases, which 
 together serve to hold their numbers down. 
 
 iVnother very similar species, but with longer wings, and 
 which occasionally has a migration, but probably not so 
 
ORDER ORTHOPTERA 65 
 
 uniformly destructive, is Melanoylus atlanis. The wings 
 are long and the capacity for flight more like Melanophs 
 spreius, but flight seldom reaches more than a few miles. 
 
 The Beach Locust {Trimerotropis maritima). — The beach 
 locust is an interesting species that occurs along the coast 
 of the ocean as well as fresh-water lakes or where sand dunes 
 are common. The coloration and markings are very dis- 
 tinctly adapted for protection and the nymphs are really 
 about as well protected as the adults. They are conspicuous 
 on the wing, part of the wing being bright yellow in color, 
 but when they alight on the sand they immediately disap- 
 pear on account of the color and markings. They must 
 feed on grasses in such locations and are often found around 
 clumps of Juncus and Arenaria, but rarely seen feeding. 
 
 Fig. 30. — Trimerotropis maritima, male. (After Lugger.) 
 
 This species is found in June and July in the larval and 
 nymphal stages, and in different sizes, some comparatively 
 small, representing the second and third moult. Their 
 moults occur fairly rapidly during this particular time. 
 There is some difference in the time of hatching from eggs, 
 and adults are to be found by the early part of July. The 
 time varies in different seasons. Later in summer there will 
 be very few larvse and a large number of adults, and still 
 later only adults. The adults remain active and travel 
 over the sand for several weeks. They make characteristic 
 tracks on the sand, easily detected. They probably do not 
 5 
 
66 
 
 LOWER PTERYGOTA 
 
 mate until somewliat late in the season, seldom during mid- 
 summer, but probably by the latter part of August. 
 
 In regard to the deposition of eggs, it would seem that 
 they must select rather solid parts of the sand, but egg 
 masses have not been found. There is no way for the 
 nymphs to travel any great distance. The eggs must be 
 deposited during the autumn months, probably in September 
 and October. They survive the winter protected in the 
 
 Fig. 31. — Dissosteira Carolina, female. (After Lugger.) 
 
 sand or in places where there is more solidity in the soil. 
 The eggs hatch in the spring, probably in June, some perhaps 
 in May. It does not seem necessary for them to adjust 
 themselves particularly at this stage to any conditions, for 
 the life-cycle can be carried through easily in summer. 
 There is one generation a year. 
 
 The more common form is a rather light gray, with the 
 spots of a rusty color, and some spots of darker color, a granite 
 combination, resembling the surface of the sand. Another 
 
ORDER ORTHOPTERA 
 
 67 
 
 fairly common form has a brownish band or stripe on the 
 upper part of the thorax or wing covers, and making a promi- 
 nent Hne when the wings are closed. It occurs about as 
 commonly on the sand, but may have a preference for places 
 where there are little sticks. A less common form is lighter 
 colored, almost ochre yellow, and more common among 
 grass, leaves, and clumps. The color is close enough to the 
 general color of the sand to afford some protection on the 
 bare sand. 
 
 Fig. 32. — Arphia sulphurea. (After Lugger.) 
 
 Family Locustidse. — The family Locustidse includes insects 
 which are usually green in color and called green grasshoppers 
 or meadow grasshoppers, katydids, and stone crickets. 
 They are characterized by great length of antennse, the width 
 of wings, and generally a green color. They are common 
 among the coarse grasses along the roadsides and in 
 meadows. A rather striking group includes the sword- 
 bearers, Conocephahis, the striking feature being the form of 
 the head, which is extended in a prominent horn, varying 
 somewhat in size and shape in different species and with 
 long, slender antennae. The wing covers are somewhat 
 
68 LOWER PTERYGOTA 
 
 sword-shaped and the ovipositors also have a sword-Hke 
 shape. They are found during the latter part of the summer 
 as adults, occurring on grasses and low vegetation, but 
 seldom on shrubby plants or trees. The females use the 
 long, sword-shaped ovipositor for thrusting eggs into the 
 tissues of plants, and thus they are protected during the 
 winter time. The eggs hatch in the spring and larval devel- 
 opment occurs during the early summer, the adults appearing 
 in the middle or latter part of summer. 
 
 Katydids. — ^The katydids include several species, but 
 the one most properly called katydid has broad, concave 
 wings with rather prominent veins, quite strongly concave. 
 
 Fig. 33. — Conocephalus ensiger, female — natural size. (After Lugger.) 
 
 The name of the species is Cyrtophyllum concavum. They are 
 noted for their song, and sing particularly during the twilight 
 and early part of the night. This species is the best singer 
 of the katydids. Their life history is practically the same 
 as that of Conocephalus. 
 
 A species nearly related to this is the angular-winged 
 katydid, which deposits eggs on the surface of twigs, the 
 eggs overlapping each other like tiles on a roof. 
 
 Stone Crickets. — In this family also have been placed the 
 stone crickets. Most of them are included in the genus 
 CeuthojMlus. Quite a large number of species is included 
 in this genus. They have changed from the food habit of 
 
ORDER ORTHOPTERA 69 
 
 the other members of the group, and instead of feeding upon 
 ordinary vegetation they secrete themselves in dark places 
 and feed upon debris or decaying organic matter occurring 
 in such places. The character of the ovipositor is like that 
 of the crickets, but the head, antennae, and other parts 
 look like those of field locusts. The details of their life his- 
 tory are not fully worked out, but it is probable that there 
 is one generation a year. 
 
 Family Gryllidse. — This family includes the crickets and 
 may be separated into herbivorous, carnivorous, and omniv- 
 orous forms. 
 
 Oecanthiis, tree crickets. Oecanthus iiiveus, snowy tree 
 cricket, is most commonly referred to, but 0. fasciatus and 
 other species are more common. The larvae feed upon plant 
 lice and are distinctively carnivorous, and therefore are 
 serviceable during that stage. The adults may feed on flies, 
 but were formerly thought to be herbivorous. The adults 
 are found in autumn, and then they gather on various kinds 
 of trees, fruit trees, etc. Th-e eggs are forced into the twigs, 
 forming a series of punctures. The eggs are deposited in 
 two rows. They are elongated in form, and the masses of 
 eggs include forty or fifty eggs deposited by each individual. 
 The eggs remain in the twigs during the winter and are well 
 protected in that way. They are sometimes deposited in 
 galls on willows; if not by this species by one closely related. 
 Some eggs are forced into the stems of annual plants, Helian- 
 thus, Solidago, etc. The eggs hatch during the spring sea- 
 son and the larvse depend upon plant lice for food supply. 
 They grow to reach adult stage, when they probably feed 
 upon other insects. They are probably not destructive, and 
 the attacks upon plant lice make them valuable. They are 
 rather desirable on fruit trees, only in some cases the punc- 
 tures of the twigs result in rather severe pruning. 
 
 A quite common species on Helianthus is Oecanthus fas- 
 ciatus. There are four or five species that look a great deal 
 like the common forms. In the males the wings are broader 
 and very transparent. One form lays eggs in separate punc- 
 tures at different points. 
 
70 
 
 LOWER PTERYGOTA 
 
 The mole crickets are extremely specialized as subter- 
 ranean forms. They burrow in the earth and have become 
 adapted to this habit. They have a dense velvety covering, 
 which is doubtless serviceable as a protection against mois- 
 ture, etc. In one species the wings are considerably reduced, 
 but in another species they are longer. In all the species 
 the legs are well developed, and are excellent for digging and 
 burrowing, with toothed arrangements for pushing into the 
 soil, much as in the mole and other digging animals. These 
 teeth are mostly on the tibia. The tarsi are rather slender. 
 Almost the same kind of structures occur in certain beetles 
 
 Fig. 34. — Gryllotalpa Columbia: a, side view of anterior claw; b, the 
 same of G. borealis. (After Lugger.) 
 
 and in burrowing Hemiptera. The mole crickets feed on 
 vegetation, especially tuberous roots of plants; sometimes 
 they dig into potatoes. Ordinarily they are not abundant 
 enough to attract much attention. The long-winged form 
 flies at night and sometimes flies into houses. They are 
 completely covered with a fine pile, as velvety as that of a 
 mole, and are also as well fitted for burrowing. 
 
 EUPLEXOPTERA (DERMAPTERA). 
 
 Earwigs. — ^The earwigs, or Euplexoptera, are characterized 
 by the presence of four wings, the first pair of which are very 
 
EUPLEXOPTERA 
 
 71 
 
 short, veinless, and meeting in a straight hne when at rest, 
 the second pair of which fold both lengthwise and crosswise; 
 biting mouth parts; forceps-like caudal appendages; incom- 
 plete metamorphosis. 
 
 Fig. 35. — Labia minor. (After Lugger.) 
 
 These forms resemble rove beetles in appearance, being 
 very long and slender, but differ in having the caudal appen- 
 dages. They are found in the southern part of the United 
 States and on the Pacific Coast, and are very common in 
 parts of Europe, where they are troublesome, because of 
 their habit of feeding on flowers and fruits. 
 
72 LOWER PTERYGOTA 
 
 A common species in the northern states is Labia minor, 
 which occasionally may be seen flying in large numbers 
 around barnyards. It has not occasioned noticeable injury, 
 however, and is not counted of special economic importance. 
 
 Order PLECOPTERA. 
 
 This group includes the stone flies, and the species are 
 all aquatic, but in general characters they are pretty closely 
 related to the Orthoptera. The mouth parts are mandibu- 
 late, the front wrings are narrower than the hind wings, which 
 fold together and are covered by the front wings when at 
 rest. The transformations are incomplete, the larvse dis- 
 tinctly aquatic and provided with tracheal gills along the 
 side of the body, which permit them to absorb oxygen from 
 the water. The species have an importance as a source of 
 food supply for aquatic animals, and in some localities they 
 probably furnish a considerable support for certain kinds of 
 fishes. 
 
 The adults are usually found in the vicinity of water, on 
 tree trunks or rocks, but except as they may attract atten- 
 tion they have no particular importance. Unlike the May 
 flies, they are not strongly attracted to light, and are seldom 
 noticed except in their native habitat. 
 
 Order EPHEMERIDA. 
 
 May flies form an order frequently placed as the lowest 
 of the winged insects. While showing some simple structure, 
 we may consider their simplicity due to reduction or speciali- 
 zation. The mouth parts of adults are reduced, fore wings 
 large, hind wings small. They are specialized in the aquatic 
 habit of the larval stage. The genera and species are not 
 particularly numerous. The name Ephemera was applied 
 on account of their very short apparent life. They are 
 developed from aquatic forms that have a period of develop- 
 ment of from one to three years, but have a very short life 
 in the adult stage. There are many species that come out 
 
ORDER EPHEMERIDA 73 
 
 toward evening and fly for an hour or two, deposit their 
 eggs, .and then disappear. Other species Uve for several 
 days, some perhaps for a week or two. Their first flight 
 is in what is called the pseudimago stage. When coming 
 to rest they attach themselves to some convenient object, 
 and there the skin of this stage splits and the insect escapes, 
 leaving the skin still clinging to the object. After this 
 moult they are mature adults with full-sized wings, but with 
 a difference in texture, and in genital organs, which are not 
 fully developed in the pseudimago stage. For many of the 
 species it is probably safe to say that they mate the same 
 day that they come out of the pseudimago stage. The 
 normal method of mating is on the wing. Eggs are probably 
 deposited within a day or two, being laid either on the 
 surface of the water or else underneath the surface. This is 
 done by the adult folding the wings and descending beneath 
 the surface. In one species the eggs are extruded in long 
 packets and then the insect descends close to the water and 
 deposits them on the surface. 
 
 The eggs after deposition in one way or another — in or 
 on the water — hatch in a short time and the larvse grow and 
 probably migrate more or less in the water. They do not 
 have to come to the top of the water for respiration, as they 
 are fitted with organs which provide for aquatic respiration, 
 and probably live two or three years in the water. The 
 adults appear every year, and if the larvae require two or 
 three years to grow, there must be different broods, and if 
 there are two or three different generations in the lake, there 
 must be an enormous shifting of its population. They con- 
 stitute an enormous body of animal life, furnishing the basis 
 of food supply for other forms of animal life, fishes, etc., 
 which in a few days shifts its position and disappears, thereby 
 lessening the food supply materially. The larvae of these 
 nymphs come to the surface and the skin splits and the 
 pseudimago form issues and flies. The exuvise or skins which 
 are left on the surface drift in on shore and pile up in wind- 
 rows on the beach. 
 
74 LOWER PTERYGOTA 
 
 Order ODONATA. 
 
 This group includes the dragon flies and damsel flies, 
 insects with incomplete metamorphosis, biting mouth parts, 
 and large, net-veined wings without folds. 
 
 The larvae of these dragon flies and damsel flies are aquatic 
 and distinctly predaceous, feeding on aquatic animals. 
 The adults are also predaceous and catch insects in flight 
 very readily. The former, particularly, have very swift, 
 rapid flight, and may be seen darting here and there, espe- 
 cially in the vicinity of water, while the latter fly somewhat 
 more slowly. Both groups catch insects and feed upon 
 them, and so they are thought of as being beneficial, since 
 many of the insects that they feed upon are destructive. 
 
 The eggs in all cases are laid close to the water's edge, 
 either at or jusc above the surface, or in some cases attached 
 to stems of water plants beneath the surface. When the 
 larvae hatch they are already under water and can begin 
 their active life, preying upon the aquatic animals. In 
 both adult and larval stages the mouth parts are provided 
 with strong mandibles fitted especially for biting. In the 
 larval or nymphal stage there is a very peculiar enlargement 
 and elongation of the labium, so that it becomes a large 
 mask for the front part of the head, covering the outer 
 mouth parts and lower part of the face. These are provided 
 with a pair of very strong, clasping, or pincer-like organs, 
 which are used in capturing the aquatic animals on which 
 they prey. The elongated and jointed structure of the 
 labium permits the insects to thrust this forward a distance 
 of about half an inch from the head, so that they can reach 
 out and capture animals that, seem to be out of their reach. 
 These are snatched up very quickly and ground up with 
 their mandibles. 
 
 After passing the larval stage they crawl out of the water 
 on the bank of the stream or pond or sometimes on the stem 
 of a plant, then the nymphal case splits along the centre 
 line of the back, the adults draw themselves out of this 
 
ORDER DO NAT A 75 
 
 case, their wings expanding rather slowly or gradually. In 
 about a half-hour they are ready for flight. 
 
 Their very rapid movements and habits have given rise 
 to a number of common names. Aside from the dragon 
 fly they are called mosquito-hawks, which is quite appro- 
 priate on account of their feeding on mosquitoes. Sometimes 
 they are called snake feeders or snake doctors. In the 
 past the name devil's darning needle was quite popular, 
 although not used much at present. It was said that they 
 sewed up the ears of untruthful children. 
 
 Fig. 36. — Dragon fly Libellula pulchella. (Photo by author.) 
 
 These different common names illustrate different popular 
 interest in the group and forms of superstition. These 
 insects seemed to inspire a great deal of dread before their 
 life history and habits were known definitely. 
 
 The group Odonata can be looked upon as being very 
 useful and serviceable to mankind, as they feed on destruc- 
 tive insects, mainly mosquitoes and many aquatic organisms. 
 Of course they feed on useful insects as well as detrimental 
 ones, but it is generally believed that the majority are detri- 
 mental ones. 
 
76 
 
 LOWER PTERYGOTA 
 
 Throughout a large part of the country is found the 
 handsome LibeUuIa j)uchella, shown in Fig. 36. It is a 
 large species with pruinose body, and the wings are each 
 conspicuously marked with three black patches. This 
 species is seen very frequently flying over low meadows and 
 in the vicinity of ponds and rivers. Judging by the abun- 
 dance of the adults it must be one of the quite important 
 species as affecting the aquatic life, and the adults must 
 dispose of many troublesome pests. 
 
 Fig, 37, — Leucotermes flavipes: a, adult male; b, terminal abdominal 
 segments of same from below; c, same of female; d, male, side view, some- 
 what inflated by treatment with ammonia; e, abdomen of female, side 
 view; /, tarsus, showing joints and claw; a, d, e, enlarged; b, c, f, greatly 
 enlarged. (After Marlatt, Div. Ent., U. S. Dept. Ag,) 
 
 Order ISOPTERA. 
 
 This order is characterized particularly by the thickly 
 net-veined wings which fold flat upon the back and by the 
 biting mouth parts and incomplete metamorphosis. 
 
 The order includes one family, the Termitidse, in which 
 there is a remarkable separation of habits, the species living 
 in communities and showing much the same kind of adap- 
 
ORDER ISOPTERA 
 
 77 
 
 tation for community life as is shown in the ants. The 
 colonies usually include a large number of individuals, but 
 may vary from a few dozen to many thousands. Each 
 colony also includes several kinds of individuals, some of 
 
 
 a 
 
 Fig. 38. — Leucotermes flavipes: a, queen; 5, nymph of winged female; 
 c, worker; d, soldier. All enlarged. (From Marlatt, Div. Ent., U. S. 
 Dept. Ag.) 
 
 which are neuters, while others represent the males and 
 females of normal species. The males and females are 
 winged at time of maturity, but the wings are broken off 
 after flight, and thereafter these individuals, like the neuters, 
 
78 
 
 LOWER PTERYGOTA 
 
 ai)])car to be wingless, altlioiigli the stubs of the broken-oflf 
 wings may be noted. At tlie time of flight the different 
 individuals come to rest at different places, so that they 
 are pretty generally distributed. They then set to work 
 to form a new colony. This, however, is impossible unless 
 some of the workers are also located at the same place. 
 It often occurs that many die oflF, without establishing a 
 new colony, for lack of workers. 
 
 The colonies are located in the earth, or for some species 
 upon the trunks of trees, or in some of the tropical forms 
 
 Fig. 39. — Leucotermes flavijjes: a, newly hatched larva; b, same from 
 below; c, egg. All enlarged. (From Marlatt, Div. Ent., U. S. Dept. 
 
 Ag.) 
 
 large ant hills are built above ground which accommodate 
 immense numbers of individuals. 
 
 The white ants feed upon wooden fiber and make attacks 
 upon trees or upon dead timber and are especially destruc- 
 tive to wooden structures, so that in regions where they are 
 abundant they constitute a very serious menace to wooden 
 structures. They also feed very extensively upon wooden 
 furniture, books or papers in places accessible to them, and 
 the damage occasioned by such attacks is often very exten- 
 sive. 
 
ORDER ISOPTERA 
 
 79 
 
 The colonies include as neuters two forms: one, the 
 workers, having moderately large heads, strong jaws, and 
 adapted for carrying on the labor of the colon}', such as col- 
 
 FiG. 40. — Work of white ant (Leucotermes flavipes) in chestnut. 
 
 lecting food, caring for the young, and in fact, all of the 
 ordinary work of the colony. The other form, called soldiers, 
 has as its special function the protection of the colonies. 
 
80 
 
 LOWER PTERYGOTA 
 
 Tliey have enormous lieads, strong jaws, and are especially 
 fitted for attacking enemies that may enter the colony. 
 They are, of course, helpless against larger kinds of animals, 
 
 Fig. 41. — Termites and their work: a, adults working in the stem of 
 geranium (photograph by Wm. P. Beeching, Jr., Ohio Agric. Exp. Sta.) ; 
 6, enclosed gallery suspended from the underside of greenhouse bench 
 (photograph by J. L. King, Ohio Agric. Exp. Sta.). 
 
 but their bite is very severe and they doubtless in this way 
 serve as very effective guards against a numerous host of 
 smaller-sized animals. 
 
ORDER CORRODENTIA 81 
 
 The most abundant individuals are the workers and then 
 the soldiers. Both of these forms never acquire wings. 
 
 For this region and for the eastern and southern United 
 States there is one common species, Leucotermes flavipes 
 which is distributed as far north as the Great Lakes, to 
 Boston on the Atlantic coast, and into central Illinois in 
 the Mississippi Valley. The colonies of this species are 
 formed, usually under old logs or stumps, and from these 
 nests the termites construct tunnels, sometimes for long 
 distances, to reach dead wood, buildings or other structures 
 in which they can secure a food supply. Porches, fences, 
 and all sorts of wooden structures suffer from their attack, 
 but the greatest menace, perhaps, is to wooden trestles 
 and bridges which are likely to have sudden weight thrust 
 upon them. In feeding, the ants eat out the inner part of 
 the timbers, leaving an exterior shell, thus it happens the 
 timbers are greatly weakened before any indication is seen 
 upon the surface. 
 
 The most effective treatment is to locate the nest, give 
 it a thorough treatment of bisulphide of carbon to kill out 
 especially the reproductive individuals, so that the colony 
 will not be able to multiply. 
 
 Particularly the use of stone, brick or concrete foundations 
 in bridges or trestles and the separation of the wooden part 
 of structures from the earth in localities where white ants 
 are present will serve as a prevention from their attacks. 
 In tropical regions the practice is to use stone or metal, 
 not only for bridges, trestles, etc., but in many places for 
 railway ties, in order to avoid loss from the termite's attacks. 
 
 Order CORRODENTIA. 
 
 Family Psocidae. — Book Lice. — These are small insects, 
 a considerable number of them are entirely wingless, but 
 there are many species in which the wings are fully devel- 
 oped. The wings are held in a sloping position, a somewhat 
 roof-like arrangement over the abdomen, but not folded 
 flat, and have a rather small number of veins. Their appear- 
 6 
 
82 
 
 LOWER PTERYGOTA 
 
 ance is considerably like that of the plant lice, but they 
 have distinct biting mouth parts. They are totally different, 
 
 Fig. 42.— Clothilla. 
 
 Fig. 43. — Work of Atropos on grain. (Photo from Ohio Exp. Sta.) 
 
 though, in their method of reproduction. The more interest- 
 ing members of the group are those which are wingless 
 
ORDER MALLOPHAGA 83 
 
 and occur in houses, commonly found among books, old 
 papers, insect collections or herbaria, and which do a great 
 deal of damage in such places. 
 
 The common book louse, Atropos divinatoria, is most 
 abundant in houses among old books. They are too small 
 to be pinned, but they can be mounted on micro slides to 
 good advantage, for stud}^ with the microscope. They are 
 about one-sixteenth of an inch in length, rather flat, nearly 
 white, antennae slender, and eyes quite small. Their man- 
 dibles are strong and they feed on the mucilage and glue or 
 paste of book bindings, on the tissues of preserved insects, 
 
 B 
 
 Fig. 44. — Atropos divinatoria. 
 
 and they are quite detrimental to collections of plants in 
 herbaria. 
 
 They may be destroyed by fumigating with bisulphide 
 of carbon for half an hour or so. They are so very small 
 that it is almost an impossibility to exclude them entirely 
 from any place. 
 
 Order MALLOPHAGA (Bird Lice). 
 
 This order includes the biting lice infesting birds and 
 mammals. They are usually hard and horny and much 
 flattened. They possess mandibulate mouth parts adapted 
 
84 
 
 LOWER PTERYGOTA 
 
 to cutting and biting the hairs, feathers, epidermal scales, 
 or excretions on the bodies of their hosts. The mandibles 
 are situated in most forms underneath the head and near 
 the centre, the clypeus projecting and forming the most 
 anterior portion of the liead. TJie labrum is present and 
 the maxillary palpi are prominent in a part of the group. 
 The eyes when visible are located back of the antennae. 
 The antennte are five-jointed except in Trichodedes, where 
 they are three-jointed. The thorax is generally narrow and 
 
 ^'"% 
 
 Fig. 45. — The common hen louse (Menopon pallidum). Greatly 
 enlarged. (Banks, Div. Ent., U. S. Dept. Ag.) 
 
 frequently but two di\'isions are apparent. The legs are 
 adapted to clasping (Fhilopterida^) or to running (Liothe- 
 idse), the tarsi in the first case being short and in the latter 
 case being long, well adapted to running, and provided 
 with two claws. The members of the first division occur 
 on both mammals and birds, those of the second, except 
 Gyrojms, are limited to birds. Wings are entirely wanting, 
 and the abdomen contains nine or ten segments and is 
 usually oval in shape. 
 The eggs are glued to the hairs or feathers of the host 
 
ORDER MALLOPHAGA 
 
 85 
 
 animal and open with a circular cap or lid at the free end. 
 The larvae are less flattened, shorter in proportion, and 
 without the hardened parts common to the adults, covering 
 a part or all of the surface. The length of life and rapidity 
 of multiplication has not been determined accurately for 
 
 Fig. 46. — Trichodectes scalaris (biting cattle louse). (Bull. 5, Fig. 134.) 
 
 these insects and the habits of the insects make any such 
 determination a matter of considerable difficulty. 
 
 While it is, of course, very desirable that a more complete 
 knowledge of the life history of the species be secured, it 
 may be considered as already established that all the species, 
 with no known exception, pass their transformations on the 
 body of the fowl, and that, unlike the mites, they may be 
 
86 LOWER PTERYGOTA 
 
 attacked witli the assurance that e^<j:s and newly hatched 
 young are not developing in some out-of-the-way corner. 
 
 Moreover, the observations made on the length of time 
 required for the hatching of the eggs indicate that they 
 require a number of days at least, so that in repetition of 
 treatments intended to kill individuals hatched since a 
 former treatment a period of ten days to two weeks may be 
 counted on as probably short enough. 
 
 Fig. 47. 
 
 -Trichodecies parumpilasus (biting horse louse). (Bull. 5, 
 Fig. 133.) 
 
 It should always be borne in mind that lice must grow^ 
 from eggs laid by the adult louse, and can never originate 
 from filth or other matter. Chickens hatched in an incuba- 
 tor should be absolutely free from lice and remain so until 
 brought in contact with a lousy hen or put in a lousy chicken 
 house. 
 
 The effect of these lice may be less important than the 
 
ORDER THYSANOPTERA 87 
 
 suctorial lice, or the sucking ticks or mites; but judging 
 from the serious results following the efforts of the animals 
 to rid themselves, and from the known irritation due to 
 anything crawling among the hairs or feathers, it cannot be 
 doubted that they cause much annoyance and inconvenience 
 to the creatures that become their involuntary supporters. 
 The biting lice of cattle and horses are annoying pests 
 and demand the attention of the stockman. 
 
 Order THYSANOPTERA. 
 
 The species of this order are all very small and have 
 mouth parts intermediate between the biting mouth parts 
 of the Orthoptera and the suctorial mouth parts of the 
 Hemiptera. In some respects they may be considered as an 
 intermediate group between the Orthoptera and the Hemip- 
 tera, but not as a distinct connecting link between the two, 
 because in the matter of wings they have a specialization 
 of their own. They are minute, all very small, the largest 
 not over one-eighth to one-fourth of an inch in length. 
 Many are not over one-sixteenth of an inch long. They 
 have very slender bodies and slip around readily between 
 the parts of the blossoms of many different kinds of plants. 
 The different stages may occur in the bloom, and they feed, 
 at least in large part, upon the soft tissues of the parts of 
 the blossoms, puncturing and corroding them so as to secure 
 the juicy contents. 
 
 The mouth parts are drawn out in style-like form. Their 
 structure is partially like that of Hemiptera, but the styles 
 are not produced beyond the length of the head. They are 
 not capable of cutting and biting as the mouth parts of the 
 grasshoppers, nor are they strictly suctorial organs. The 
 wings are characteristic. In one division the wings are 
 narrow, with few veins and provided with quite long marginal 
 setae which furnish a large part of the area of the wings. 
 The hind wings of this form also have setse but no veins. 
 Another division has wings very simple, without any vena- 
 tion, and provided with enormously long setse. They are 
 
88 LOWER PTERYCOTA 
 
 l'rin<;r-\vi !!<;'('( 1 forms, a clianictoristk" striR'ture. Anotlier 
 character almost equally distiiK'tivc is found in an aborted 
 tarsal joint modified into a bladder-like ex])ansion of tlie 
 tarsus. This joint is evidently a modifieation from the 
 orchnary form with claws. Bladder-foot is one term appHed 
 to this iijrou]) and riiyso])oda is the name fjjiven in some text- 
 books, based on tliis ])arti('ular structure. 
 
 Tlie life liistory of tJie grouj) in general is ratlier sim])le. 
 Tlie adults deposit eggs at different periods tlu'ougli tlie 
 summer, the generations })eing somewhat irregular, often 
 tliree or four in a summer. TJie eggs are ratlier large for 
 tlie size of the insect and somewhat ovoidal or oblong in 
 shape, almost transparent. They are deposited on the 
 foliage or bloom of ])lants, and hatch quite promptly. The 
 larvie develoj) gradually by successive moults, without 
 any striking metanior])hosis, until they reach the adult 
 stage when wings are developed. Ik'tween the larval and 
 adult stages is a stage of quiescence; parts, including the 
 antennae and legs, are almost immovable. This may be 
 looked upon as a develo])meiit along the line of the more 
 striking metamori)li()sis in other cases. The eggs are 
 deposited by nieans of an ovipositor that differs in the two 
 subgroups of the family. In one case there is a saw-like 
 ovipositor with blades that glide on each other and enable 
 them to i)ush eggs into soft tissues. In the other division 
 the ovipositor consists of the elongated tubular abdominal 
 segments. The latter is a more sim])le condition, but the 
 former is more primitive. The latter probably results from 
 reduction, the saw-like structure being lost. The difl'erence 
 in egg dejKisition amounts sim])ly to position in which 
 eggs are laid: in the first instance they are laid more or less 
 within the tissue, in the second instance on the surface. 
 
 For the first grouj), Terebrantia, the common Thripidse 
 occur in clover, Comi)osita\ apple blossoms, milkweed, etc., 
 also in wheat blossoms. The food plant is determined simply 
 by the flowering season. The most abundant is the wheat 
 thri])s, Thri])s tritici; this is an economic sj)ecies, causing 
 some damage. 
 
ORDER THYSANOPTERA 
 
 89 
 
 In the spring they are found in apple bloom and a large 
 proportion of the blossoms are infested, as high as 80 per 
 cent, in one instance having been observed to be so damaged 
 as to render blossoms infertile. They also occur commonly 
 
 Fig. 48 Fig. 49 
 
 Fig. 48. — The pear thrips (Euthrips pyri) : ovipositor and end of abdo- 
 men from side. Much enlarged. (After Moulton, Bur. Ent., U. S. Dept. Ag.) 
 Fig. 49. — The pear thrips (Euthrips pyri): larva. Much enlarged. 
 (After Moulton, Bur. Ent., U. H. Dept. Ag.) 
 
 in strawberry bloom, and the injury to the bloom appears 
 to result in the distortion of the berry known as "buttoning." 
 When exposed they can be killed by spraying with kerosene 
 emulsion. 
 
90 
 
 LOWER PTERYGOTA 
 
 Pear Thrips [Eiiihrips pi/ri). — 'riie ])('ar tlirips has l)een 
 a serious ])est in California, attac*kiii»i; beside ])ear a niiml)er 
 of the relatcul fruits. Its attack is directed largely against 
 the bloom and tJie loss of fruit is serious. Contact sprays 
 are only partially effective, as the insect is protected so much 
 of tlie time within the ])arts of the bloom. 
 
 Grass Thrips {Aplidndfhrijhs' sfrlat(i). — 'J'lie grass thrips is 
 an extremel\' abundant s])ecies in tJie northeastern United 
 
 Fig. 50. — The pear thrips {Euthrips pijri) : nymph or pupa. Much 
 enlarged. (After Moulton, Bur. Ent., U. S. Dept. Ag.) 
 
 States, and lias been reported as destructive to oats in 
 Canada. It attacks the upper part of the plant and its injury 
 shows, especially in the blasting of tlie lieads of grass and 
 oats. In grass this is called "silver top," a condition of 
 wliitening and withering of the upper stem and seed head 
 which is })rol)ably })ro(hiced by other insects as w^ell as thrips, 
 but wliicli is no (h)ubt in hirge measure to be credited to 
 these almost invisible little pests. 
 Another species is Thrips tahaci — known now as onion 
 
ORDER THYSANOPTERA 91 
 
 thrips. It occurs on quite a large variety of plants. It is 
 similar to Thrips tritici in size, but different in some micro- 
 scopic details. It is injurious to onions. Massachusetts, 
 Iowa, Colorado, Rhode Island, and Ohio have all reported 
 
 Fig. 51. — The pear thrips (Euthrips pyri) : adult. Much enlarged. 
 (After Moulton, Bur. Ent., U. S. Dept. Ag.) 
 
 extreme injury from this species. The degree of injury is 
 determined in large part by temperature, moisture, etc. 
 It occurs on many plants besides onions. In dry seasons 
 it becomes very injurious to the onions. The leaves wilt 
 and show whitening, and the injury is easily recognized. 
 
92 LOWER PTERYGOTA 
 
 The life liistory is a matter of adaptation to different 
 plants. There are pr()l)al)ly several jjjenerations in one 
 summer and hibernation in mature larval or adult stage. 
 
 Mullein Thrips {Phloeothrips verhasci). — The mullein thrips 
 has a definite restricted food plant and the herbivorous 
 character of the insect can be easily established. It is a little 
 black species found in mullein plants the year through. 
 In early spring they are found among the bases of the mullein 
 leaves. They seldom try to fly, but creep about among the 
 fine hairs of the mullein leaf. They are very common in the 
 mullein plants and there are very few plants without them, 
 so examples may almost certainly be found wherever mullein 
 occurs. The eggs are laid soon after the leaves are well 
 started in the spring and there is a pretty definite brood. 
 
 The adults of this brood mature about the time the blos- 
 soms appear, this being the softest portion of the plant 
 at this period. Later on adults in resting period are found 
 in seed pods or secreted around the base of the plants. 
 There are two generations in the summer ; the adult individ- 
 uals appearing first in the spring, then again in the sum- 
 mer, and again in the autumn. They do not do any great 
 damage to the leaves, although they feed upon this plant 
 exclusively. 
 
 Another species, Phloeothrips nigra, occurs in clover 
 bloom. It is a black species and evidently restricted to 
 clover. The larva is bright red and often found during 
 the winter. They feed on part of the clover bloom and so 
 far as it has any effect, is destructive to the clover. One 
 , species is credited with feeding upon the grape Phylloxera. 
 If it does this it is an exception to the usual food habit of 
 the family. It possibly may feed ordinarily upon the tissue 
 of the gall and exceptionally on the plant lice that occur 
 within the gall. 
 
 The group as a whole is to be considered as herbivorous 
 rather than carnivorous, and injurious when occurring on 
 useful plants. 
 
CHAPTER V. 
 ORDER HEMIPTERA. 
 
 The Hemiptera constitutes one of the large orders of 
 insects and includes some of the very important economic 
 species, and some of the very striking specializations in 
 insect life history including extremes in different kinds of 
 environment, life habit, and one of the most striking extremes 
 in the matter of reproduction and development. 
 
 The essential character of the order is found in the devel- 
 opment of the mouth parts, there being also other distinct 
 differences in the matter of wing structure and some other 
 parts of the body. The mouth parts are adapted for suction 
 in the larval as well as the adult stages. This represents a 
 more radical change of these parts than when the mouth 
 parts are different in different stages. The modification 
 in the mouth parts consists in the change of the mandibles 
 and maxillae into bristles or setae which serve to puncture 
 the tissues of the plants upon which the insects feed by 
 pumping out the juices. The labrum (epipharynx of some 
 authors) is present as a rather aborted structure ; the labium 
 is modified into a sheath for the bristles or setse and is usually 
 three- or four-jointed. These segments are fitted together 
 to form a sheath or tubular or furrowed organ within which 
 the bristles or setse play back and forth as they are driven 
 into the tissues which constitute the food of the insects. 
 Within the group there are differences in wing structure 
 which enable us to separate the group into two very distinct 
 suborders, and in some cases three are recognized, the third 
 including only parasitic forms. 
 
 The two main suborders are the Homoptera and the 
 Heteroptera, the first including those forms which have 
 
 (93) 
 
94 
 
 ORDER IIEMIPTERA 
 
 membranous or opaque, but homogeneous wings; the seeond 
 having the front wings thiekened at the base and membranous 
 at the apical portion. The Heteroptera are often given first 
 as if more primitive, but the Homoptera appear to have the 
 most fujidamentally primitive character. The venation 
 of the wings and the position of the head particularly seem 
 of more primitive character than in the Heteroptera. 
 
 The third group, Parasita, includes the suctorial lice; 
 the wings are lost, beak is single-jointed, and setse are very 
 much elongated and tubular. They are restricted to the 
 w^arm-blooded vertebrates, mammals. 
 
 Fig. 52. — The periodical cicada {Tihiceyi septendecetn) : a, adult; b, 
 same, side view; c, shed pupal skin. Natural size. (After Mailatt, Bur. 
 Ent., U. S. Dept. Ag.) 
 
 The Homoptera are divided into two divisions, Auch- 
 enorhynchi and Sternorhynchi. In the first group the beak 
 is free, not attached to the sternum, and may be moved 
 readily from the head as its base. In the second group it 
 is fused into the sternum and the base connected with the 
 head at about right angles to the sternum. This latter is 
 a specialized condition and must be derived from the simpler 
 condition where the beak is free. 
 
 In the Auchenorhynchi the Cicadida? are one of the most 
 prominent families, which is apparently rather generalized 
 in its features. They show specialization in their life his- 
 
ORDER HEMIPTERA 
 
 95 
 
 tory. The most common species, or, for the Homoptera, one 
 of the most widely known, is the seventeen-year cicada, 
 which is especially remarkable on account of its long life. 
 The seventeen-year cycle is certainly known and well estab- 
 lished by observation. The adults appear at these periodical 
 intervals in the latter part of June and they are apparent 
 
 Fig. 53. — Tibicen septendecem: adults on two-year-old apple tree. 
 (Photo from Ohio Exp. Sta.) 
 
 during this stage when they feed very slightly on vegetation, 
 mate and deposit their eggs during a period of four or five 
 weeks, though they are seen in great abundance for a period 
 of only a few days. They are noticeable from their size 
 and from the very loud note that is produced by the males. 
 The song is a long-drawn-out sort of screech and is produced 
 
96 
 
 ORDER HEMIPTERA 
 
 by an organ located in the base of the abdomen, covered 
 by the wings when folded and slightly covered from below 
 by an operculum. The structure of the drum is somewhat 
 flattened and inside is a cluster of muscles attached to the 
 
 Fig. 54. — Tibicen scplcndtcem: adults 
 
 (Photo from Ohio Exp. Sta.) 
 
 apple tree. 
 
 abdominal wall. Their contraction serves to draw this 
 membrane in, after which it immediately resumes its former 
 position and when repeated rapidly this causes a vibration, 
 producing a whirring or buzzing note which varies in inten- 
 sity with the rapidity of the vibrations. Its purpose has 
 
ORDER HEMIPTERA 
 
 97 
 
 been interpreted as that of a mating call, but no auditory 
 organ has been described. The females deposit eggs in 
 twigs of trees, puncturing the trees with little furrows, which 
 result in splitting the bark, and the twigs often die. The 
 
 Fig. 55. — Tibicen septendecem: twigs broken from egg deposition. 
 (Photo from Ohio Exp. Sta.) 
 
 eggs hatch five or six weeks after their deposition. The 
 larvae drop from the twigs and pass into the ground and from 
 that time on for almost the next seventeen years are out of 
 sight and are growing gradually, moulting occasionally, 
 
 7 
 
98 ORDER IIKMJPTERA 
 
 l)r()l)iil)ly once ii year tit letist. TJiey feed for the most ])art 
 on tlie roots of trees and shrubs and woody plants occurring 
 in their location. WJien trees are cut away after the eggs 
 are depositcMl, some of the nympJis douhtless fail to develop, 
 hut there are some that become mature. 
 
 TJie uniformity' in tlieir appearance may be accounted 
 for by the fact that those that did not come out at a definite 
 time had little chance of breeding and re])r()ducing. They 
 occur throughout the eastern United States and the seven- 
 teen-year form mostly to the north of the latitude of the 
 Ohio river. To the south of that latitude there is a thirteen- 
 year form. They do not occur over the whole area of the 
 country in which they may be considered as native, there 
 being portions where they do not occur at all, other places 
 where they occur twice in seventeen years, and still other 
 places where tht^v occur three times in seventeen years. 
 They may be descendants of a generalized mass of cicadas 
 \vith a shorter life period. Just why they have been retarded 
 is another problem. Their subterranean habit and conse- 
 quent slow growth might serve to prolong their life. 
 
 The dog-day cicada w^hich appears commonly in August, 
 lays its eggs in twigs of various trees, but the growth of 
 the nymph is much more rapid. The injury is the same as 
 in the seventeen-year cicada. The attacks of the adults 
 in young orchards are sometimes serious. 
 
 After the Cicadichv the Membracidae are perhaps the 
 most generalized, though they present a specialized struct- 
 ure of the thorax. They are called treehoppers, the majority 
 inhabiting trees and shrubs, a few only occurring on her- 
 baceous i)lants. The specialization of the thorax is shown 
 in various ways. The prothorax is the greatest part of the 
 body visible from above. There are many variations and 
 these result in a great many forms of mimicry and protec- 
 tive resemblance. Some forms have the posterior ])art of 
 the prothorax broken up into globular pieces simulating the 
 body of an ant. In some cases there are three large knobs 
 which hang out from the central part and probably resemble 
 parts of the tree on which it occurs. They take on the 
 
ORDER HEMIPTERA 
 
 99 
 
 greatest variety of forms, many very grotesque. The group 
 is large and includes many species. There are probably 
 fifty species in the latitude of the Northern States. 
 
 One of the most common is the buffalo treehopper, 
 Ceresa hubalu.s, which abounds on thorn, apple and maple 
 trees and is frequently found on other vegetation. It is 
 of an apple-green color, with faint, light yellow mottlings 
 
 Fig. 56. — Buffalo treehopper: a, female; b, enlargement of foot; 
 c, antenna; d, wing; /, g, ovipositor; h, ?, terminal segment of male abdomen; 
 
 e, terminal segment male taurina. 
 Ag.) 
 
 (After Marlatt, Bur. Ent., U. S. Dept. 
 
 or specks, distributed over the pronotum. The pronotum 
 itself stands out in two prominent horns. It extends back 
 in a very pronounced spine. The eyes are quite prominent 
 and stand out at the sides of the head. There are four species 
 closely related, but this one is the most abundant. Its life 
 history is quite characteristic for the group. They are 
 single-brooded and the winter is passed in the egg stage; 
 the eggs are deposited in twigs of various trees in little slits 
 
lUU 
 
 ORDER HEMIPTERA 
 
 of the bark, with sHghtly crescent-shaped scars, and eggs 
 are arranged in parallel rows, causing damage to the trees. 
 The young hatch in the spring and early summer and as 
 hatched they are quite grotesque. The body is shaped 
 something like that of an adult, but along the dorsal line there 
 is a series of sharp spines, the divisions of the body are fairly 
 well marked and the divisions of the abdomen are distinct. 
 
 Fig. 57. — Ceresa bubalus. Twig of apple showing: a, female at work; 
 b, recent egg puncture; c, bark reversed with eggs in position, slightly 
 enlarged; d, single row of eggs still more enlarged; c, wounds of two or 
 three years' standing on older limbs. (After Marlatt.) 
 
 There is no such expansion of the prothorax as in the adult. 
 They moult several times and with the aquisition of the wdngs 
 the pronotum becomes fully expanded. The moults occur 
 mainly in June and July and the adults appear usually in 
 the latter part of July. Deposition of eggs occurs rather 
 early in the fall. A considerable part of the year is spent 
 in the egg stage. Injury is caused by pumping the sap and 
 
FAMILY FULGORIDjE 
 
 101 
 
 is limited to a rather short period, but the injury caused 
 by puncturing the twigs for egg deposition does not fully 
 appear for a year or two after the eggs are deposited. The 
 scars and distorted growth of the twig may seriously dis- 
 figure and weaken the branch. It is rather difficult to apply 
 any distinct remedy because they occur on so many different 
 kinds of plants. Cutting off the infected twigs would be 
 possible but hardly practicable on any large scale. The 
 
 h 
 
 Fig. 58 Fig. 59 
 
 Figs, 58 and 59. — Ormeriis pruinosa Say: at right, a and b, adults; at 
 
 left, a, eggs, much enlarged; b, eggs in bark; c, twig with eggs. (After 
 Lugger.) 
 
 application of kerosene emulsion would be effective at the 
 same time that other forms are developing, thus killing off 
 more than one species at one time. 
 
 Family Fulgoridse. — The family Fidgoridoe presents ex- 
 treme specialization in some directions. These occur in the 
 head region instead of the pro thoracic region. In one 
 of the most extreme forms the head is spread out into a 
 great peanut-like structure, and in one form there is an 
 
102 
 
 ORDER HEMIPTERA 
 
 appearance of a large spot on this head portion, and in one 
 species there is stated to be phosphorescence. Tlie tliorax, 
 wings and abdomen have for the most part normal character 
 or some variation in the wings. It is an enormous family, 
 especially represented in the tropics. There are few strik- 
 ing members of the group represented in northern latitudes. 
 A good many of the forms are inconspicuous. A few special 
 forms representative of the group may be mentioned. 
 
 Fig. 60. — Fulgorid. (Original, from drawing by Miss Edith Hyde.) 
 
 Otioceras. — Otioceras is as elegant a little insect as can 
 be found in any group of insects. They appear very much 
 like delicate little moths. The head is drawn out into a 
 ploW' share-shaped form. The eyes are prominent and the 
 antennae very peculiar, with little flabella-like appendages. 
 The eyes stand out at the sides of the head, the wings run 
 back in a moth-like form and are quite delicately veined 
 and marked. These occur mainly on hickories or closely 
 
FAMILY FULGORID^ 103 
 
 related trees, in August and September or October. They 
 may be obtained by beating the trees over an umbrella with 
 a stick. The genus includes six or eight common species. 
 They are quite similar in general appearance. 
 
 Delphacidae. — The Delphacidse are characterized by the 
 presence of a large, movable spur on the end of the tibia, 
 and tibia and tarsal joint run out with spines. A specialized 
 appendage for attachment to twigs, stems of grass, etc., 
 enables the insects to jump more readily. This is a charac- 
 teristic structure for this group. These hoppers occur 
 abundantly in low vegetation, especially on grasses and 
 some species are abundant enough to be detrimental, as for 
 instance, the corn Delphacid (Dicranotroins maidis), and the 
 sugar-cane hopper, which has been extremely destructive 
 in the sugar plantations of the Hawaiian Islands. Our 
 species occur sometimes in blue-grass meadows, and do some 
 damage. They are minute, varying in size from one and 
 a half to two millimeters, to four or five millimeters in length. 
 They present a great variety of modification in wing develop- 
 ment. Some are dimorphic. There are some in which the 
 hind pair of wings are wanting or not full-sized, some in 
 which front wings are reduced entirely or to mere rudiments. 
 This occurs first in the females, but also in some species in 
 the males. The greatest amount of reduction appears to 
 occur in those which live where food supply is abundant 
 and flight becomes unnecessary. There may be a summer 
 generation without wings and a fall generation with wings. 
 One other interesting feature is the fact that they are para- 
 sitized in a peculiar manner. Certain Hymenopterus para- 
 sites deposit eggs on the bodies of these and larvse are pro- 
 duced in a sort of sack extruded between the segments of 
 the abdomen, and within this sac the larvae develop. These 
 parasites may have some value in reducing the number of 
 the hoppers. 
 
 The eggs are deposited in the leaf or stem of grasses, etc., 
 and the larvae hatch from these and feed on the plant 
 attacked. The stages of development are gradual and there 
 are one or two broods annually for the most of the species. 
 
104 
 
 ORDER HEMIPTERA 
 
 Some of the forms have adult hibernation and others egg 
 hibernation. 
 
 Family Cercopidse. — The CercopidcB is a family that has 
 few economic species. They difi'er from the Fulgorida? in 
 having the head and thorax rather normal in shape, first 
 pair of wings usually thickened opaque and venation not 
 very consi)icuous. The thorax is well developed, the tibia 
 terminates in a prominent crown of spines and no spines 
 
 Fig. 61. — Aphrophora A-notata Say: a, from above; b, from side. 
 (From Lugger, Minn. Ann. Rept. 6.) 
 
 on the sides of the tibia. These include the little frog hop- 
 pers or "spittle insects." The larvse suck the juices of the 
 plants on which they occur and pump out more juice than 
 they have use for and extrude it from the body in fluid form 
 and set air free within this juice, making the frothy mass 
 which covers the entire body of the larvse. These masses 
 are found hanging on the stems of plants very frequently 
 during the summer. After they have passed through the 
 
SUPERFAMILY JASSOIDEA 105 
 
 larval and pupal stages they do not secrete any such frothy 
 masses. 
 
 Superfamily Jassoidea. — The superfamily Jassoidea in- 
 cludes several subdivisions of considerable importance. They 
 abound particularly on low vegetation, and some are grass 
 feeding, others tree inhabiting. They differ from the Ful- 
 goridse in the more specialized and compact head and 
 thoracic region and in the more distinctive character of the 
 hind tibia which is more prismatic in form and wdth two 
 rows of spines and without any circle of spines at the tip. 
 The subdivisions are separated by means of the venation 
 of the wings, and by the head parts. There are four fairly 
 distinct families. 
 
 The life histories are somewhat complex. Some species 
 have a single brood each year, others two, others apparently 
 three. Some hibernate as adults, many as eggs, some 
 apparently in partially developed nymphal stages. Some 
 of the striking examples are the grass leafhoppers, forms 
 that live continually in the grass and suck the sap, causing 
 a considerable decrease in the crop, reducing quantity and 
 quality of the nutritive contents of the grass leaves. In 
 some the individuals are extremely abundant, one to two 
 millions to the acre. 
 
 The life histories are much the same throughout the group, 
 but not many have been worked out in detail. The group 
 stands as one of the most specialized of the Homoptera 
 that have the primitive condition of the mouth parts. 
 
 The term vertex is used for the upper surface of the 
 head between the eyes and extending to the front border, 
 which may merge gradually into the front or the face. The 
 frons, or front, is the part of the face lying between the 
 sutures and extending down nearly to the lower border. 
 At the sides of this are portions next the eyes, which are 
 termed the cheek, and below the front a part called clypeus, 
 at the sides of which are the lorse. The central part of the 
 body which bears the wings and legs is termed the thorax, 
 and the upper portion of the first segment is known as the 
 pronotum. The front wings are termed elytra and are 
 
106 
 
 ORDER HEMIPTERA 
 
 usually thicker and stronger than the hind pair, which are 
 concealed beneath the front ones when at rest. The abdo- 
 
 FiG. 62. — Explanation of terms, from drawing of Athysanus obtutus: a, 
 female from beneath; b, from side; c, from above; d, female genitalia; 
 e, male genitalia; /, larva or nymph; g, eggs, showing developing larvae; 
 h, egg, enlarged; i, eggs in position beneath sheath of grass stem. Structural 
 details: ac, apical cells; a.ac, anteapical cells; cL, clavus; clyp., clypeus; cox., 
 coxa; fr., front; fern., femus; lora, lora; ov., ovipositor; plate, plate; pr., 
 prothorax; py. ((f), ry. (P), pygofer; tar., tarsus; lib., tibia; v., vertex; 
 vs., terminal ventral segment; valve, valve. All enlarged. (After Osborn 
 and Ball.) 
 
 men may be entirely hidden above by the wings, but in 
 short-winged forms is more or less exposed. The parts of 
 greatest importance on the abdomen for purposes of descrip- 
 
SUPERFAMILY JASSOIDEA 
 
 107 
 
 tion are the terminal segments, including the genitalia. In 
 the female the last ventral segment is frequently of a par- 
 ticular shape or structure for different species and in many 
 groups is of the greatest service for description. It is fol- 
 lowed by the sheaths of the ovipositor, this latter being a 
 narrow, saw-like pair of blades, extending to the tip, some- 
 times considerably beyond the tip of the sheaths. The 
 males have a terminal segment beneath a modified segment, 
 called the valve, which is followed by two movable pieces 
 called plates. Above these, forming the sides of the last 
 
 ^ . J (\ A« U \ .\ o\t a\» . 
 
 Fig, 63. — The clover leaf hopper (Agallia sanguinolenta) : a, adult; h, 
 nymph, side view; c, nymph, dorsal view; d, face; e, elytron; /, female 
 genitalia; g, male genitalia. All enlarged. (After Oshorn and Ball.) 
 
 segment, are the pygofers. A ready understanding of these 
 various parts will be helped by a study of the accompanying 
 figure, in which they are located and named. For the 
 different stages of insects the usual terms egg, larva, or 
 nymph, pupa, and adult are used, as these are sufficiently 
 definite in indicating the steps of development from the 
 egg to the mature form. 
 
 Bythoscopidse. — The Bythoscopidce include forms which 
 are for the most part found upon trees or woody plants, 
 sometimes in great abundance and which doubtless occasion 
 considerable injury, although the effect in any particular 
 
108 
 
 ORDER HEMIPTERA 
 
 case may not be very apparent. The common species 
 affect willows. 
 
 Idiocerus alternatus lays eggs in the bark and passes 
 through two generations each year. 
 
 Fig. 64. — Glassy- winged sharpshooter: a, adult?, seen from above; b, 
 side view; c, venation of forewing, enlarged; d, antennse; e, section of 
 hind tibia; /, 9 genitaha, more enlarged; g, serration of ovipositor, still 
 more enlarged. (From Howard, Bur. Ent., U. S. Dept. Ag.) 
 
 Clover Leafhopper. — Another form of considerable eco- 
 nomic importance, the clover leafhopper, is a very common 
 pest of clover and alfalfa and has been noted as troublesome 
 in sugar-beet fields. 
 
 Family Tettigoniellidse. — The family Tettigoniellidoe in- 
 cludes an enormous number of species occurring in the 
 tropics and a considerable number of common forms through- 
 
FAMILY TETTIGONIELLID^ 
 
 109 
 
 out the temperate regions, among them a particular species 
 known as the sharpshooter, Oncometopia undata, which 
 discharges droplets of liquid, so that when the insects are 
 abundant, the tree in which they occur may shed consider- 
 
 FiG. Q5.—Dr(BCulacephala mollipes: a, adult from above; b, face, much 
 enlarged; c, vertex and pronotum d"; d, female genitalia; e, male geni- 
 talia; /, wing; g, h, nymphs. All enlarged. (After Osborn, Bur. Ent., 
 Bull.' 108.) 
 
 able liquid, and this leads to the name "weeping tree." 
 The glassy-winged sharpshooter, figured here, has a similar 
 
 habit. 
 
 Tenderfoot Leafhopper.— A species which is very abundant 
 in grass lands is the tenderfoot leafhopper, Dmculaceyhala 
 
no 
 
 ORDER HEMIRTERA 
 
 molliyes. This is li^ht ^rass-^reeii in color, quite slender, 
 has a very sharply pointed liead, and is very well ])r()tected 
 on the blades of grass both by its color and form. It occurs 
 on a great variety of grass plants and is known all the way 
 
 Fig. 66. — The shovel-nosed leafhopper (Dorycephalus platyrhynchus: a, 
 female; b, male; c, face; d, female genitaUa; e, male genitalia; /, eggs in 
 grass stem; g, eggs; h, egg, more enlarged and showing developing nymph; 
 i, j, k, I, different stages of growth of nymph. All enlarged. (After 
 Osborn and Ball.) 
 
 from Canada to Central America. The nymphs have 
 fairly well-marked longitudinal stripes arranged as shown 
 in the figure, but are much less commonly observed than 
 the adults. 
 
FAMILY JASSIDM 
 
 111 
 
 Family Jassidse. — The family Jassidoe, including the forms 
 which have the ocelli located in the margin of the head be- 
 tween the vertex and front, is very largely represented in 
 temperate regions and many of the species affect important 
 cultivated crops. 
 
 Fig. 67. — The inimical leafhopper (Deltocephalus inimicus): a, adult; 
 b, face; c, vertex and pronotum; d, female genitalia; e, male genitalia; 
 /, elytra; g, nymph. All enlarged. (After Osborn and Ball.) 
 
 Shovel-nosed Leafhopper { Dorycephalus platyrhynchus) . — 
 The shovel-nosed leafhopper is a rather large species with 
 an enormous prolonged head and is found upon the wild 
 oat, Elymus canadensis. The eggs are laid beneath leaf 
 sheaths, a considerable number in a compact row and the 
 
112 
 
 ORDER HEMIPTERA 
 
 nymphs on hatching begin feeding at once upon the grass. 
 The adult females have short wings and do not jump or fly 
 rapidly. 
 
 Inimical Leafhopper { Deltocephalus inimicus). — The in- 
 imical leafhopper is perhaps the most abundant species 
 throughout the northern United States where blue grass 
 is a common pasture grass. While abundant and almost 
 
 Fig. 68. — The inimical leafhopper (Deltoccphalus inimicus) : nymphal 
 stages: a, newly hatched; h, c, d, later stages, the details of tarsal appen- 
 dages shown below. All enlarged. (After Osborn, Bur. Ent., Bull. 108.) 
 
 universal in blue grass, it may also be found upon other 
 species of grass and also in wheat and alfalfa. This species 
 is so abundant and wide-spread that it is almost impossible 
 to sweep a patch of blue grass in any locality from Maine 
 to Washington, and south to northern Tennessee, without 
 finding it in abundance. The nymphs pass through five 
 distinct stages with differences in the shape of the head and 
 development of wing pads and an increase in the number 
 
FAMILY JASSID^ 
 
 113 
 
 of minute appendages on the first tarsal segment, as shown 
 in the figure. 
 
 The destructive leafhopper {Athysanus exitiosus), was 
 first noticed as a pest in grain fields in the Southern States, 
 
 Fig. 69. — The destructive leafhopper (Athysanus exitiosus) : a, adult 
 female, dorsal view; b, head and pronotum of male; c, face of female; d, 
 female genitalia; e, male genitalia; /, wing; g, eggs dissected from female; 
 h, i, j, three stages of nymphal growth. All enlarged. (After Osborn, 
 Bur. Ent., Bull. 108.) 
 
 but is now known to be distributed throughout the larger 
 portion of the United States, which likely is the result of a 
 dispersal from the southern localities with possible intro- 
 8 
 
II I 
 
 OHhI'lh' IlI'lMII'TiaiA 
 
 (lil(li(Hi IVom (he WVsJ liidirs oi* Mexico in sonic iiol (jisljmt 
 |)ci"io<i. 
 
 Six-spotted Leafhopper. Tlic si\-s|)ollc(l icjil'lioppcr occiii-s 
 ill iil)iiii(laiicc t lii*oiif;lioii( (lie ('oiiiili-y .mikI is ;ilso w (-oiiiiiioii 
 species ill l^'nrope. Wliellicr i(s coimiioii distrihiitioii is due 
 to ori<;iii!il cxlciil of I lie species, (H- wliellicr tlic s|)ecies lias 
 been iiilrodiiccd iiilo America in niodeni iinies, is inip(>ssil)le 
 to say. Il dc\ clops rallicr rapidly and appaiciilly |)a.sses 
 tliron^li 1\V(> or lliree ;;'eiiera(ioiis at least in iKH-llicrn locali- 
 ties, and |)ossil)ly three to (i\(' in the more southern States. 
 It is es|)ecially iiiiinions in oat fields. 
 
 I''l<i. 70. Tlic .six-M|M.|lc(l l.>;iriii)|)i)ci- {('inidiilit {\iii>l<ilii): </. iidiiK ; 
 /*, fiic(«; (', \\\\\n.; <l. liMii.'ilc >!:»Mii(jili!i; r, mjiU^ ^(Miilnliii; /. iivmpli. All 
 tMiliii-k'cd. (Allvr OslH.rn. Hull. lOS, liiir. lOiit., U. S. Drpl. Ak.) 
 
 Typhlocyhida' inchides a <;'rou|) ol' mimite forms most of 
 which are found on trees or woody plants, hut certain ones 
 occur on i;fains or i;rasses. The most familiar and destruc- 
 ti\c forms are (he «;rou|) of leafho|)pers which cause witli(>r- 
 iiii;- and whitcnin;;- of n-r;,|)e-\in(>s in the midsummer and 
 autumn. Tuphlonilxi conir.s includes S(>\('ral xarictics, all 
 of which are d(»s(ruc(i\(' (o i;rai)es. lli(> nym|)hal s(a,i;'es 
 Ix'iii^^ found usually (Ui (he under side of ihc lca\(>s. and the 
 elVeet of their |)unc(urinj;- shows in miniilc while sjxyls on 
 the u])])er surface of the leaves. 
 
FAMILY I'SYLLID.K 
 
 iir, 
 
 Apple Leafhopper {Empnasca mall). T\\v ',\\)\)\(' l(';il"lj()i)i)('r, 
 juiolluM- very destructive form, jdVccts ;i|)i)I(' Jiiid other 
 IVuit trees. Oeeasioiuilly it is destriK live to ;dl'iill';i, cow 
 |)e;is, i)otMtoes Miid Ix'Miis. 
 
 Fio. 71.— Pesir-ireo p.syllii: .idiilt fctiiMlc iwitiinil Hi/>(! indif!il,(!(l l»y Hide 
 lino. (From Miuhilt, l)\v. Kui., 11 S. l)v])\. An,.) 
 
 Tlie Sfrrnorhi/nrlii include those I Ioinoj)ter}i thjit iuive 
 the beak fused jnto tlie st(;riunn. The ^n-oup contains some 
 reriKirkahly specialized forms of insects an(l there are four 
 distinct famihes, closely linked together by connecting 
 forms. 
 
 Psyllidae. The l*sj/lll(l(i; seem closely relate<l to tJic 
 cicadas. TJie shai)e of tlie body and licad is like that in the 
 
116 
 
 ORDER HEMIPTERA 
 
 cicadas, wings specialized, and they differ in the beak 
 being fused into the sternum. They are descended from a 
 generalized insect like the cicada in character. The prin- 
 cipal line of specialization has been in the fusion of the beak 
 and sternum. It stands out at almost right angles to the 
 prothorax, between the front legs. 
 
 All of the species are quite small. Some feed directly on 
 the surface of plants. Others present a distinctly specialized 
 food habit, producing galls on various trees, expecially 
 on the hackberry. 
 
 Fig. 72. — Pear-tree psylla: n, egg; h, larva, but greatly enlarged. 
 (From Marlatt, Div. Ent., U. S. Dept. Ag.) 
 
 A common and destructive species in the Eastern States 
 is the pear psylla which causes serious loss in pear orchards. 
 
 One of the most common is PachypsyUa celtidis-mamma. 
 The larvae are found in cavities in the galls; the galls are 
 formed by the deposition of eggs on the surface of the leaves 
 and the stimulation of the leaf celh. The life-cycle must 
 be adapted to the growth of the leaf on which it occurs. 
 In the gall, when dried up in the fall, are found either adults 
 or mature nymphs. The adults usually emerge and secrete 
 themselves in fallen leaves, etc. The adults appear in the 
 spring at about the time that the hackberry leaves are ex- 
 panding and deposit eggs on the surface of the leaves, and 
 
FAMILY APHIDIDM 
 
 117 
 
 during the rapid growing period of the leaf these galls are 
 developed and the larvae are growing within them. There 
 is a single generation during the year. This is the plan of 
 development for practically all of these psyllid galls. A 
 number of different kinds occur on hackberry trees. They 
 are readily identified by the character of the galls produced 
 on the trees. Most species are located on the leaves, but 
 some species form a structure on the twig by a modification 
 
 Fig. 73.- 
 
 -Pear-tree psylla: nymph greatly enlarged. 
 Ent., U. S. Dept. Ag.) 
 
 (From Marlatt, Div. 
 
 of the bud. There is a distinct specialization in the matter 
 of food supply which characterizes a large part of the family 
 Psyllidse. Stimulation of the plant tissues is produced by 
 the action of the larvae in puncturing the cells. 
 
 Family Aphididse. — This family is specialized particu- 
 larly with reference to the mode of reproduction. It agrees 
 with other forms of the Sternorhynchi in having the beak 
 apparently fused with the prosternum, so that the beak 
 appears to arise from the sternum. There is a reduction of 
 
118 ORDER HEMIPTERA 
 
 the venation in some genera. The forms witli the most 
 numerous \eins are the more primitive and tlie fewer-veined 
 forms must be regarded as speeialized. 
 
 The nectaries, or so-called "honey tubes" or "cornicles," 
 are structures peculiar to Aphididiie, located on the hinder 
 l^art of the abdomen. Fluids may exude from their tii)s and 
 much difference of ojiinion has existed as to their functions. 
 Some think that the fluids are used as a means of defense. 
 It is now generally accepted that the "honey dew" emitted 
 by plant lice is discharged from the anal opening, and con- 
 sists of slightly modified sap from the plant to which the 
 aphid is attached. It is sweet and may form some sugar on 
 evaporation and is much sought by ants and some other 
 insects. 
 
 Aphids are characterized by the appearance of several 
 successive generations which are devoid of wings and closely 
 confined to their host plant. Reproduction is in large 
 measure parthenogenetic, many generations occurring with- 
 out the appearance of the sexual forms. A rapid rate of 
 reproduction is provided for; sometimes as many as ten or 
 twelve generations in a season. It has been estimated that, 
 starting with one stem-mother in the spring, her progeny 
 during the season, if not curtailed, would amount to bil- 
 lions or trillions of individuals, sufficient to overrun the 
 world or to equal in bulk of organic matter the population 
 of China. The agamic eggs are termed "pseudova," and 
 are often developed and hatched before being extruded 
 (ovoviviparous). 
 
 No general statement can be made which will properly 
 cover the life history and development of all species, but in 
 general, and in the temperate latitudes particularly, hiber- 
 nation takes place in the egg stage. As the usual thing these 
 eggs are fertilized and occur on the plant which was the last 
 host of the species in the autumn. In the spring these eggs 
 hatch into stem-mothers, which are asexual individuals and 
 for which there is no corresponding male. They do not 
 require fertilization and they produce either eggs or living 
 young. The young produced are ordinarily wingless when 
 
FAMILY APHIDID^ 119 
 
 they mature and as many as two or three generations of 
 these agamic apterous forms may be produced. Next, 
 alate (winged) forms are produced, usually asexual, to pro- 
 vide for a migration of the species to another host plant. 
 As a general thing these winged migrants usually produce 
 mainly wingless, agamic forms. In the autumn a winged 
 form appears (usually asexual) which permits the return of 
 the species to its original host. Frequently with aphids 
 having alternate food plants the spring and autumn host 
 plants are perennials — woody or shrubby plants, the sum- 
 mer host plant an annual. A number of cases, however, of 
 alternation between woody plants are known. An example 
 of the former is seen in the case of an apple-plant louse, 
 Siphocoryne avenoB, which winters over in the egg stage 
 on apple trees, the spring forms occur for two or three 
 generations on apple and then apparently disappear; in 
 reality they migrate to wheat and breed on it during the 
 summer. With the ripening of the wheat the lice leave 
 and return to the apple. In the case of the hop-plant louse, 
 Phorodon huniuli, the spring and fall forms occur on wild 
 plum and the midsummer forms by migration on the hop 
 plants, which accounts for their very sudden appearance 
 and in such large numbers in the hop vineyards in summer. 
 
 The return migration in autumn to the original host 
 plant may be followed by two or three generations of 
 asexual, agamic individuals. After that, a short time prior 
 to the end of the breeding season, the sexual forms are 
 produced. The appearance of the sexual forms may possibly 
 be induced (or precipitated) by the ripening and hardening 
 of the plant tissue of the host. The same factor, in case of 
 the summer annual host plant, may determine the time of 
 the return migration to the spring and autumn host plant. 
 
 The sexual forms are often wingless and very small and 
 are less dependent upon the host plant for food than are 
 the other forms. Aher mating, the female produces one or 
 two eggs or at least a very small number of eggs and these 
 eggs are usually attached to permanent parts of the tree, 
 seldom to leaves or stems. These eggs are usually hard, 
 
120 ORDER IIEMIPTERA 
 
 tough, iisiiall>' black, polished and resistant to the weather. 
 They are sometimes so abundant on the surface of apple 
 twigs as to give the latter a shiny appearance. The follow- 
 ing spring these eggs hatch into the stem-mothers. 
 
 Control. — Control measures in general resolve themselves 
 into destruction of the over-wintering eggs, prompt appli- 
 cation of insecticides in early spring, and such measures as 
 are applicable through recognition of the alternate-host 
 habit. The hop-plant louse control depends on elimination 
 of the alternate host, wild plum. 
 
 To the general and usual method of hibernation in the 
 egg stage there are exceptions. Thus the corn-root louse 
 is carried over the winter on roots in the ground by its 
 attendant ant. Through this dependence on the ant being 
 long-continued this species has evidently become independent 
 of the egg-depositing habit or produces eggs only at intervals. 
 
 Outbreaks of plant lice are often very destructive and 
 and are more or less evanescent. The lice appear suddenly, 
 to all appearances, and often seem to disappear as quickly. 
 The aphids are victims to a multitude of predaceous enemies 
 and Hymenopterous parasites, are susceptible to weather 
 conditions, such as rains, low temperatures, etc. 
 
 Migrations in spring are usually for short distances, rarely 
 over a mile or so, or until a suitable summer host is found. 
 Fall migrations, involving many more individuals, are much 
 more general and the insects more widely scattered, and are 
 carried along by winds and may be quite widely distributed 
 at that time. Among the important species are the corn- 
 root louse, hop-plant louse, cherry aphis, apple aphis, etc. 
 
 An intimate relationship exists between the plant lice and 
 ants, this being sometimes carried so far as to make the 
 insects mutually dependent on each other. Such is the case 
 with the corn-root louse and its attendant ant, in which the 
 ant depends for its food upon the honey dew of the aphid 
 and the latter in turn depends upon the ant for its trans- 
 portation from one root to another. In this and other cases 
 plant lice are definitely protected by the ants or carried over 
 from season to season in order that the ants may get the 
 
FAMILY APHIDIDyE 
 
 121 
 
 benefit of the honey dew which is extruded from the anal 
 opening. There is no very definite glandular structure con- 
 nected with the nectar tubes or cornicles but a liquid does 
 come from them and its function is interpreted in various 
 ways, one being that it serves the insect in defence against 
 predaceous or parasitic enemies. 
 
 ==^ 
 
 Fig. 74. — Pea aphis {Macrosiphum pisi): a, winged female; b, same 
 from side, with wings folded in natural position, as when feeding; c, apterous 
 female; d, nymph in last stage; e, third joint of antenna of winged form; 
 a and d, much enlarged; e, more highly magnified. (From Chittenden, 
 Div. Ent., U. S. Dept. Ag.) 
 
 The classification of the Aphididse is based largely on the 
 structure of the winged forms, and it is very desirable that 
 the winged form of a species be obtained in attempting its 
 identification. 
 
 Other characters of special value are found in the antennae, 
 
122 
 
 ORDER HEMIPTERA 
 
 relative length and nnmber of joints, location of sensoria 
 in the honey tubes or nectaries, and the anal style. 
 
 FiCx. 75. — Spring grain aphis (Toxoptera graminum) : male, greatly 
 enlarged. (From Webster, Div. Ent., U. S. Dept. Ag.) 
 
 Pea Aphis. — The pea aphis is a species which occasionally 
 multiples to an enormous extent and causes heavy losses 
 
 Fig. 76. — Spring grain aphis (Toxoptera graminum): egg-laying female 
 with eggs in body, greatly enlarged. (From Webster, Div. Ent., U. S. 
 Dep. Ag.) 
 
 in the pea crop. Another very destructive species at times 
 is the one affecting melons. 
 
FAMILY APHIDID.^ 123 
 
 Spring Grain Aphis. — The spring grain aphis or ''green 
 bug" {Toxoptera graminum) has attracted a great deal of 
 attention, especially in the Southwestern wheat growing 
 sections; in Texas, Oklahoma, and Kansas where it has 
 caused severe injury to the wheat crop. It is an introduced 
 species and seems especially adapted to the Southern wheat 
 districts. It is extensively preyed upon by a small parasite 
 
 Fig. 77. — The spring grain aphis {Toxoptera graminiwi) : winged migrant, 
 much enlarged; above, antenna of same highly magnified. (After Pergande, 
 Div. Ent., U. S. Dept. Ag.) 
 
 (Lysiphehus) , and this parasite assists in a large degree in 
 keeping it in check. 
 
 Corn-leaf Aphis. — The corn-leaf aphis {Aphis maidis) is 
 injurious to the corn plant and occasionally appears in 
 destructive numbers but ordinarily is less injurious than the 
 related corn-root aphis. 
 
 Corn-root Aphis {Aphis maidi-radicis) . — The corn-root 
 aphis is a special pest of cornfields and a larger part of its 
 attack is confined to this crop. It is a light green or bluish- 
 
124 
 
 ORDER HEMIPTERA 
 
 green, affected evidently by its subterranean ha})it. The 
 species is notable on account of its dependence on the ant 
 for its transfer from one food plant to another. 
 
 Fig. 78. — The corn-leaf aphis (Aphis maidis) : winged female. Much 
 enlarged. (After Webster, Div. Ent., U. S. Dept. Ag.) 
 
 Fig. 79. — The corn-leaf aphis (Aphis maidis): wingless female. Much 
 enlarged. (After Webster, Div. Ent., U. S. Dept. Ag.) 
 
 The eggs of this species are cared for by the ant through 
 the winter time. When hatched the young are transferred 
 to suitable plant roots, often to the roots of weeds in the 
 
FAMILY APHIDIDJ^ 
 
 125 
 
 Fig. 80. — The corn-root aphis (Aphis maidi-radicis) : winged female. 
 Much enlarged. (Webster, Div. Ent., U. S. Dept. Ag.) 
 
 Fig. 81 Fig. 82 
 
 Fig. 81. — The corn-root aphis (Aphis maidi-radicis): wingless female. 
 Much enlarged. (Webster, Div. Ent., U. S. Dept. Ag.) 
 Fig. 82. — Aphis on apple. (Photo from Ohio Exp. Sta.) 
 
120 
 
 ORDER HEMIPTERA 
 
 fields, upon which the hce maintain themselves until corn 
 plants are available 
 
 This species aj)pears to become so comj)letely adapted 
 for underground life and the association with ants that it 
 does not necessitate producing any winged generation for 
 distribution or for alternation with another food plant. 
 
 On account, of this relation to ants, one of the measures 
 of control is to plow and harrow the ground thoroughly 
 
 Fig. 83. — Woolly aphis {Schizoneura lanigera): a, agamic female; b, 
 larval louse; c, pupa; d, winged female with enlarged antenna above; 
 all greatly enlarged and with waxy excretion removed. (From Marlatt, 
 Div. Ent., U. S. Dept. Ag.) 
 
 in order to break up the nests of the ants. This method 
 adopted in the autumn together with a wider cultivation 
 and destruction of weeds in the fields in spring will assist 
 in keeping the pest in check. Perhaps the most important 
 measure is a rotation of crops so that corn will not be culti- 
 vated for a number of years in succession on the same ground. 
 Woolly Apple Aphis {Sckizorievra lanigera). — The woolly 
 apple aphis is a very destructive species, its injury for the 
 
FAMILY APHIDID^ 
 
 127 
 
 most part being noted upon apple trees and is credited with 
 attacks both on the roots and trunks of some trees, Hmbs 
 or larger twigs near the ground. It is covered with a white 
 cottony substance and this tends to shed water. On the 
 
 Fig. 84. — Woolly aphis (Schizoneura lanigera) : a, root of young tree 
 illustrating deformation; h, section of root with aphides clustered over 
 it; c, root louse, female — a and h, natural size; c. much enlarged. (From 
 Marlatt, Div. Ent., Circ. 20, 2d series, U. S. Dept. Ag.) 
 
 roots it produces large knotty swellings and these injuries 
 cause serious effects upon the tree. Usually these insects 
 are observed in a wingless form but in the autumn some of 
 the individuals become winged and migrate to the elm, 
 
128 
 
 ORDER HEMIPTERA 
 
 where in the spring of the following season they produce 
 rosette galls, later migrating back to the apple. The rosette 
 gall has been separated from the leaf curl gall produced by 
 Schizoneura americana, a species that is a frequent pest on 
 elm trees. 
 
 Fig. 85. — Woolly aphis on apple twigs. (Photo from Ohio Exp. Sta.) 
 
 Remedies for the root form are difficult, but for orchard 
 trees after removal of the earth, sprinkle tobacco dust on 
 the roots and replace the soil. The use of 10 per cent, 
 kerosene emulsion can also be recommended. Above ground 
 
FAMILY ALEYRODID^ 129 
 
 the use of tobacco extract or 7 per cent, kerosene emulsion 
 may be used. 
 
 In another group of aphids we have the gall-making 
 pemphiginse which cause conspicuous deformations upon the 
 leaves of many different plants. Some of the more con- 
 spicuous ones are the vagabond gall on cottonwood, and the 
 poplar leaf galls. 
 
 Grape Phylloxera. — The Grape Phylloxera is one of the 
 very destructive insects of the grape-vine and is known over 
 a wide territory, having been carried from America to Europe, 
 where it caused a great deal of destruction to the vineyards, 
 especially in southern France. It affects the roots of the 
 vines and occurs on these during autumn, winter and early 
 spring, but during midsummer migrates to the leaves, caus- 
 ing the production of leaf galls, so conspicuous at that time. 
 By the time these galls mature or the leaves ripen the insect 
 migrates to the roots. The use of bisulphide of carbon 
 injected into the soil is the most available remedy, but there 
 is so much difference in the resistance of different varieties 
 of grape that the cultivation of thick-leaved kinds is con- 
 sidered advantageous. Where flooding is practicable, the 
 submergence of the insects for a period of two or three days 
 is effective. 
 
 Numerous species of phylloxera occur on the leaves of 
 hickory, walnut, and other trees, but for the most part are 
 not considered of especial economic importance. 
 
 Family Aleyrodidse — The next family in the series is the 
 AleyrodidoB. These are forms which have a mealy covering 
 on the wings and have the eyes divided, each compound 
 eye being divided into two, and the antennae being located 
 within the division of the eye. The adults are very similar 
 but the larvae and nymphs which form scale-like bodies on 
 trees have very distinct characteristics so that the species 
 are to be distinguished by the study of these stages rather 
 than of the adults. They resemble somewhat the scale in- 
 sects, but the adult characteristics are quite different. The 
 scales are quite distinctive. In many cases there is a fringe 
 of white, waxy material which seems to act as an attach- 
 9 
 
130 ORDER HEMIPTERA 
 
 ment to the surface of the bark. This often Hfts the scale 
 from the surface of the bark. There are cHstinct differences 
 in the markings of the body and in the anal plates. A rather 
 destructive form occurs on greenhouse plants, and is known 
 commonly by the name of "white fly." In some instances 
 it is very destructive. The eggs of the adults are laid on the 
 leaves and the larvae fix themselves after a short migration 
 and develop until they have reached the pupal, stage, and 
 from this stage the adult winged form issues. The family 
 is not so large nor so important as the scale insects — Coccidoe. 
 Two species occur on oranges in Florida; one, the orange 
 white fly, is often the means of serious loss in orange orchards. 
 They are treated by sprays and by cultivation of certain 
 parasitic fungi. 
 
 COCCIDiE. 
 
 The Coccidoe, scale insects, or bark lice, are to be considered 
 as the extreme branch along the line of specialization found 
 in this group. There are several subdivisions with various 
 kinds of specializations. The group is characterized by the 
 absence of wings in the females and the reduction of wings 
 in the males to one pair, they are usually firmly attached 
 to the plant on w^hich the larva has settled and even in 
 forms not attached probable means of migration are limited. 
 The males are winged but show distinct specialization in 
 the reduction of the second pair of wings. These constitute 
 simple, aborted, hook-like structures that can serve no pur- 
 pose in flight. The same kind of reduction as in Diptera. 
 The males also show a fairly distinct metamorphosis. The 
 larvae change to a quiescent pupal stage and this gives rise 
 to an adult two-winged male. The females are wingless 
 and usually immovable, mating depends entirely upon the 
 migration and flight of the males. 
 
 Owing to the extent and the economic importance of this 
 group, it seems desirable to give some account of the sub- 
 families and to discuss somewhat in detail certain of the 
 especially important economic species. Their sedentary 
 habits permit a ready distribution, yet make it easy to 
 
COCCIDM 
 
 131 
 
 control them by proper laws for exclusion. In determina- 
 tion, the appearance and color of the scale and the appear- 
 ance it gives to the trees are very important. There are 
 several subfamilies but the following include the American 
 species of importance. 
 
 The DactylopiinoB, including the mealy bugs and related 
 forms, differs from other members of the family largely in 
 the fact that the species are less fixed in habit. The mealy 
 
 Fig. 86. 
 
 -Orthezia solidaginis Sanders on goldenrod leaves, 
 author.) 
 
 (Photo by 
 
 bugs are particularly active and capable of traveling about 
 readily. They are covered with a whitish, mealy secretion 
 from which they derive their name, and in temperate regions 
 are found for the most part in greenhouses but there are a 
 few native outdoor species. The common mealy bug of 
 greenhouses {Psendococcus citri) is a very well-known pest 
 and may be found in different stages of its life history in 
 almost any greenhouse and frequently upon house plants 
 if kept where there is moisture. Fumigation and the use of 
 washes are available for their control. 
 
132 
 
 ORDER HEMIPTERA 
 
 An interesting subdivision of the group includes the 
 Orthcziince which secrete a white calcareous secretion which 
 appears in plates or filaments extending from the body, often 
 as long parallel bars extending back some distance from the 
 body. A rather common species in the Northern States is 
 solidaginis, occurring on goldenrod. There also is included 
 in this group the very destructive cottony cushion scale, 
 Icerya purchasi, which for a time threatened the fruit 
 
 Fig. 87. — Pulvinaria innumerabilis: adult females in position on twigs 
 with egg sacs — natural size. (Howard, Div. Ent., U. S. Dept. Ag.) 
 
 industry of California but which was brought under control 
 by the importation of the Australian lady bird (Vedalia 
 cardmalis) . 
 
 The subfamily Coccincp includes what are termed the soft 
 scales. The bodies of these are covered more or less com- 
 pletely with a waxy secretion which adheres firmly to the 
 body wall and furnishes a thick^ more or less rigid protec- 
 tion to the body. Most of them adhere fixedly to the bark 
 or leaves but in some cases a migration at the time of moult- 
 
COCCIDM 
 
 133 
 
 ing or when changing from the nymph to the adult stages 
 may occur. 
 
 Maple Scale (Puhinaria innumerabilis) . — The maple scale 
 is a wide-spread and occasionally abundant and destructive 
 species, attacking particularly the soft maple and occurring 
 at times on other trees or woody plants. In this species 
 the adults mature in autumn and winged males issue from 
 the scale and mate with the females, the latter remaining 
 
 Fig. 88. — Puhinaria innumerabilis: a, newly hatched young; h, female, 
 third stage, from above: c, same, from side; d, male, third degree; e, same, 
 natural size, on leaf and petiole; /, same, enlarged, on leaf petiole showing 
 two specimens parasitized, all greatlj* enlarged except e. (From Howard, 
 Buieau of Entomology, U. S. Dept. of Agriculture.) 
 
 unwinged. They may, however, migrate from leaves to 
 twigs or branches and attach themselves firmly for the 
 winter, which is passed by the adult female only. In spring 
 the eggs are developed and by early June a very large cottony 
 mass is formed beneath the scale, lifting it from the bark, 
 except at the anterior end, and within this large cottony 
 mass an enormous number of eggs are deposited. Hatching 
 of the eggs occurs shortly after the deposition and the larvae 
 
134 ORDER HEMIPTERA 
 
 travel rapidly for a day or two, going especially toward the 
 outer and upj>er branches where they fix themselves, and 
 during successive moults remain attached to leaf or bark 
 until autumn, when the a,dults mature, completing the life- 
 cycle. 
 
 Diaspinae. — The armored scales {Diaspiiioe) differ from 
 the i)receding forms in that the waxy secretion separates 
 from the body wall and forms an external shield or cover 
 within which the scale insect is enclosed and w^ithin which 
 there is soilie possibility of movements of parts, although 
 the mouth parts are anchored quite permanently in the 
 bark. Classification of the species in this division is com- 
 plicated by the presence of this external scale, although in 
 many species the external features of the scale are a fairly 
 good basis for the recognition of the species. 
 
 A microscopic examination is required to determine the 
 species in many cases. The pygidium (the fused terminal 
 segments of the abdomen of the female) includes the char- 
 acters most often used, as it is highly chitinous so that it 
 holds its peculiar characters even after a long time in a 
 dried state. Specimens kept dry twenty to thirty years 
 may be used for examination. The dorsal surface may have 
 glands that produce waxy secretion forming the scales. The 
 anal opening is also on the dorsal side. 
 
 Upon the ventral surface the vaginal opening is a con- 
 spicuous landmark and ordinarily grouped around this are 
 small spinnerets which appear under the microscope as 
 strongly chitinized circles. There are generally four or five 
 groups. These groups are named according to their relation 
 to the vaginal opening. The median or anterior group is in 
 front of the vaginal opening and on each side at about equal 
 distances are the cephalolateral or anterolateral group and 
 the caudolateral group. These spinnerets or grouped glands 
 are entirel}^ wanting in the San Jog6 scale. 
 
 The marginal structure of the pygidium takes second 
 place in the determination of species and the number and 
 shape and modification of the lobes are very important. 
 In some cases there are thickenings of the margin that closely 
 
COCCIDM 135 
 
 resemble the lobes. The incision of the margin by their 
 shape and extent afford characteristics of value. 
 
 Spines on the lobes are commonly present and afford quite 
 serviceable characters. There are generally two for each 
 lobe — one on each of the dorsal and ventral surfaces. In some 
 cases these spines are tubular and threads may sometimes 
 be seen issuing from them. 
 
 The plates are distinctly modified spines. They are gen- 
 erally flattened and frequently notched. The simple forms 
 differ from spines in that they do not have a globular base. 
 Wax ducts appear as hairs on spines which extend into the 
 body. 
 
 Chionaspis Salicis. — The willow scale {Chlonaspis salicis) 
 possesses a dense waxy structure overlying and separate 
 from the body of the insect. The mouth parts are imbedded 
 in the bark and sap wood. The head is pretty well marked 
 but antennae and legs are reduced. There are two entirely 
 different kinds of scales on the willow. The larger is an oval, 
 somewhat elongated scale, the smaller narrow and with 
 three rather fine ridges. The large scale is the female, the 
 smaller the male. The growth of scales takes place during 
 summer months; they increase in size by successive moults. 
 As the larval scale is shed it is left attached to the new scale, 
 and so on, often two or three are attached to the outer sur- 
 face of the scale. By autumn these will have reached 
 maturity, and mating will occur probably by early October. 
 The males all die off immediately and the females deposit 
 eggs and then shrivel up and die before winter. The female 
 never leaves the scale at all. 
 
 At the beginning of winter there is this mass of eggs 
 protected under a scale as the means of carrjdng the insect 
 over to the spring. They hatch probably during early June, 
 possibly the latter part of May. Eggs are reddish-purple. 
 The larvse crawl from under the scale and scatter out and 
 make a special effort it would seem to get on new twigs and 
 fresh growth of wood. They seem to travel upward in the 
 lightest direction and this naturally carries them out to the 
 ends of the twigs and leaves. During this migration period, 
 
136 ORDER HEM I PT ERA 
 
 which lasts two or three (hiys, they may be distributed in 
 several ways. A good breeze might carry them some little 
 distance. They may be carried by birds. They may be 
 carried on pieces of plant on which they occur, which is the 
 means bv which most of the scale insects are distributed. 
 
 
 
 Fig. 89. — Chionaspis furfurus. Scurfy scale on apple. (Photo from Ohio 
 
 Exp. Sta.) 
 
 Oyster-shell scale is named from the shape of its scale. 
 It is a European species, but occurs as a widely distrib- 
 uted species in this country and affects a number of host 
 plants, principally the apple. The adults mature in fall and 
 white eggs are deposited under scales and survive the winter, 
 hatching early in June. The larvae then scatter and develop 
 during the summer. 
 
COCCID^ 137 
 
 San Jose Scale. — The San Jose scale is an introduced 
 species which has been the source of an immense amount of 
 loss in orchards, nurseries, etc. It presents some modifica- 
 tions from the ordinary forms. It is small with an almost 
 perfectly circular scale. The exuviae remain near the centre, 
 giving it a somewhat nipple-shaped appearance. When 
 
 Fig. 90. — San Jose scale: male adult — greatly enlarged. (After 
 Howard.) 
 
 abundant they give a very scurfy incrusted appearance to 
 the twig on which they occur. The male scales are smaller 
 and a little more oval in shape. The life history differs from 
 most other species in that young are produced alive, the 
 eggs hatching before extrusion, and the young develop 
 rapidly, mature in a short time, and produce another genera- 
 tion. There may be as high as four to six generations in a 
 
138 
 
 ORDER HEMIPTERA 
 
 season. It has been estimated that a single female may be 
 the parent of about three and a half billions in a single 
 season. Since there is no egg, but young are brought forth 
 alive, they must have constant nutrition, and unless the scale 
 is attached to living tissue the insects must perish, except 
 
 / 
 
 A / 
 
 / 
 
 '\ 
 
 / 
 
 ■f{ 
 
 ) 
 
 \ .. 
 
 \ 
 
 '--a.*?. \^iv ' 
 
 
 
 N' 
 
 c 
 
 
 
 ''"-\ 
 
 
 
 
 
 tli 
 
 d 
 
 
 Fig. 91. — San Jose scale: c, adult female containing young — greatly- 
 enlarged; d, anal fringe of same — still more enlarged. (After Howard.) 
 
 that mature females may assume a dormant condition dur- 
 ing cold weather. The only means of transportation to 
 distant points, therefore, appears to be upon living plant 
 tissue, and this makes it possible to prevent its distribution 
 by adopting restrictive measures through inspection and 
 quarantine. 
 
COCCIDM 
 
 139 
 
 For measures of treatment where exclusion is not possible, 
 there are two or three fairly effective remedies in the killing 
 of the scale. One of these is kerosene emulsion, made by 
 agitating kerosene and soapsuds. One gallon of water, 
 
 Fig, 92. — San Jose scale on leaves and fruit. (Photo from Ohio Exp. Sta.) 
 
 one-half pound of soap brought to the boiling point and then 
 mixed (away from the fire) with two gallons of kerosene 
 and then agitated into an emulsion by a force-pump or egg- 
 beater. This is diluted with soft water, one part of emul- 
 sion to eight or nine parts of water. 
 
140 
 
 ORDER HEMIPTERA 
 
 Whale-oil soap is sometimes used, but the most favored 
 remedy at the present time is lime-sul])hur wash formed by 
 boiling the ingredients together. This is applied by means 
 of a spray-pump so that it covers the trees. If these appli- 
 cations are made thoroughly the scales may be killed off to 
 a great extent, though it is is hard to completely exterminate 
 them. Badly infested trees will seldom recover and it is 
 about as well to cut out and destroy such trees. Remedies 
 that can be applied when larvae are travelling will be more 
 effective, but in San Jose scale larvae are travelling most of 
 the summer months. In those species where there is a 
 
 Fig. 93. — Peach orchard injured l)y San Jose scale. Neglected, badly 
 infested orchard at right and injured rows adjacent in spite of careful 
 spraying with protection to rest of orchard at left. (Photo by author.) 
 
 definite period for the larvae, spra^^ing even with clear water 
 if the pressure is great w^ill reduce their numbers considerably. 
 It is important to know the life histories perfectly. 
 
 The Heteroptera include those forms which have wings 
 thickened at the apex and in which the mouth parts arise 
 from the most anterior portion of the head, and both in this 
 character and in the wing structure are evidenth^ more 
 specialized than the Homoptera. It is not possible to say 
 that any of the Heteroptera present more specialization in 
 certain lines than some of the Homoptera. 
 
 The families are pretty well marked, and a number of 
 
CORISIDyE 141 
 
 the groups are aquatic, a number terrestrial, and some 
 arboreal. The aquatic forms are derived from the terres- 
 trial. Most of them are obhged to come to the surface of 
 the water to secure air at various intervals and this shows 
 that they are modified from terrestrial forms. The aquatic 
 forms pass the larval stage in the aquatic life but in most of 
 the aquatic families the adults are also aquatic, though they 
 may issue from the water and fly readily out of water. The 
 eggs of aquatic forms are deposited on aquatic plants dis- 
 tributed in the water and only in a few cases do they show 
 marked peculiarities in the matter of egg deposition. In 
 one of our common species, the smaller water bug {Zaitha 
 flwninea), the eggs are deposited on the back of the male 
 
 c h a 
 
 Fig. 94. — Water bugs: a, water boatman, Corisa harrisii; b, Notonecta 
 
 irrorata; c, Notonectaundulata. Enlarged X 1.42. (Photo by C. J. Drake.) 
 
 by the female in a rather large mass, the eggs being set on 
 end attached to the wing covers and are carried in this way 
 for some time until they hatch. 
 
 Of the terrestrial forms there are a considerable number of 
 families. Some important species, chinch bug, squash bug, 
 etc. The effect of the chinch bug on cereal crops is very 
 damaging. 
 
 Water Boatmen (Corisidce). — The water boatmen are small 
 species. Their legs are modified for swimming, the hind 
 ones being long, wide, and oar-like, having a series of cilia 
 which aid much in swimming. The species are found in large 
 numbers in ponds and streams, occasionally they fly in large 
 swarms. Spring is the usual time when they are seen flying 
 
142 ORDER HEMIPTERA 
 
 and are attracted very much by lights. They constitute a 
 food supply for fishes and they themselves feed on other 
 aquatic organisms. One species in Mexico is dried and used 
 for food by the natives and is also sold in the markets as 
 bird food. There is some question as to their economic 
 importance. 
 
 Notonectidse. — ^These are generally larger than the Corisidce. 
 The striking thing about them is that they swim back down- 
 ward, coming to the surface of the water at intervals for air. 
 Our common species is Notonecta undidata. This species 
 has a severe bite and it is best to handle it with care. 
 
 Water Scorpions (Nejndce). — The water scorpions are 
 characterized by a long respiratory tube at the end of the 
 body; a very much elongated coxa in the forelegs so that 
 the femur and tibia can be thrust out from the end of the 
 body to catch prey. They are generally found in shallow 
 water, secreted in dead leaves close to the bottom. How- 
 ever, they are strictly dependent on air for respiration and 
 get it by sticking this respiratory tube up to the surface of 
 the water. They are strictly carnivorous, puncturing their 
 prey and sucking the blood. If they are touched they feint 
 and their legs may be broken off without any motion on 
 their part. 
 
 Belostomidae. — These are the giant water bugs and are the 
 largest bugs belonging to this order. They have a short 
 respiratory tube and a strong and somewhat curved beak, 
 and can inflict a very severe bite. They are quite preda- 
 ceous, feeding on young fish, and sometimes even those 
 larger than themselves. Thus they are of distinct impor- 
 tance as destroyers of fish. They go through all the stages 
 of their life-cycle below the surface of the water. The eggs 
 are laid under water on the stems of plants or in the case 
 of one species on the back of the insect itself. The eggs 
 are cemented so tightly that sometimes the shells remain 
 long after the eggs are hatched. The young at first are 
 nearly the form of the adults but without wings. They 
 grow by successive moults and with gradual appearance of 
 wing pads until they reach the adult stage. 
 
BELOSTOMIDM 
 
 143 
 
 Two species, one found in the Philippines and the other 
 in South America, are much larger than those found here. 
 
 Fig. 95.— Water scorpion {Ranaira americana). (Drawn by Jos. D. Smith.) 
 
144 
 
 ORDER HEMIPTERA 
 
 There are two large species commonly found in the United 
 States, the Bclestoma americana, which has a groo\'e along 
 the inner margin of the forefemur, while the Benacu.s' griseus 
 has none. The latter is also slightly larger, has the hind 
 tibiae broader and the legs not so distinctly annulated with 
 dark rings. 
 
 Fig. 96. — Giant water bug (Benacus griseus Say) : dorsal and ventral 
 views. Slightly enlarged. (Original photo by C. J. Drake.) 
 
 Water Striders (IlydrohaficloB). — This is a very interesting 
 group. Their bodies are covered with a very fine velvety 
 coat which sheds water, thus enabling them to live on the 
 surface of water. They look somewhat like spiders, the 
 legs are long and extend outward in a spider-like manner. 
 The front pair are shorter than the others, being used to 
 catch food. The antennse are short and are hard to dis- 
 tinguish from the first pair of legs. Along with these forms 
 
REDUVIID^ 145 
 
 there are several little shore-living species, of no economic 
 importance, however. 
 
 Predaceous Bugs. — The Assassin Bugs {Reduviidw). — 
 The assassin bugs are rather large-sized insects with slender 
 bodies and legs. The beak is rather strong and short and 
 
 Fig. 97. — Water strider {Limnogonus hesione). (Drawn by Jos. D. Smith.) 
 
 is fitted for punctm'ing insects. The species generally are 
 predaceous, feeding very largely on destructive insects. 
 Several species, however, puncture warm-blooded animals 
 and suck their blood. The most familiar one of this kind 
 is the "kissing-bug" or blood-sucking cone-nose. This 
 is a strictly Southern species and is rarely found north of 
 
 10 
 
146 
 
 ORDER HEMIPTERA 
 
 of the Ohio Ri\'er. It occurs in the Southern States and 
 occasionally in Ohio. The masked bed-bug hunter is com- 
 
 FiG. 98. — Blood-sucking cone-nose {Conorrhinus sanguisugus) : h, nymph; 
 c, adult. Enlarged. (From Bur. Ent., U. S. Dept. Ag.) 
 
 Yi(j^ 99. — The " kissing- bug " or masked bed-bug hunter (Redurius perso- 
 natus). (After Howard, Div. Ent., U. S. Dept. Ag.) 
 
 mon in both Europe and America. The wheel bug, so-called 
 on account of the round thorax, is also found in the South. 
 
ACANTHIDM 
 
 147 
 
 The thread-legged bug is a very thin insect which, like 
 the water scorpion and praying mantis, has the coxa of the 
 front legs elongated for grasping. The damsel bugs {Nahid(B) 
 are serviceable in eating leafhoppers and like pests. While 
 the ambush bugs {Phymatidoe) are serviceable in reducing 
 the number of destructive insects, they also show protective 
 coloration to' a marked extent. Phymata erosa is our common 
 species. It is commonly found in blossoms of goldenrod or 
 other plants where it catches insects which visit the flowers. 
 
 The Bed-bug Family (Acanthidce) .—These bugs are much 
 flattened and are pretty generally predaceous or blood- 
 sucking. The most common species, bed-bug {Cimex lectu- 
 
 FiG. 100. — Phymata erosa: a, dorsal view; h, lateral view; c, front leg; 
 d, snout— a, b, enlarged; c, d, more enlarged. (Riley, Div. Ent., U. S. 
 Dept. Ag.) 
 
 larius), is restricted to houses and is quite largely dependent 
 upon human blood for food. It is almost entirely wingless, 
 the wings being very small, owing to disuse, and thus beconi- 
 ing entirely useless as organs of flight. This species is 
 distinctly averse to light and hides during the daytime m 
 cracks and crevices, coming out at night to feed. They are 
 light colored when young and become darker with growth, 
 and appear darkest just after a meal, which consists of blood. 
 The feeding periods are far apart and the species is able to 
 live for a long period without any supply of food. It is said 
 that one can live a year without food. They cannot crawl, 
 and depend upon being carried from place to place on cloth- 
 ing. They are commonly found in cheap hotels and board- 
 
148 
 
 ORDER IIEMIPTERA 
 
 ing liouses and wlien once established in a place it is very 
 difficult to get rid of them. The life history of the species 
 is not very definitely known. 
 
 The eggs, which are deposited upon furniture and in cracks 
 and crevices, are white and rather long and cylindrical. 
 They hatch in a few days, the young are of the same shape 
 as the adult but are white. The young bugs moult five or 
 six times before they are mature. The growth is very slow 
 
 
 Fig. 101. — The bed-bug (Cimex lectularius) : a, adult female gorged with 
 blood; h, the same from below; c, rudimentary wing pad; d, mouth parts. 
 a and h much enlarged; c and d, highly magnified. (Marlatt.) Relapsing 
 fever and kala azar are carried by the bed-bug. (Rosenau.) 
 
 and irregular, all depending upon opportunities offered for 
 getting food. This species does not have a regular life-cycle 
 as insects which live out of doors under the influence of the 
 seasons. Bed-bugs can be killed with sufficient effort, cor- 
 rosive sublimate being one of the best remedies. Kerosene, 
 gasoline, or hot water prove very effective. Constant 
 attention to furniture and the destruction of those bugs 
 which appear is the most essential thing in their destruction. 
 Bed-bugs are of considerable importance from the fact that 
 
CAPSIDM 
 
 149 
 
 Fig l^2.-Coauilleiia mimetica Osborn: a female dorsal jiewjb female 
 (After Osborn. From drawings by Miss Kmg.) 
 
150 
 
 ORDER HEMIPTERA 
 
 they have the power of transmitting blood diseases from 
 one person to another. 
 
 The Tingitid(B, or lace bugs, are common on thorn bushes, 
 sycamore, oak, walnut, and many other plants. 
 
 The leaf bugs {Capsidm) are of some economic importance, 
 from the fact that they attack the leaves of fruit trees in 
 
 Fig. 103. — Sericophanes ocellatus Reut: dorsal views: a, macropterous 
 male; b, micropterous female; c, macropterous female; d, side view microp- 
 terous female; e, macropterous female; /, wing of micropterous female; g, 
 micropterous female; h, male abdomen beneath. (After Osborn. Drawn 
 by Miss C. M. King.) 
 
 the spring, puncturing them and sucking the plant juices. 
 They are also quite common in meadows and pastures. 
 
 The tarnished plant bug is a very important species 
 affecting orchards where it attacks the buds and blights 
 them. It also works on clover and does great damage to 
 strawberries, causing ''buttoning." 
 
 Certain species in this family show a very strict resem- 
 
LYGAEID^ 151 
 
 blance to ants, and this is especially so in the case of the 
 species of Pilophorus, Coquilletia, and Sericophanes, 
 
 One of these species, Coquilletia mimetica, carries this 
 resemblance to the extreme in the development of small 
 elevations on the first and second abdominal segments 
 which correspond closely to the first abdominal segment of 
 the ant. The female in one form is entirely wingless, but a 
 full-winged form of female also occurs, and the males are 
 full-winged. 
 
 Another species, Sericophanes ocellatus, shows somewhat 
 less modification in that the wings are not completely lost 
 
 Fig. 104. — Chinch bug (Blissus leucoptcrus) : adult of long- winged form, 
 much enlarged. (From Webster, Div. Ent., U. S. Dept. Ag.) 
 
 but are retained as short rudiments which extend over 
 the basal segments of the abdomen. The effect as a whole, 
 however, closely simulates the appearance of an ant. 
 
 The family Lygaeidse includes the chinch bug and numer- 
 ous other small bugs, but few of which are of economic 
 importance. 
 
 Chinch Bug {Blissus leucopterus) . — ^The chinch bug is very 
 important as a farm pest. It has a long, slender body with 
 parallel sides and four-jointed antennae. The body is black 
 and the wings white. It occurs all over the Mississippi 
 Valley and south to Central America but it is most serious 
 
152 
 
 ORDER HEMIPTERA 
 
 in Illinois, Missouri, Kansas, Nebraska, Iowa, and parts of 
 Indiana, and occasionally in parts of Ohio. The losses due 
 
 Fig. 105. — Chinch bug: a, b, eggs; c, newly hatched larva or nymph; 
 d, its tarsus; e, larva after first moult; /, same after second moult; g, last- 
 stage larva; the natural sizes indicated at sides; h, enlarged leg of perfect 
 bug; j, tarsus of same, still more enlarged; i, proboscis or beak, enlarged. 
 (From Eiley.) 
 
 to this insect are large, being estimated as high as $60,000,000 
 and amounting to $20,000,000 in one State alone in one year. 
 
 Fig. 106. 
 
 -Chinch bug. Adults of short-winged form, much enlaiged. 
 (Alter Webster, Bur. Ent., U. S. Dept. Ag.) 
 
 It has two generations a year and the winter is spent in 
 the adult stage under bark of trees, bunches of grass, fence 
 corners, etc. Often if a thicket is near they will migrate 
 
LYGAEIDM 
 
 153 
 
 to it. In the prairies they hide in the grass and emerge in 
 the spring. The female begins to deposit eggs in April and 
 May. This is done gradually and extends over a period of 
 about three weeks. This early deposition is usually done 
 about one-half inch under the ground on the stems of spring 
 or winter wheat. The eggs are white and very minute and 
 have four little projections at the head end. They hatch 
 in three or four days after deposition, into minute little 
 
 Fig. 107. — Chinch bug on corn. (Photo from Ohio Exp. Sta.) 
 
 white bugs with small red spots, having the same shape as 
 the adult but lacking in wings.. They are unable to feed on 
 plants outside of the grass family, migrate to corn after the 
 wheat is cut and while some have wings fully developed they 
 usually all move on foot. At this time they can be easily 
 killed. The eggs of the second brood are laid on the corn 
 stalks. Before cold weather comes there is an extensive 
 migration, probably accompanied by mating, and the insects 
 hibernate. One group matures in the summer and dies while 
 
154 ORDER HEMIPTERA 
 
 the second groui) matures and liihernates and produces a 
 spring brood. 
 
 The control of the chinch bug is based on tlie use of barriers 
 between the wheat fiekls and the corn, and a dust furrow 
 is good, or the placing of a crop that they will not feed on, 
 
 Fig. lOS. — Chinch bug. (Photomicrograph from Ohio Exp. Sta.) 
 
 such as potatoes, between the corn and wheat. When the 
 bugs first go into the corn they stop on the first few rows 
 and when there they may be killed with kerosene emulsion. 
 Rotation of crops is a good thing and the burning of waste 
 grass and weeds in the late fall gets those that live there. 
 
COREIDM 
 
 155 
 
 They may be ploughed under in the stubble but this must 
 be at least five inches deep. The introduction of a fungus 
 which was fatal to the bug was tried extensively but without 
 success sufficient to warrant its recommendation as a reliable 
 measure of control. 
 
 Family Coreidae. — This family includes the squash bug 
 and a number of other prominent species. They are dis- 
 tinguished by the robust body, numerous veinlets in the 
 membrane and the four- jointed antennae. The common 
 
 
 ^^sf^' ^ 
 
 Fig. 109. — Chinch bug. Hibernating quartors. (Photo from Ohio 
 Exp. Sta.) 
 
 squash bug is a very familiar species, a large dark colored 
 insect about three-fourths of an inch long. It hibernates 
 in adult form secreted around buildings or under debris on 
 the surface of the ground and in early summer deposits eggs 
 on squash or melon vines. The nymphs puncture the leaves, 
 and their attack upon the plant often results in a complete 
 withering, so that if the insect is numerous the crop may be 
 seriously affected. The eggs are small glistening objects 
 attached in loose clusters upon the under side of the leaf. 
 
150 
 
 ORDER IIEMIPTERA 
 
 The nymphs are at first without trace of wing pads, but in 
 successive instars the wing pads increase in size. The 
 different instars are sliown in the accompanying figure. 
 
 Fig. 110. — Anasa tristis: a, mature female; h, side view of head, show- 
 ing haustellum; c, abdominal segments of male; d, same of female; a, 
 twice natural size; b, c, d, slightly more enlarged. (From Chittenden. 
 Div. Ent., U. S. Dept. Ag.) 
 
 Fig. 111. — Anasa tristis nymphs: a, newly hatched; b, second stage; c, 
 third stage; d. fourth stage; e, fifth stage — all about twice natural size. 
 (From Chittenden, Div. Ent., U. S. Dept. Ag ) 
 
 Box Elder Bug {Leptocoris trivittatus) . — The box elder bug 
 is black with red lines, and since this species has been migrat- 
 
COREIDJE 
 
 157 
 
 ing eastward from an original westward habitat it is of 
 interest to note its progress. In recent years it has been 
 observed as far east as Ohio and it is quite likely to extend 
 
 Fig. 112. — Eggs of Anasa tristis: o, from below, showing point of attach- 
 ment; b, from side, showing place of escape of nymph; c, sculpture of egg; 
 d, egg cluster; a, b, about five times natural size; d, one-fourth enlarged; 
 c, greatly enlarged. (From Chittenden, Div. Ent., U. S. Dept. Ag.) 
 
 Fig. 113. — Leptocoris trivittatus: a, eggs enlarged, natural size above, 
 b, c, d, different stages of immature bugs; e, adult; all enlarged; natural 
 sizes indicated by hair lines. (All after Marlatt except e, which is after 
 Howard, Div. Ent., U. S. Dept. Ag.) 
 
15S 
 
 ORDER IIEMIPTERA 
 
 its range to the Atlantic coast. It attacks particularly box 
 elder trees and the young probably feed upon this in prefer- 
 ence to other plants, but the adults in autumn scatter quite 
 widely and in some instances are quite troublesome in 
 
 Ficj. 114. — Corizus crasaicornis. (After Hambleton.) 
 
 houses because of their tendency to fall into all kinds of 
 objects such as milk pans and other food receptacles. 
 
 The species of Corizus are small, robust forms occurring 
 on a very great variety of plants and commonly noted along 
 roadsides and in clover fields. 
 
PENTATOMID^ 
 
 159 
 
 Stink Bugs (Pentatomidce) . — Stink bugs are rather broad 
 oval-shaped insects with four- or five-jointed antennae, the 
 wings He flat and the membranous tip of the second pair 
 are uncovered. They have a rather large scutellum lying 
 between the bases of the wings. The characteristic odor of 
 the stink bugs is not confined to this particular family. A few 
 members of this family are of economic importance. The 
 green soldier bug is very destructive to peaches in the northern 
 part of the United States. The spined soldier bug (Podisus 
 
 Fig, 115. — The spined soldier bug {Podisus maculiventris) : adult at left, 
 nymph at right; much enlarged. (Chittenden, Div. Ent., U. S. Dept. Ag.) 
 
 maculiventris) is not very large and is characterized by very 
 distinct spines which project from the side of the body. 
 It is very distinctly a predaceous bug. It is credited with 
 killing the larvse of the Colorado potato beetle, and it also 
 feeds on caterpillars and other insects. On the whole it is 
 counted as being very beneficial. 
 
 The harlequin cabbage bug {Murgantia histrionica) is 
 one of the species common in the Southern States, and if it 
 becomes abundant is a very serious pest. Ohio is its northern 
 
160 
 
 ORDER HEMIPTERA 
 
 limit. It can be controlled by spraying with kerosene emul- 
 sion during the larval stage. 
 
 The subdivision Parasifa includes the suctorial lice, and 
 they present perhaps the greatest divergence from the 
 normal form, the extreme being in the direction of reduction 
 due to parasitism. They are entirely wingless; they have 
 a reduction of the mouth parts which is extreme. The beak 
 
 Fig. 116, — Stink bug: a, adult; b, eggs attached to leaves; c, d, e, f, 
 details of egg structure. (Bur. Ent. U. S. Dept. Ag.) 
 
 is reduced to a single segment through w^hich the tubular 
 setae are projected — a derivation from the three- or four- 
 jointed beak of the normal forms. There is a distinct 
 reduction or retrogression in the wings and mouth parts, 
 but a distinct specialization in the structures by which 
 they clasp the hairs or feathers of host forms. Tarsal claws 
 are very large and strong and are provided with ridges or 
 roughened areas which seem to strengthen the hold upon 
 
PARASITA 161 
 
 the hairs, and in a few forms there are still other speciaHzed 
 clasping structures to strengthen this hold. In some the 
 antennae serve to help hold on. In one form there is a 
 tubercle developed so that it fits against the pair of legs 
 next forward so that it seems to act as a clasping organ. 
 These suctorial lice are limited to mammals for their hosts. 
 The mouth parts are doubtless adapted to the reaching of 
 the capillary blood system in these hosts and in their life 
 history they show adaptation to the parasitic habit, the eggs 
 being glued to the hairs, the larvse on first hatching being 
 capable of attaching themselves to the hairs so that the 
 entire life-cycle is distinctly parasitic. Their migrations 
 from these host forms are simply for the purpose of scatter- 
 ing to other individuals of the same species. There is a 
 rather distinct tendency for the individuals to migrate to 
 younger animals of the same species. There is not a very 
 evident series of broods in a year — they probably breed 
 rather promiscuously. They have a constant host and 
 constant warmth. Three species affect man and the horse, 
 ox, sheep, hog, dog, and a great number of other mammals 
 are known to support one or more species. 
 
 Short-nosed Ox Louse {Hcematopinus eurysternus Nitzsch). 
 — The short-nosed ox louse is the common species occurring 
 on cattle. The full-grown females are about one-eighth 
 to one-fifth of an inch long, and fully that in wi^th, while 
 the males are a little smaller and proportionately a little 
 narrower. Aside from the difference in size the sexes differ 
 very decidedly in the markings and structural features upon 
 the under side of the body. The female is bluish leaden or 
 gray in color. The males have a broad black stripe running 
 forward from the end of the body to near the middle of the 
 abdomen, as shown in Fig. 117. The females have no 
 indications of this stripe, but the black, broken band of the 
 upper side of the terminal segment extends slightly around 
 on the under side. The most important character, however, 
 is the presence of two little brush-like organs on the next 
 to the last segment, as shown in Fig. 117. 
 
 The head is bluntly rounded in front, nearly as broad as 
 U 
 
162 ORDER HEMIPTERA 
 
 long, and witli the antennjv situated at the sides midway 
 from tlie posterior to the anterior })orders; behind these 
 are located slight eminences upon which may be found the 
 small eyes, which are seen with considerable difficulty. At 
 the front of the head may be seen the small rostrum or beak, 
 the end of which is usually near the surface, but which is 
 capable of extension or retraction. The end of this beak is 
 armed with a double row of recurved hooks (see Fig. 115). 
 
 Fig. 117. — Hoematopinus eurysternus: a, female; h, rostrum; c, ventral 
 surf are of the last segments of the male; d, same of female; e, egg; /, surface 
 of same greatlv enlarged. (Author's illustration, Bur. Ent., U. S. Dept. 
 Ag.) 
 
 Hog Louse {Hoematopinus vrivs). — The hog louse is one 
 of the largest species of the family, full-grown individuals 
 measuring a fourth of an inch or more in length. It is of a 
 gray color, with the margins of the head and thorax and 
 most of the abdomen dark. The head is quite long, the 
 sides nearly parallel, with strong eminences just back of 
 the antennae, which are set on the sides of the head, midway 
 from rostrum to occiput; the legs are lighter, with dark 
 bands at the joints; the spiracles are inclosed by a black 
 
PARASITA 
 
 163 
 
 chitinous eminence, and there is a broad black band on the 
 last segment, broken near the middle. (See Fig. 118.) 
 
 The male has the abdomen marked beneath with a large 
 black area extending forward from the end of the terminal 
 segment, so as to occupy the central portion of the last 
 three se2:ments. 
 
 Fig. 118. — Hcematopinus urius: a, female; b, ventral view of posterior 
 segments of male; c, leg, showing protractile disk of tibia — enlarged. 
 (Author's illustration, Bur. Ent., U. S. Dept. Ag.) 
 
 A curious provision is found in the feet for strengthening 
 the hold upon the hair. It consists of a circular pad-like 
 organ or disk in the outer portion of the tibia, which is 
 received in a conical cavity in the end of the tibia, and which 
 can be forced out so as to press upon the hair held between 
 the claw of the tarsus and the end of the tibia. 
 
164 ORDER HEMIPTERA 
 
 On account of the thinness of the hair, the application of 
 remedies, where necessary, is quite eas}^ Washes of tobacco 
 water or dilute carbolic acid, and the application of kero- 
 sene in lard, or kerosene emulsion by means of a force pump, 
 sulphur, ointment, etc., are recommended. The application 
 of fine dust may be provided for naturally by allowing the 
 hogs a chance to roll in a roadway or any place well supplied 
 with fine dust. Where this is impracticable the dust, ashes, 
 or powdered charcoal may be applied directly to the neck and 
 back of the infested animal. The species is not known to 
 attack any other of the domestic animals, and hence no pre- 
 cautionary measures in this direction are necessary. 
 
CHAPTER VI. 
 
 NEUROPTERA AND ALLIES. 
 
 The insects with complete metamorphosis include first 
 the Neuroptera which are represented by the lace-winged 
 fly, ant lion, etc. These are separated from the preceding 
 groups by the fact of the complete metamorphosis, and this 
 order includes groups which are quite distinct from each 
 other and have biting mouth parts and rather densely net- 
 veined wings. 
 
 Order NEUROPTERA. 
 
 Of the first family SialidcB, the Corydalis cornuta is the 
 most prominent. The larvae live in running streams and 
 under stones. Their structure and life-cycle furnish a 
 good example for the group. The larva is strictly aquatic 
 with gills which enable it to live in the water, but it can sur- 
 vive out of water if the gills are moistened. The adults 
 appear in the summer, mainly in the early part of summer, 
 and the eggs are laid during the summer months, generally 
 about midsummer, and deposited in large masses on the 
 leaves of trees overhanging water. The larvae on hatching 
 drop at once into the water and begin an aquatic existence. 
 They feed on the larvae of other aquatic insects, and their 
 life-cycle occupies three years. They are in the water for 
 about two years and eleven months; the pupa stage, passed 
 in muddy banks, as well as the adult stage being short. 
 The larva changes to a pupa which is quite different from 
 the larval stage and different also from the adult. They, 
 are counted excellent as fish bait, and this is perhaps their 
 most direct economic value. 
 
 The Mantispidce have very prominent front feet, wings lie 
 flat over the back and resemble a small form of the mantis. 
 
 The family Chrysopidoe, which includes the lace-winged 
 
 (165) 
 
166 
 
 NEUROPTERA AND ALLIES 
 
 flies, lias quite a ditt'erent larval hahit, Ix'ing carnivorous but 
 not aquatic. Lar\';e are fre(iuently called the "aphis lions" 
 as they are destructive to aphids. They are most commonly 
 found on trees on which a])hids are abundant. 
 
 Fig. 110. — Corydalis cornuta, female. (Photo by autlior.) 
 
 The adults are very delicate with very thin, transparent, 
 irridescent wings; brilliant golden eyes which stand out 
 prominently (therefore called golden eyes) ; wings closely 
 net-veined and bodies slender and cylindrical. The eggs are 
 
ORDER NEUROPTERA 
 
 167 
 
 deposited on leaves or twigs and are elevated on stalks, 
 each egg standing up on a very distinct thread or pedicle. 
 This is considered to be for protection of eggs from newly 
 
168 
 
 NEUROPTERA AND ALLIES 
 
 hatclied larvae of the same colony. The eggs are deposited 
 in this way by the adult touching the abdomen to the sur- 
 face of the leaf, then raising it quickly so that a thread of 
 glutinous secret'on is drawn out. This hardens quickly 
 and the egg is left at the tip of the thread. The larvae on 
 
 Fig. 121. — Chrysopa oculata: newly hatched larva, with under side of 
 head and claw at side — greatly enlarged. (From Marl alt, Di\. Ent., U. 
 S. Dept. Ag.) 
 
 hatching eat up the plant lice in the immediate vicinity. 
 They are active and run about readily and have prominent 
 jaws which are sickle-shape, tubular, and adapted for suck- 
 ing the body fluids of the plant lice. When they have passed 
 the larval stage they form a small spherical cocoon in which 
 they pass the pupa stage and from which the adults emerge 
 
ORDER MECOPTERA 169 
 
 shortly afterward. They produce a number of generations 
 each year. 
 
 Ant Lions {Myrmeleonidw) . — The ant Hons are closely 
 related to the preceding. They look much tne same, and 
 the only difference is the large antennae which stand out 
 and are thickened at the tip. They have large, equal-sized 
 wings and long, cylindrical abdomens. The wings are dis- 
 tinctly net-veined. These ant lions appear in midsummer 
 as adults and eggs are deposited presumably in the latter 
 part of the summer. Whether they pass the winter in the 
 egg stage or whether the larvse are partially developed is 
 uncertain. But during the early part of the season and a 
 large part of the summer the larvae may be found in sandy 
 places forming little pits in the sand in the bottom of which 
 they secrete themselves for the capture of ants and other 
 small animals which may wander into the pits. They travel 
 backward in changing their location, moving just beneath 
 the surface and leave a very definite furrow on the surface 
 of the sand. At one end of the furrow is usually a pit where 
 the larva is secreted. After acquiring their growth they 
 build a little spherical cocoon and within this they change 
 some time later to the chrysalis stage. The adult stage is 
 reached in, possibly, a two-year cycle. 
 
 Order MECOPTERA (Scorpion Flies). 
 
 In this order the species are usually four- winged, although 
 in some cases the wings are reduced or aborted. The wings 
 when occurring are not folded, have numerous veins, and 
 often are marked with distinct spots or blotches. The head 
 is much modified, being elongated so as to form a sort of beak 
 at the end of which are the small mandibles and the other 
 mouth parts. The metamorphosis is complete and the larval 
 stage is somewhat caterpillar-like in general structure. 
 
 The order includes the family Paiiorjndce and in this 
 family are a number of common species, but few of them have 
 any particular economic importance. They have usuall}^ 
 eight pairs of prolegs or abdominal legs so that the}^ may 
 
170 NEUROPTERA AND ALLIED 
 
 l)e (listinguislRMl from the l{'])i(l()])t(T()Us hir\'{i' which liave, 
 as a rule, only five pairs. 
 
 The s])ecies of liiffaru.s are somewhat common, usually 
 found in woodland, and lia\'e some resemblances to the 
 crane flies, but are easily distinguished by the presence of 
 four wings. The genus Borcus is remarkable for appearing 
 in the winter time and occurring in great numbers on the 
 surface of snow. 
 
 Order TRICHOPTERA (Caddice Flies). 
 
 This order is of particular interest scientifically because 
 it appears to be the primitive group from which the order 
 Lepidoytera has been derived. The mouth parts are man- 
 dibulate, the metamorphosis is distinct, the larval forms 
 caterpillar-like but all the species are aquatic and show 
 distinct specialization for aquatic existence. In the adults 
 the body and wings are covered with minute flattened or 
 scale-like appendages which approach the condition found 
 in the Lepidoptera and except for the mandibulate mouth 
 parts the group may be considered as distinctly connected 
 with the Lepidoptera. In some forms the wings are opaque 
 and the general appearance is extremely like some of the 
 minute moths. 
 
 Perhaps the most notable feature in the group is the 
 larval habit of forming cases or tubes within which they live. 
 These cases are made of a variety of materials, in some 
 species from minute pebbles, minute mollusk shells, and in 
 many cases w^ith fragments of aquatic plants or various kinds 
 of debris occurring in the water. The cases are constructed 
 shortly after the larvse hatch and are enlarged with the 
 growth of the insect. The head and thoracic legs are 
 projected from the tube, and the tube moved around by its 
 adherence to the posterior part of the body. Some species 
 have a habit of making delicate nets or traps in the water 
 by means of which they catch aquatic animals for food, 
 but in most of the species the larvse travel around freely and 
 feed upon aquatic vegetation. The tubes or caddices formed 
 
ORDER TRICHOPTERA 171 
 
 by these insects have been found in rocks of the tertiary 
 period, so that it may be assumed that the aquatic case- 
 making habit had developed as far back as this period 
 in geological times. Aside from the fact that these may 
 furnish food for other aquatic organisms there is little 
 economic importance to be attached to them. The adults, 
 while occurring in abundance, do not feed upon any culti- 
 vated crops, and they rarely appear in such swarms as the 
 May flies, so that there is no especial annoyance from their 
 abundance. 
 
CHAPTER VII. 
 COLEOPTERA. BEETLES. 
 
 The Coleoptera, or the order of beetles, is one of the immense 
 groups of insects, both in species and individuals. It is also 
 one of the most distinctly marked groups. In some ways 
 it is more specialized, in others more generalized. The 
 wing structure is specialized, the horny front wings which 
 are useless so far as flight is concerned being modified to 
 serve as covers for the wings and for the abdomen. The 
 hind wings are the organs for flight. Reduction of the front 
 wings is to be noticed in a number of cases and in some 
 species they cover only a small portion of the body. 
 
 The Coleoptera and Diptera so far as wings are concerned 
 are about equally specialized. In the mouth parts the Cole- 
 optera are very much less specialized than the Diptera — they 
 retain the primitive structure. The mandibles are some- 
 times reduced but are functional in the adult stage and 
 sometimes very strongly developed. They are not modified 
 into suctorial organs. 
 
 The metamorphosis is complete and the stages quite 
 distinct. There are the four stages common to insects with 
 complete metamorphosis and in some groups the larvse are 
 further specialized, so that there are two or three different 
 larval forms (hypermetamorphosis) . The beetles have been 
 studied perhaps more than any other group unless it be the 
 Lepidoptera. They are more easily preserved than most 
 insects and often of striking form or conspicuous colors. 
 The beetles probably number at least 100,000 species, and 
 in this country 10,000 or 12,000 species are recognized. 
 A considerable number of these are of economic importance. 
 The group is separable into two quite distinct divisions. 
 (172) 
 
GROUND BEETLES 
 
 173 
 
 the Rhyncophora are the more speciaUzed. The head is 
 drawn out in a snout and the mandibles are much reduced 
 in size. The larval forms are more specialized, usually fitted 
 for living within seeds or parts of plants. 
 
 In the arrangement of families the tiger beetles are usually 
 placed first, but it would seem fully as proper to place Cara- 
 bidcB in this position. 
 
 Tiger Beetles (Cicindelidoe) .—The tiger beetles are found 
 along roadsides, bare ground, or sandy beach. It is not easy 
 to get the larval forms. The larvse are carnivorous and 
 make little burrows in the earth and catch insects that come 
 along at the surface. 
 
 Fig. 122. — Calosoma scrutator. 
 
 Fig. 123. — Lebia grandis, 
 an important enemy of the 
 potato beetle. Enlarged. 
 (Chittenden, Div. Ent., U. S. 
 Dept. Ag.) 
 
 Ground Beetles (Carabidce).— The ground beetles are less 
 specialized. They live usually at the surface of the ground 
 and the larvse are provided with three pairs of normal legs 
 and run about readily and are in fact quite primitive in 
 appearance and habits. They are, as a rule, carnivorous, 
 but a few species attack plants. 
 
 Some of the more important beneficial species are the 
 common ground beetle {Calosoma calidum), a black species 
 with a series of metallic golden spots, abundant over a large 
 part of the United States, and which feeds commonly on 
 
174 COLEOPTERA— BEETLES 
 
 cut worms, caterpillars, etc. The searcher (^alosovia scruta- 
 tor, a })rilliaiit green species with metallic border on elytra 
 and mar<i:in of })r()thorax which, while a general feeder on 
 ground-li\'ing insects, is also credited with climbing trees 
 to feed upon canker worms. The Calosoma sycophanta, an 
 old-world species that is especially useful in keeping the 
 Gij)sy moth in check, has been introduced into INIassachusetts 
 in hopes that it may assist in control of this pest. 
 
 There are several families of aquatic Coleoptera which live 
 almost entirely in water, although at times the adults issue 
 and fly. The carni\'orous water beetles ( DysticidcE) have 
 peculiar circular or oval sucking disks on the front legs, and 
 are distinctly aquatic, the adults appearing out of water, 
 and like the ground beetles, they feed quite exclusively upon 
 other animal life and doubtless occupy a somewhat impor- 
 tant place in the relations of aquatic forms. 
 
 The Hydro philidcE are more distinctly herbivorous and 
 may be considered as water scavengers, feeding upon vege- 
 table debris and serving as important members of the 
 aquatic association. It is a large family, including a great 
 many genera and species, but from their habits are naturally 
 of little economic importance. 
 
 The GyrinidoB or whirligig beetles are quite remarkable 
 for their movement on the surface of water. They dart 
 around with the greatest rapidity, making all sorts of irregu- 
 lar movements but when a group of them are together they 
 form a bewildering array of darting forms. Although 
 dozens or even hundreds of them may be in a group they 
 seldom if ever seem to have a collision among the different 
 individuals in the cluster. A remarkable feature in their 
 structure is the separation of the compound eye at the side 
 of the head so that the upper portion is abo\'e water and 
 the lower portion submerged. They are said to feed mainly 
 upon flies and stranded insects of various kinds that are 
 caught on the surface of the water. One of our common 
 species is the Dineutes americana. 
 
 Family Platypsyllidse. — The PJcdypsyUidw is a small 
 family including a very remarkable parasite of the beaver. 
 
FAMILY COCCINELLID.E 175 
 
 The female is about 2J mm. in length, and ovate in form with 
 very short wing pads so that the abdominal segments are 
 exposed. The eyes and wings are both aborted. 
 
 Family Silphidse. — The Silj^hidce, carrion beetles, are 
 very distinctly scavengers and where there is an accumu- 
 lation of decaying organic matter they doubtless serve a 
 valuable function in disposing of such material that is 
 detrimental. 
 
 Sexton Beetles {Necrophorus). — The sexton beetles are 
 the largest of the family. They bury small mammals such 
 as rats or mice and upon these lay their eggs. The larva 
 then feed upon the decaying flesh. ^ 
 
 The species of Silpha are commonly found about dead 
 fishes or carcasses of dead animals and both the adults and 
 larvae feed upon the rotting material. 
 
 Rove Beetles (StaphylinidoB).— The Staphylinidce are also 
 largely scavengers. The group is a very large one including 
 many hundreds of species. They are characterized par- 
 ticularly by the structure of the wing covers which extend 
 only to the base of the abdomen. The hind wings are 
 folded by means of hinges on the wing margin so that they 
 can be attached under the short wing-covers. The abdomen 
 is left exposed and as the joints are flexible it can be moved 
 about readily and the tip is used in manipulation of the wings 
 preparatory to flight, or when they are folded after flight. 
 
 Several other families related to this division must be 
 passed over. 
 
 Family Coccinellidse. — Lady Bugs. — These are abundant 
 and very important insects, since practically all the members 
 of the family are carnivorous and feed upon insects which 
 for the most part are very destructive. They are especially 
 serviceable in the control of plant lice and scale insects. 
 The adults are short, generally hemispherical or oval, 
 convex above with under side flattened. Usually they are 
 rather conspicuous: some are red with yellowish or black 
 spots, while others are black with red or yellowish spots. 
 
 The larvae are very voracious insects and feed quite ex- 
 clusively upon insects, so that they are considered of special 
 
176 
 
 COLEOPTERA —BEETLES 
 
 service and pains should he taken not to destroy them. They 
 are short, flattened, rather broad, and usually with rather 
 prominent spines or hairs as indicated in the accompanying 
 figures. 
 
 Fig. 124. — A lady bug (Hippodamia convergens) which preys on the 
 Colorado potato beetle. Enlarged. (Chittenden, Div. Ent., U. S. Dept. 
 Ag.) 
 
 Fig. 125. — Spotted lady bug (Megilla inaculata): a, larva; 6, empty 
 pupal skin; c, beetle, with enlarged antenna above. All enlarged. (From 
 Chittenden, Div. Ent., U. S. Dept. Ag.) 
 
 A number of species are abundant and of special service 
 in various parts of the United States. Some of these are 
 figured, and further description will be unnecessary. 
 
FAMILY CUCUJID.^ 
 
 177 
 
 Vedalia. — One species of particular interest is the Vedalia. 
 This was introduced into Cahfornia for the purpose of con- 
 trolHng the cottony-cushion scale and was so efficient in this 
 respect that the scale insect has become of little economic 
 importance. 
 
 Family Cucujidae. — Saw-toothed Beetle. — The family Cucu- 
 jidce includes, with other pests, the saw-toothed beetle 
 (Sylvanus siirinamensis) , probably one of the most frequently 
 noticed pests of stored cereal foods, especially those in 
 packages. It is a little, dark red-brown beetle with the 
 
 Fig. 126. — Adalia bipundata: a, larva; h, mouth parts of same; c, 
 claw of same; r^, pupa; e, ad\ilt; /, antenna of same. All enlarged. (From 
 Marlatt, Div. Ent., U. S. Dept. Ag.) 
 
 edges of the prothorax strongly toothed. It is found in a 
 great variety of food substances, including breakfast foods, 
 yeast cakes, nuts, and dried fruits. 
 
 All stages of the insect may occur in these substances, 
 the larva being a slender, somewhat flattened creature, the 
 pupa being about the shape of the adult. The adult tunnels 
 through cases or migrates from place to place, depositing its 
 eggs adjacent to the materials in which the larvae will grow. 
 There are probably several generations each year, especially 
 in the food materials that are in warm situations. They 
 should not be present in fresh-packed cereals, but owing to 
 12 
 
178 
 
 COLEOPTERA— BEETLES 
 
 tlie fact tlmt tliey become very numerous in mills it is quite 
 probable that eggs may be included in the package and the 
 larvse developed later. 
 
 Family Lyctidse. — The family Lyctidce includes a number 
 of wood-feeding species, for which the powder-post beetle 
 (Lyctvs planicoUis) will serve as a fair example. 
 
 Dermestidse. — The DermestidoB are forms that live on 
 decaying animal matter. Good examples may be found by 
 
 Fig. 127. — The saw-toothed grain beetle: a, adult; b, pupa; c, larva 
 or grub. Greatly enlarged. (After Chittenden, Div. Ent., Bull. 4, n. s., 
 1896, U. S. Dept. Ag.) 
 
 examining dead fish and other decaying organic matter. 
 Some of the species are museum pests, and troublesome in 
 bird collections, and a very particular pest of insect collec- 
 tions. On account of this it is necessary to keep collections 
 in insect-proof boxes or else fumigate with carbon bisulphide. 
 Larder Beetles (Derviestes lardariiis). — The adults appear 
 particularly in early summer and the eggs are deposited on 
 or near materials that furnish food for the larvae. The eggs 
 
FAMILY DERMESTIDM 
 
 179 
 
 require probably only a few days for hatching, long enough 
 when laid on insects, so that it is possible for the insects to 
 be transferred from one box to another and to introduce 
 them into new boxes. In case of hams and bacon, these 
 eggs may be on the hams when they pass from one dealer 
 to another. The larvae grow most rapidly during the sum- 
 mer months and if there are any distinct broods it would 
 be the rapidly developing generations in the summer time. 
 But the broods are not very sharply marked. There may 
 be two or three broods, but the development is irregular 
 enough, so that they are developing at all times of the year. 
 The larvae do the feeding and devour the tissue, and the 
 
 Fig. 128, — A powder-post beetle (Lyctus vlamcollis) : a, larva; b, adult; c, 
 pupa; line to right of adult represents natural length. (Chittenden, Div. 
 Ent., U. S. Dept. Ag.) 
 
 pupation takes place early. The larvae may burrow through 
 paper or wooden cases and then give rise to adults in a 
 comparatively short time. 
 
 Museum Beetle. — A related species — the museum beetle — 
 is more a museum pest and less a pest in other ways. It 
 lives in skins of mounted animals and other dried animal 
 tissue. 
 
 Carpet Beetles. — Closely related is the carpet beetle, which 
 is a pest in fur and woollen goods and seldom if ever known 
 as a pest in museums. It is fond of woollen carpets and 
 furs. These seem to be its particular food supply. It was 
 introduced from Europe and has spread over the entire 
 
180 
 
 COLEOrrEHA— BEETLES 
 
 country but is not very abundant for tlie most part. It 
 is less abundant where rugs are used than where carpets are 
 used. 
 
 Click Beetles {FJatcridcp). — Click beetles are interesting on 
 accoiHit of structure and their habits which are of economic 
 importance. They make a sudden click and throw them- 
 selves up into the air. This is produced by a little s})ur on 
 the prothorax which fits into a little pit in the mesosternum. 
 This is characteristic of the entire family and is not found 
 in any other family. Its purpose is to throw the insect into 
 the air and allow it to turn over. The larva? are called 
 
 Fig. 129.- — Click beetle and wire worm {Melanotus communis): a, 
 beetle. (After Bruner.) 
 
 larva; h, 
 
 wire worms. These are very troublesome pests. INIany of 
 them are primarily grass-root feeders and will be found as 
 larvae in grass lands, the larvse living just below the surface 
 of the soil, and feeding mainly on the roots of the grass. 
 When the land is plowed and planted in corn or some other 
 crop the wire worms attack this other crop, sometimes in 
 a much more noticeable manner than they do the grass. 
 The larvae are not capable of migrating very great distances, 
 and must depend on the vegetation that is present where 
 they are hatched. The length of the larval period is show^n 
 by their presence in a field of corn three years after it has 
 
BUPRESTIDjE 181 
 
 been plowed from grass. Many of the species have never 
 been traced through in detail, but those that have been traced 
 show them to be grass-feeding species, and the eggs are 
 deposited on grass lands. There are some species whose 
 larvae occur in rotten wood and a few have a phosphorescent 
 property. These are not of economic importance. 
 
 Buprestidse.— The Buprestidce have larvae that are wood- 
 boring in habit and on account of their shape — the very 
 broad anterior segment of the body — are called the flat- 
 head borers. Destructive species occur in maple, apple, 
 hickory, and a considerable number of common trees. The 
 best-known is the ilat-headed apple-tree borer {Chrysoho- 
 thris femomta), which affects apple and also maple, and 
 perhaps other trees. The adult is a somewhat flattened and 
 elongated oval beetle with rather shallow metallic pits on 
 the wing covers. They appear in early summer and will be 
 found running about over the bark of the trees where the 
 sun strikes them, and the eggs are deposited on rough 
 spots of the bark and hatch in a short time. The larvae 
 burrow just beneath the bark and burrow out a shallow cavity, 
 limiting themselves to the cambium at least in the earlier 
 part of their lives. The cavity eaten out may be one-half 
 to three-quarters of an inch wide. The head is small but the 
 first' segment of the body is quite large and flat and is per- 
 haps rather naturally taken to be the head by ordinary 
 observers. The remaining segments are slender and nearly 
 cylindrical. It lies in the cavity in a flat position. The 
 burrows never go down into the heart of the tree but they 
 produce dead patches in the growing wood at the surface, 
 and if they are numerous they may form a girdle and cut 
 off the sap. The larvae make their growth two or three feet 
 from the ground on apple trees and occur about the lower 
 branches and a few may girdle the tree. The cycle of the 
 species is completed in a year. The larvae burrow during 
 the summer and autumn, are dormant through the cold 
 weather, and pupate in the spring, the adults appearing in 
 the summer. The species is usually restricted prett}' closely 
 to one kind of plant. 
 
182 COLEOPTERA— BEETLES 
 
 Lampyridse. — The fire-fly family is quite an exceptional 
 one, and is very interesting on account of the brilliant phos- 
 phorescent property. This is most commonly observed 
 during June and early July and represents the time when 
 the adults are most abundant. There are a number of 
 species possessing the phosphorescent organs. The eggs 
 are deposited and the larvse probably develop during that 
 same summer, and the pupa stage is reached and adults issue 
 the following season. They pupate perhaps in fall or else 
 in spring. They are subterranean and are carnivorous and 
 feed upon the larvse of other species. 
 
 Lucanidse {Stag Beetles). — The lucanidse are large forms 
 with very prominent mandibles which in some species develop 
 into antler-like structures. The Lucanus dama larva lives 
 in rotten wood, old stumps, and logs, etc., and only inci- 
 dentally feeds on living wood. The larvse never start on 
 living wood. The grubs are large, white, fleshy creatures 
 with the body curved, almost coiled, and they pupate in the 
 wood in which they are developed and the adults run over 
 the ground in timber lands. The adults are quite common 
 along the beach. They are not adapted for long flight. 
 
 A quite interesting species is the horned Passalus {Passa- 
 liis cornuttis) which lives in wood in almost the same manner 
 as the last species, but the larva is flattened and the adult 
 quite prominently flattened. The wings are considerably 
 aborted and the species probably quite limited in its flight. 
 
 Scarabseidse. — The ScaraboBidoe are characterized quite 
 readily by the structure of the antennae. They have a very 
 specialized form of antennae consisting of a series of small 
 joints and then a broad terminal structure which is made 
 up of three or five leaves folded together like the leaves of a 
 book. These may be separated when the insect is flying. 
 They are presumed to be the organ of the sense of smell. 
 There are many sensory pits, and they give evidence of hav- 
 ing strong olfactory sense, in that they collect at any decay- 
 ing matter. They are not all scavengers, but they all have 
 an acute sense of smell. The tumble bugs and a host of 
 scavenger beetles related to it are included in this family. 
 
SCARAB^IDM 
 
 183 
 
 The Egyptian scarabs belong here. The tumble bugs 
 simply enclose their eggs in little masses of refuse matter. 
 This is to serve as food substance for the larvae, and they 
 shape it in a ball and roll it along until it becomes coated 
 with earth. The balls are finally buried in the earth. The 
 eggs hatch here and the larvse develop and get their sub- 
 sistence from the material in the ball. 
 
 Fig. 130. — Corpris Carolina, under side. Enlarged. (From photo.) 
 
 May Beetles or June Bugs. — Important economic species 
 are the leaf-eating species. These are species of the genus 
 Lachnosterna — Lachnosterna fusca in particular. These are 
 known as May beetles or June bugs. They are distributed 
 all through the country. There are perhaps twenty-five or 
 thirty common species which occur in great abundance 
 about the same time of the year, but these differ in minute 
 characters of genitalia. They were formerly all grouped 
 
184 
 
 COI.Eorr ERA— BEETLES, 
 
 species. Tlioy are lejii'-eating in the adult 
 stage. The adults ap])ear rather early in summer, May or 
 June. They are destructive in the adult stage by cutting 
 ofr the leaves of trees. They do not eat the leaves much 
 l)ut cut them off at the petiole. Sometimes trees are 
 completely stripped. They mate in the e\'ening when they 
 fly in great numbers. The eggs are deposited out of doors 
 and in grass land particularly. The larvae feed on grass 
 roots, and if this remains available they develop there in 
 
 Fig. 131. — The common May heQile {Lachnosterna fused): 1, the pupa; 
 2, the larva or white grub in its ground cell; 3 and Jf., the beetle, side and 
 dorsal views. (After Riley.) 
 
 about three years and when they get fairly near maturity, 
 about the spring of the third year, they cut off the roots of 
 the grass pretty severely, sometimes cutting the turf oft' 
 completely. This causes the same kind of loss as is caused 
 by cut worms, grasshoppers, etc., or more severe because 
 of injury below the crown. At this time they are known as 
 white grubs and are similar in appearance to the larvae of the 
 stag beetles. If the grass is plowed under and the field is 
 planted to some other crop the grubs starve or else attack 
 
SCARAByEID^ 
 
 185 
 
 the other vegetation which sometimes suffers severely. 
 Strawberry beds are quite hkely to suffer. There are no 
 satisfactory' remedies. About the only thing that could be 
 of much use is attention at the time of egg deposition. Appli- 
 cation of kerosene has been reported in some cases as suc- 
 cessful on small areas such as lawns or parts of park land. 
 
 Rose-chafer {Macrodadyhis subspinosiis, Fab.).^ — The rose- 
 chafer is a small, yellowish-brown beetle, about one-third 
 of an inch in length, with very long legs. It occurs in great 
 
 Fig. 132. — Rose-chafer {Macrodactylus subspinosus) : a, female beetle; 
 b, anterior part of male; c, pygidium of male; d, abdomen of male; e, pupa; 
 /, larva. All enlarged. (From Riley, Div. Ent., U. S. Dept. Ag.) 
 
 numbers at the time of the blossoming of the garden rose, 
 and will in a couple of weeks entirely strip the bushes of 
 blossoms, leaves, and fruit. It also attacks the grape, 
 apple, pear, cherry, peach, and other fruit trees, but is 
 especially injurious to the rose and grape. 
 
 The ravages of the rose-chafer are common in eastern 
 United States and Canada. The date of the first appearance 
 of the rose-chafer varies with the season but it is usually 
 as early as the first of June. They begin mating imme- 
 
186 
 
 COLEOPTERA— BEETLES 
 
 diately after emerging from the ground. They continue feed- 
 ing from four to six weeks and are almost constantly paired 
 during this time. The eggs are deposited singly a few inches 
 below the surface of the ground, each female laying from 
 
 
 
 
 ^KL 
 
 
 WBUL-^ V ' -^'^^^l 
 
 ^^^^^ 
 
 
 
 Fig. 133.— Rose-chafer work. (Photo from Ohio Exp. Sta.) 
 
 twenty-four to thirty-six eggs. The larva hatches in about 
 two or three weeks and begins feeding on grass and tender 
 shoots. The larva is mature in the autumn and digs down into 
 the earth where it builds a small earthen case in which it 
 
CERAMBYCIDM 187 
 
 passes the winter, pupating in the early spring and emerging 
 as adult early in June. 
 
 There have as yet been no very successful methods of 
 control discovered. Heavy spraying with arsenate of lead 
 when the beetles appear will kill those feeding on the 
 poisoned leaves, but if very abundant, successive attacks of 
 newly appearing individuals may make this of little avail. 
 
 The Cerambycidse. — The wood-boring beetles show quite 
 a different habit from the subterranean forms. They are 
 called the long-horned borers and have very long antennae 
 with usually eleven joints. In the genus Prionus the number 
 is greater. The length of the antennae is produced by elonga- 
 tion of the joints. In some species the antennae are two or 
 three times the length of the body. They are typically 
 wood-boring, and all except one or two genera are borers 
 in the heart- wood of woody plants. Gradations between 
 leaf-feeding and wood-boring are to be seen in a few species 
 that live in the pith of softer plants, and in a few that are 
 borers in the roots. The extremes are perhaps to be recog- 
 nized in those forms that burrow into the heart-wood of 
 the hickory, maple, etc., and that live in such wood after 
 it has been cut and killed. The larvae are the borers. Some- 
 times larvae are found in furniture. They seem to require 
 almost the minimum of moisture and of air. 
 
 Hickory Borer {Chion cinctns). — ^The hickory borer is 
 another species which attacks particularly dead or recently 
 felled trees. Eggs are laid on the dead timber. The borers 
 will gather in large numbers on cord wood the first two or 
 three years after cutting. They sometimes make the wood 
 of comparatively small value for fuel. It is useless for 
 manufacturing purposes. One remedy is to use the wood 
 rather promptly after cutting, within a year. Cutting in 
 the fall is recommended by woodmen, also stripping bark is 
 said to act as a preventative. They do not work during the 
 cold weather. The adults occur onl}^ in the summer. 
 
 Round-headed Borers {Saperda Candida). — The round- 
 headed borers are among the most common pests of orchards 
 and their life-cycle includes about three years. The adult. 
 
188 
 
 COLEOPTER A— BEETLES 
 
 wliicJi is brown with two conspicuous wliite stripes, appears 
 in early summer, ]May or June, deposits eggs at the lower 
 
 Fig. 134. — Chion cinctus: a, eggs, natural size; b, egg, enlarged; c, 
 larva; d, pupa; e, adult male; /, antennae of female. (After Osborn, 
 in Garden and Forest.) 
 
 part of the trunk, near the ground. The larvae on hatching 
 burrow into the tree and for the first season live near the 
 bark, then they burrow down and pass the winter in the 
 
 Fig. 13.'i. — Work of hickory borer, showing longitudinal and cross- 
 section of stick with burrows. One-half natural size. (After Osborn, in 
 Garden and Forest.) 
 
 lower part of the burrow^ perhaps below the surface of the 
 ground. The next two summers are spent in boring upward 
 
CERAMBYCIDyE 
 
 189 
 
 and inward to the heart of the tree and then boring toward 
 the surface, leaving only a thin layer of bark. Before pupat- 
 ing the larva packs the burrow with chips, then withdraws 
 a little from the surface to pupate. The fully grown larvse, 
 pupa3, and adults may all be found in the spring of the same 
 year. All mature and become ready to deposit eggs about 
 June. The adult has simply to work its way through the 
 thin packing of chips and a little bark to reach the surface. 
 It does no real boring in the wood. Few of the species 
 have the abilitv as adults to cut awav the heart- wood. 
 
 Fig. 136. — Saperda Candida: a, larva, from side; h, from above; c, 
 female beetle; d, pupa. All enlarged one-third. (After Chittenden, Div. 
 Ent., U. S. Dept. Ag.) 
 
 There are two means of control. One is to protect the 
 trunk of the tree by means of applications of alkali washes, 
 paint, etc., to prevent the depositing of eggs. Barriers 
 placed around the trunk are used, such as wire netting, tarred 
 paper, and building paper, or even several thicknesses of 
 newspapers. Where such material is used it is better to 
 remove it later in the season (by September first) to give 
 the bark its normal exposure. Another way is to cut out the 
 larvse in the autumn of the first season; the burrow close 
 
190 COLEOPTERA— BEETLES 
 
 to the bark can be found by means of the chips tliat are 
 forced out and project from the burrow or drop tp the 
 ground and form little piles. The grub can be cut out with 
 a clean sweep of the knife and the wound covered with a 
 little wax, thick paint, or something of the kind to prevent 
 entrance of water and formation of decaying spots. 
 
 Leaf Beetles {Chrysomelidce). — The leaf beetles represent 
 rather more primitive habits and have rather more primi- 
 tive characters than CeramhycidcB, the antennae being short 
 and filiform, but are similar in the character of the tarsi. 
 The larvse of ChrysomelidoB with a few exceptions feed on the 
 leaves of plants in a very exposed manner and the adults 
 feed, so far as they feed at all, on the leaves of different kinds 
 
 Fig. 137. — Colorado potato beetle (Leptinotarsa decemlineata) : a, beetle; 
 h. larva; c, pupa. Enlarged. (Chittenden, Div. Ent., U. S. Dept. Ag.) 
 
 of vegetation. They are sometimes restricted to certain 
 plants and sometimes have a variety of hosts. 
 
 The Colorado potato beetle {Leptinotarsa decemlineata) 
 was at one time a much-dreaded pest but can now be easily 
 controlled. It occurred originally in the Rocky Mountain 
 region, feeding on wild plants related to the potato, but with 
 the introduction of the potato and abundance of food it 
 multiplied rapidly, migrated eastward and soon spread over 
 the entire country. It has two generations each year, adults 
 hibernating in the ground, appearing in early spring and 
 laying eggs on first-appearing potato vines. The larvae 
 which hatch soon feed on the leaves, maturing in a short 
 time, pupating under ground, and a summer generation of 
 
CHRYSOMELIDJE 
 
 191 
 
 beetles appears in midsummer. These lay eggs, and larvae 
 may be very abundant in late summer, pupate in early fall, 
 and give rise to beetles that hibernate. Spraying with 
 arsenical solutions is effective in their control. 
 
 Agriculturally a little group of beetles, the Diabrotica, 
 are very important. They present an exception to the gen- 
 eral habit of the family in that they attack roots under the 
 ground. There are three species of interest. The best- 
 known species is the striped squash beetle ( Diabrotica 
 
 Fig. 13S. — Striped cunumber beetle (Diabrotica Httaia): a, beetle; 6, 
 larva; c, pupa; d, egg; a, h, c, much enlarged; d, more enlarged. (After 
 Chittenden, Div. Ent., .U. S. Dept. Ag.) 
 
 vittata), a pest to squashes and melons, which is an extremely 
 well-known species. It feeds on stems and leaves close to 
 the ground and, as larva, in the young squashes, and per- 
 haps represents the intermediate stage between stem and 
 root-feeding species. 
 
 Diabrotica longicornis, the corn-root worm, is distinctly 
 a root-feeding species. The beetle appears in late summer 
 and autumn and is a rather bright green little beetle with 
 no markings. It is found in late summer on the corn stalks, 
 on the fall flowers, such as asters, sunflowers, goldenrod, 
 
192 
 
 CO LEO I' 1 'ERA —BEE 7 'LES 
 
 etc., and feeds perhaps on the pollen of tliese flowers. In 
 some cases it is quite remote from the corn fields. They 
 deposit eggs in the ground. The eggs remain over winter 
 and hatch the following spring shortly after the corn begins 
 to grow, and the larva commences feeding on the corn roots. 
 While the roots are small they commence at the end and 
 work along the root; after the roots are larger they work 
 into the roots. They cause the ears to be small and when 
 numerous can kill out the entire plant. They get their 
 growth by the middle of July or first of August, pupate, 
 and spend a few days in the pupal stage, and issue as adults 
 
 Fig. 139. — "Western corn-root worm (Diabrotica longicornis) : a, beetle; 
 h, larva or root worm; c, enlarged leg of same; d, pupa — all enlarged; 
 c, more enlarged. (Chittenden, Div. Ent., V . S. Dept. Ag.) 
 
 in autumn. There is a single brood in a year. Rotation of 
 crops serves as an almost absolute means of prevention of 
 injury from this species. It was most troublesome in the 
 corn regions of Illinois where corn was planted year after 
 year on the same ground. 
 
 The other species with this habit is also destructive to 
 corn ( Diabrotica \2-yunctata) . It is known as the Southern 
 corn-root worm. It is also troublesome to some other 
 plants, so that its control is not so easy or certain. 
 
 The elm-leaf beetle, an introduced species which has been 
 a very serious pest in the Atlantic States, has recently 
 
FAMILY BRUCHID^ 
 
 193 
 
 occurred in Ohio. It has worked westward from some 
 infected centre in the east, and is apparently spreading over- 
 the country in general. 
 
 The cucumber flea beetle and grape-vine flea beetle also 
 come in this group. 
 
 Family Bruchidse. — The family Bnichidcp in some respects 
 approaches very near the snout beetles. This includes the 
 pea and bean weevil and the species are essentially seed- 
 
 FiG. 140. — Southern corn-root worm (Diahrotica 12-punctata) : a, beetle; 
 b, egg; c, larva; d, anal segment of larva; e, work of larva at base of corn 
 stalk; /, pupa. All much enlarged except e, which is reduced. (After 
 Riley, except/, after Chittenden, Div. Ent., U. S. Dept. Ag.) 
 
 eating forms. In case of the pea weevil the eggs are laid 
 out of doors on growing pea pods and they burrow into the 
 pod and get into the growing peas, usually one to each pea. 
 They grow with the growing pea and remain in the pea to 
 pupate and then later the adults are found in stored peas 
 in winter and spring. Immense numbers of these larvae 
 are destroyed by the eaters of green peas but the species 
 holds its own. It does not become noticeable except in 
 stored peas. The larvse at the time of green peas are small 
 13 
 
194 
 
 COLEOPTERA— BEETLES 
 
 and soft, probably of a good flavor like the pea, and do not 
 attract any attention at all. The way of preventing its 
 occurrence is to pick out the infested peas and treat them 
 before planting. Soaking in cold water for several hours 
 
 Fig. 141. — Elm-leaf beetle (Galerucella lufeola): a, e, eggs; 6, g, larvae; 
 c, k, adults; /, sculpture of egg; /i, side view of segment of larva; i, dorsal 
 view of same; j, pupa; I, portion of elytron of adult; a, b, c, natural size; 
 0, j, k, somewhat enlarged; e, h, i, I, much enlarged; /, highly magnified. 
 (From Riley, Div. Ent., U. S. Dept. Ag.) 
 
 kills the adults and prevents egg deposition. Warm water 
 may be used and will hasten the death of the larva but it 
 must not be so hot as to kill the germ. Buggy peas will 
 germinate usually just as readily as the sound ones but 
 have less material to grow on. Peas that are kept in bins 
 
RHYNCOPHORA 
 
 195 
 
 or sacks where the adult cannot get out can do no harm to 
 the new fields. Fumigation of the seed is one method of 
 destroying the beetles. In some places it is required by law. 
 The Rhyncophora or snout beetles are distinguished by 
 the elongate head drawn out into a narrow and sometimes 
 
 Fig. 142. — The clover-leaf weevil (Phytonomus punctatus): a, egg; 
 b, b, b, b, larvae feeding; c, recently hatched larva; d, head of same from 
 beneath; e, jaw of same; /, cocoon; (7, meshes of cocoon; /i, pupa; i, beetle; 
 j, same in outline; k, same dorsal view; I, tarsus of beetle; tn, antenna of 
 same; b, f, i, natural size; others more or less enlarged. (From Riley, 
 Div. Ent., U. S. Dept. Ag.) 
 
 very long "snout" ai the end of which the minute mouth 
 parts are attached. The larvse are commonly found as 
 grubs in seeds, nuts, etc., but the clover-leaf w^eevil and the 
 alfalfa weevil feed upon the leaves and stems of clover and 
 alfalfa. 
 
196 
 
 COLEOPTERA— BEETLES 
 
 Plum Curculio {ConotrachcJvs iiennyhar, Horbst.). — This 
 pest is still one of the main difficulties in the way of raising 
 good crops of plums, but it may be considered at least pos- 
 sible, by proper care, to secure good crops of perfect fruit. 
 The beetles hibernate and appear on the trees shortly after 
 bloom, feeding to some extent on the leaves and young 
 fruit, and then laying their eggs in the young plums, the 
 punctures indicating point of deposition being marked with 
 a crescent-shaped cut. The larvae burrow through the pulp 
 
 Fig. 143. — The larger chestnut weevil (Balaninus proboscideus) : a, 
 female beetle; b, same in outline from side; c, head, rostrum, and antennae 
 of male. Three times natural size. (Chittenden, Div. Ent., U. S. Dept. 
 Ag.) 
 
 of the plum, not entering the stone. The infested fruit 
 ripens prematurely and falls from the tree, and the larvse 
 for the most part leave the plums and pupate under ground. 
 The adult beetles appear in late summer or early autumn 
 and live over till the following spring. 
 
 The beetles drop readily when disturbed, and the well- 
 known plan of jarring trees daily during the time of egg 
 deposition in the morning and gathering the beetles on can- 
 vas spread under the trees is a valuable means of preventing 
 
RHYNCOPHORA 
 
 197 
 
 their injuries. Spraying with an arsenical solution has 
 been found to be useful, and if the plum trees are thoroughly 
 sprayed once soon after the bloom has fallen and again ten 
 
 Fig. 144. — Larger chestnut weevil (Balaninus proboscideus) : a, larva; 
 b, c, female pupa; d, eggs. All enlarged. (Chittenden, Div. Ent., U. S. 
 Dept. Ag.) 
 
 Fig. 145 Fig. 146 
 
 Fig. 145. — Balaninus proboscideus: head of larva, much enlarged. (Chit- 
 tenden, Div. Ent., U. S. Dept. Ag.) 
 
 Fig. 146. — Pecan weevil (Balaninus caryce): a, female, dorsal view 
 6, same, lateral view, in outline; c, head with rostrum and antenna of male. 
 About two and one-half times size. (Chittenden, Div. Ent., U. S. Dept. 
 Ag.) 
 
 days later, it will greatly help in securing perfect fruit. 
 Some experiments have shown extremely valuable results 
 in this direction. 
 
198 
 
 COLEOPTERA— BEETLES 
 
 The nut weevils have enormously elongated snouts. 
 They infest chestnuts, pecans, acorns, hazel-nuts, etc. 
 
 Fig. 147. — Hazel-nut weevil {Balaninus obtusus) : a, adult female, dorsal 
 view; 6, head from side; c. head of male from side. Enlarged. (Chittenden, 
 Div. Ent., U. S. Dept. Ag.) 
 
 Fig. 148. — Boll weevil (Anthonomus grandis): a, adult beetle; h, pupa; 
 c, larva. All enlarged. (From Howard, Div. Ent., U. S. Dept. Ag.) 
 
 Cotton-boll Weevil. — In the Southern States we have a 
 most striking case of introduction and dispersal in the 
 cotton-boll weevil, which came into southern Texas from 
 Mexico about the year 1890 and has been making steady 
 
-30 
 
 o 
 
 C 
 
200 
 
 COLEOPTERA— BEETLES 
 
 progress throiigliout tlie cotton-growing States. It is a small 
 beetle somewhat like the clover wee\'il but restricted to the 
 cotton plant for its food and for the early stages is restricted 
 to the bolls of cotton for its particular food. This means 
 that it can develop only in places where cotton grows and 
 at such time as the cotton bolls are in process of develop- 
 ment. This species has practically revolutionized the agri- 
 cultural conditions of the Southern States in which it has 
 spread, and it is unnecessary to say that it must have had 
 
 Fig. 150. — White-pine weevil (Pissodes strobi): a, adult, smaller figure 
 natural size; b, larva, line at left natural length; c, pupa, small figure of 
 adult showing natural size. (Hopkins, Div. Ent., U. S. Dept. Ag.) 
 
 a very pronounced influence upon the other kinds of insects 
 or animals that occur in that region. 
 
 The map illustrates its progress from year to year and it 
 is a matter of considerable interest and significance that 
 the northern border of its distribution has remained inside 
 the possible area of cotton growth. It may also be noticed 
 that this line agrees remarkably for the northern distribu- 
 tion of the cattle tick and other insects which are of tropical 
 derivation. 
 
RHYNCOPHORA 
 
 201 
 
 Fig. 151 
 
 Fig. 152 
 
 Fig. 153 
 
 Fig. 154 
 
 Fig. 151. — Hylastinus obscurus: adult insect — natural size at right. 
 (Webster, Div. Ent., U. S. Dept. Ag.) 
 
 Fig 152. — Hylastinus obscurus: larva or grub — much enlarged. (After 
 Webster, Div. Ent., U. S. Dept. Ag.) 
 
 Fig. 153. — Hylastinus obscurus: pupa — much enlarged. (After Webster.) 
 
 Fig. 154. — Clover root, showing work of Hylastinus obscurus. Slightly 
 enlarged. (After Webster, Div. Ent., U. S. Dept. Ag.) 
 
202 
 
 COLEOPTERA— BEETLES 
 
 Fig. 155. — Scolytus rugulosus- o, beetle; b, same, in profile; c, pupa; 
 d, larva. All magnified about ten times, (Bur. Ent., U. S. Dept. Ag.) 
 
 Fig. 156. — Scolytus rugulosus. Section of injured tree. (Photo from 
 Ohio Exp. Sta.) 
 
RHYNCOPHORA 
 
 203 
 
 The insect hibernates as an adult and may be carried by 
 shipments of cotton seed or other objects. The eggs are 
 laid on cotton bolls in early summer and the larvse feed 
 within the bolls, ruining the fibers that would form the 
 crop. 
 
 Fig 157.— Dendroctonus valens: adult. (A. D. Hopkins, Bur. Ent., 
 U. S. Dept. Ag.) 
 
 Diversified farming, the clearing up and burning of old 
 cotton plants in the fall and early planting are some of the 
 measures used in efforts to control the species. 
 
 The white-pine weevil is a destructive species m the pnie 
 forests of the Northern States and Canada and occurs south- 
 ward along the Allegheny range to North Carolma. 
 
 Scolytidse or Engraver Beetles and Bark Beetles.— ihese 
 are interesting because of their forming characteristic mark- 
 
204 
 
 COLEOPTERA— BEETLES 
 
 ings between tlie bark and the wood. They are a great 
 economic pest in forests. The pine forests of Virginia, 
 Georgia, etc., and the Black Hills have been greatly injured. 
 
 Fig. 158. — Dendroctonus valens: work in bark at base of stump: a. en- 
 trance and pitch tube; b, egg gallery; c, boring dust and resin; d, pupal 
 cell; «", pupa: /, larvae at work feeding on inner living bark; (7, exit burrows; 
 h, resulting old scar or basal wound, often referred to as basal fire wound; 
 i, inner bark with outer corky bark removed. (A. D. Hopkins, Bur. Ent.. 
 U. S. Dept. Ag.) 
 
RHYNCOPHORA 205 
 
 One of the destructive species {Hylastinvs obscurus) is a 
 borer in the roots of clover and occasions much injur}^ to this 
 crop. 
 
 Fruit-tree Bark Beetle (Scolytus rugulosus). — The fruit-tree 
 bark beetle is a common pest of orchard trees and the cause 
 of much injury. Its work becomes apparent in numerous 
 small round holes in the bark. Shot-hole borer is one name 
 for the species, based on this feature. 
 
 The species of Dendroctonus are mainly destructive to 
 forest trees, and are responsible for extensive inroads on 
 our forest resources. 
 
CHAPTER VIII. 
 
 LEPIDOPTERA. 
 
 The Lepidoptera form one of the largest orders of insects 
 including a great number of subdivisions and including 
 some of the most brilliant forms and some of the extremes in 
 size — moths, butterflies, etc. They are separated from all 
 other insects by the mouth structure, it being adapted for 
 lapping up nectar of flowers and this structure being devel- 
 oped largely from the maxillae, the parts being elongated 
 
 ,., MESOTHOfiAX\ 
 
 ABDOM£N MerATHOMX \ \ 
 
 TnoOKtCLEG' 
 
 Fig. 159. — Tomato worm (larva of Phleqethontius 5-maculata), showing 
 structure of lepidopterous larvae. (Drawn by J. I. Hambleton.) 
 
 and extended for some length when in use and when not 
 in use folded up like a watch spring. Some forms have 
 remnants of rudimentary mandibles but in most cases these 
 cannot be found. When they occur the mouth parts seem to 
 be in their general structure related to the Trichoptera.' 
 The larvae are all mandibulate. Another distinctive character 
 is the complete covering of body and wings with minute 
 scales. 
 
 The Lepidoptera show quite extreme condition in meta- 
 morphosis. The larvae are known as caterpillars. They 
 ( 206 ) 
 
BAG-WORM MOTHS 
 
 207 
 
 usually have a series of prolegs or false legs developed on 
 the abdominal segments. The more common number is 
 ten, four pairs located on the central abdominal segments 
 and one terminal pair. These are not homologous with the 
 segmentally jointed appendages of insects generally. They 
 stand out prominently and are fitted commonly with rows 
 of small hooks or teeth at the margin. The larvse are elon- 
 gate and generally cylindrical and are followed by a pupa 
 stage strikingly different from the larval stage and fre- 
 
 FiG. IGO. — Bag worm (Thyridopteryx ephemerceformis) : a, full-grown 
 larva; h, head of same; c, male pupa; d, female pupa; e, adult female; 
 /, adult male. All enlarged. (From Howard, Div. Ent., U. S. Dept. Ag.) 
 
 quently enclosed in a cocoon. This is a quiescent stage. 
 The adult on issuing splits the pupal case along the dorsal 
 portion and crowds its way out. 
 
 Bag-worm Moths. — Among the lower forms are the bag- 
 worm moths. These are forms in which the larvae construct 
 a case or bag of bits of leaves or twigs with which to protect 
 themselves. Almost parallel with the habit of the caddice 
 flies. One of the most common is the evergreen bag worm 
 {Thyridopteryx ephemercEformis) . Its favorite fqod plants 
 are conifera, red cedar, and arbor vitae. It occurs com- 
 
208 
 
 LEPIDOPTERA 
 
 monly over a large ])()rti()n of eastern United States. The 
 bags which are formed by this insect are found abundantly 
 in autumn and mnter and early spring attached to the 
 trees upon which they have developed. They may crawl 
 some little distance from the trees and attach themselves to 
 some other object. Each bag is made up of numerous bits 
 of leaf and twig, making a regular structure. These bags 
 in late summer and autumn furnish protection for develop- 
 
 FiG. 161. — Bag worm (a, b, c) at successive stages of growth: c, male 
 bag; d, female bag. Natural size. (From Howard, Div. Ent., U. S. Dept. 
 Ag.) 
 
 ment of the adult. The females remain within the bag. 
 They are wingless and grub-like with very large bodies. 
 The males issue from the chrysalis and fly about with well- 
 developed wings. After fertilization the females deposit 
 eggs within the bag, filling the cavity of the bag with a mass 
 of eggs. This forms the protective covering for the egg 
 mass during the winter. The eggs hatch in the following 
 season and the larvae begin feeding upon the foliage of the 
 tree and begin the construction of a case or bag almost as 
 
BAG-WORM MOTHS 
 
 209 
 
 Fig. 162. — Bag worm {Thi,ridopieri]x ephemerceformis) cases from 
 cedar tree. 
 14 
 
210 LEPIDOPTERA 
 
 soon as they begin to feed. The bag is made of silk mixed 
 with the bits of leaf, etc., and attached to the twig by silken 
 threads. The metamorphosis to the pupal stage occurs 
 within the case. There is a marked difference in the size, 
 etc., of the males and females in the case. They are a 
 source of injury to evergreen trees, stripping the foliage. 
 They are a little difficult to contend with. Applications 
 of poisonous arsenical solutions to the foliage where they 
 are feeding will kill them. The cocoons may be gathered 
 and destroyed. The migration from tree to tree is limited 
 by the migration of the larvse, as the females remain in the 
 bag and do not travel about. The migrations of the cater- 
 pillars are limited to rather short distances. This is the best- 
 known species of the family. 
 
 Family Cossidse.^The family Cossidce is another group 
 presenting adaptations to special food and includes the 
 carpenter moths — characterizied by the wood-boring habit 
 of the larvae. This is a decided departure from the leaf-feed- 
 ing habit. The leaf-feeding habit is the most primitive 
 condition. They burrow into the heart-wood of various 
 trees. 
 
 Locust-tree Borer {Prionoxystvs robinice). — The locust-tree 
 borer is the most conspicuous. It occurs in other trees 
 besides the locust. The moths are strong-bodied and 
 resemble the hawk moths in the shape of the body and in the 
 narrow form of the wings. The adults appear in June and 
 July and deposit their eggs upon various trees and the larvae 
 on hatching begin burrowing into the tree, living at first 
 in the cambium and then burrowing deeper into the woody 
 tissue. The larvae are supposed to require three years for 
 their growth. The larva is whitish and almost naked with 
 only a few scanty, minute hairs and looks more like the 
 grub of a beetle than like a caterpillar of a moth. It forms 
 a rather large tunnel, the burrow when the larva gets full 
 size being about one-half inch. These burrows frequently 
 permit the entrance of moisture and so start decay and in 
 many cases cause some distortion; they cause trees to break 
 easily. Before changing to the pupal stage they bore out to 
 
FAMILY PYRALID^ 211 
 
 the bark, leaving only a thin layer that has to be pushed off 
 by the pupa before issuing as a moth. 
 
 In another family, PyralidoB, there is one species, the 
 clover-hay worm {Pyralis costalis), which is very destructive. 
 They injure the stored crop of clover. The moths of this 
 species appear in summer, perhaps most abundantly about 
 midsummer. Eggs are deposited largely in the newly stored 
 hay and the larvse feed upon this hay. Perhaps the majority 
 continue their larval life through the winter— the hay 
 becomes matted and filled with the silken webs they spin 
 and with the black gunpowder-like excrement they discharge. 
 
 Fig. 163. — Indian-meal moth {Plodia inter pundella) : a, adult; b, pupa; 
 c and/, larva; d, head; e, first abdominal segment of larva. All enlarged. 
 (After Chittenden, Div. Ent., Bui. 4, n.s., 1896, U. S. Dept. Ag.) 
 
 The hay, while not all consumed, thus becomes unfit for stock 
 food. They get their growth in the hay and change to 
 chrysalids and the adults issue and fly about in hay mows 
 and about hay stacks. 
 
 Closely related is a species known as Pyralis farinalis, 
 which feeds upon stored grain and also upon clover hay. 
 The life-cycle is about the same as of the other species. 
 
 Indian-meal Moth (Plodia interimnctella) . — This is another 
 common pest of food substances. It occurs in somewhat 
 the same materials as the saw-toothed beetle. It is quite 
 different, however, the adult being a small moth somewhat 
 similar to the clothes moth in appearance, although larger. 
 
212 
 
 LEPIDOPTERA 
 
 The eggs are laid in tlie ^'arious food substances, breakfast 
 food, seeds, dried fruits, etc., and the larva which is a small, 
 slender caterpillar feeds in this material and usually spins a 
 web as it works so that the food is made quite undesirable. 
 There are usually two broods each year in the latitude of 
 Ohio, but with warmth, the number of generations may be 
 increased to four or five. As with the preceding species, it 
 is possible to sift out the insects from the flour or meal but 
 if infested to any extent their presence is undesirable and 
 infested packages are best returned to the grocer to exliange 
 for fresh material. The prevention of their entrance into 
 the packages of breakfast foods, etc., should be attended 
 to at the mills or packing houses. 
 
 Fig. 164. — Mediterranean flour moth {Ephestia kuehniella): a, moth; 
 b, the same from side, resting; c, larva; d, pupa; e, abdominal segments 
 of larva; a and d, enlarged; e, more enlarged. (After Chittenden, Div. 
 Ent., Circ. 112, U. S. Dept. Ag.) 
 
 The direct treatment of these insects in stored products 
 where fumigation is possible is in store rooms, but cannot be 
 done as advantageously as in the mills or warehouses or 
 where the cereals are prepared. 
 
 The Mediterranean Flour Moth {EpJwstia kuehniella). — 
 This is a destructive insect, occurring in stored wheat and 
 other grains, and particularly in mills and warehouses, and 
 has now been distributed over all parts of the world where 
 grains and their products are stored. It is one of the most 
 serious pests in the large flour mills of the northern United 
 States, in some cases clogging and stopping the machinery 
 
BEE MOTH 213 
 
 and causing a considerable loss in the flour, meal, or other 
 products. Its life-cycle is fairly continuous where buildings 
 are warm enough to permit its growth. 
 
 The principal methods of control are by means of heat 
 and fumigation. Where a heating system is present, and it 
 is possible to raise the temperature of the building to 125°, 
 this is a most eft'ective plan and requires but a short suspen- 
 sion of the operations of the mill. Where this is not avail- 
 able the use of hydrocyanic gas or bisulphide fumigation is 
 necessary, although frequent cleaning of the building and 
 the careful disposition of insects which are found in the 
 accumulated dust in different parts of the building will serve 
 to keep them in check. 
 
 Bee Moth {GaUeria melloneUa). — The bee moth gets its 
 name from the fact that it lives in the hives of honey bees. 
 It is confined closely to this habit and all stages will be 
 found in and around the hives. The adults are found 
 during the summer months particularly and are com- 
 monly hidden under and around the hives, and if disturbed 
 tend to slip away, crawling into corners or making a 
 short flight to some safe place, almost as slippery as cock- 
 roaches. They gain entrance to the hives by slipping in at 
 the entrance, especially if the entrance is not well guarded, 
 they deposit eggs upon the comb doubtless in some corner 
 where the bees are not numerous. The larvse feed upon the 
 wax and make long burrows around through the combs. 
 According to Comstock, the larva feeds only at night and 
 hides in its burrow during the day. They pupate generally 
 within the hive and upon the tops of the frames or in 
 the corners, and in some cases probably creep outside and 
 get underneath the hive. They spin quite a tough silken 
 cocoon within which they pupate. This stage gives rise 
 later to the moth. There are at least two generations 
 during the season. The first measure in the way of pre- 
 vention is to keep the colonies in good condition and a part 
 of the treatment may consist in looking over colonies and 
 catching and killing any moths, larvse, or pupae that may be 
 observed. 
 
214 LEPIDOPTERA 
 
 Close-wings (CramhicJcr). — The close-winfi^s are named 
 from the i)()sitic)ii of the wings, which are folded down very 
 closely at the sides of the body and in many cases they 
 fit so close to the stem on which they rest that the moth 
 is completely hidden. Many of them are light yellowish 
 and straw-colored which blends quite well with the color 
 of the straw or grass on which they rest. The genus 
 Crambus includes fifty or sixty species, and most of them are 
 grass-feeding species that are to be considered as distinct 
 pests in pastures and meadows, though they only now and 
 then multiply in such numbers as to attract uni\ersal atten- 
 tion. These different species present different life histories 
 and these must be known in detail in order to treat them 
 intelligently. The most abundant species in the Mississippi 
 valley has the following life-cycle. The sod worm occurs in 
 the adult stage about the latter part of May or the first 
 of June and sometimes in very great abundance. They are 
 attracted by light. They deposit eggs at the times of flights 
 and normally deposit these over grass lands, and the eggs 
 are evidently scattered very generally and are extruded 
 singly, evidently with some force. They drop into the grass 
 and on the surface of the ground, and the larvae when hatched 
 feed at or near the surface or burrow a little below the 
 surface of the ground and form a silk-lined tube in which 
 they live and are protected mostly during the daytime, 
 coming to the surface at night to feed upon the fresh leaves. 
 Injthis way they cut grass off very near the surface of the 
 ground'and it falls down and dries up, and is lost for hay and 
 pasturage. The plants are not killed outright. The effect 
 is similar to that of close pasturing of cows or sheep. If 
 the insects eat down into the ground the grass may be 
 killed. They attain their growth in the course of about four 
 or five weeks and pupate in August and the second genera- 
 tion of moths appears during the middle or latter part of 
 August. These may occur in large numbers if the season 
 is favorable. These deposit eggs and the larva? from these 
 begin feeding in autumn and become partially grown but 
 do not mature, remaining in the larval stage over winter. 
 
FAMILY TORTRICIDjE 215 
 
 In the following spring they finish their growth, pupating 
 and issuing as moths in the latter part of May or early part 
 of June. If the grass land is plowed and another crop put 
 on it, especially corn, the crop may suffer very severely. 
 The remedy is to plow the ground early enough in autumn 
 to prevent egg deposition. If plowed in the spring, it should 
 be plowed early. They are attracted very generally to light 
 and trap-lights in fields ought to be very useful. In Iowa, 
 where ground squirrels (13-striped squirrels) are common, it 
 was noticed that the pupae of these sod worms are eaten by 
 the squirrels. They are also parasitized, and this would 
 perhaps help to keep them reduced in numbers. 
 
 A species with a remarkably different food habit lives on 
 the maple scale (scale insects) Coccid-eating. 
 
 Family Tortricidse. — This family includes the leaf-rollers 
 and bud moths. These are characterized by a broad form of 
 the wing and are distinctly opposed to the slender, narrow 
 wings of the Crambus. The costa is very strongly curved. 
 The mouth parts are not Very conspicuous; head small. The 
 larvse are mainly leaf-rollers and inhabitants of the buds 
 of different kinds of plants. These forms have several 
 injurious species. Cacaesia roseana is quite common and 
 troublesome to florists and rose growers. The insects 
 appear very early in the season. The larvse begin to work 
 soon after the leaves have begun to unfold. The leaves will 
 be tied together and the larvae w^ork within this protection 
 and eat away the tissues of the leaf. In some cases they 
 burrow into the opening buds and destroy the blossoms. 
 They attain their growth rather rapidly and form a chrys- 
 alis often in the leaves they have tied together and from 
 this the moth issues. 
 
 Codling Moth. — The worst pest in the group is the codling 
 moth (Carpocapsa pomonella). This causes enormous 
 losses to the orchard industry; millions of dollars being 
 lost each year. Its life history is well known and can be 
 found in almost any work on orchard insects, but stated 
 briefly, consists in a spring brood of insects appearing and 
 laying eggs shortly after apple bloom, a first brood of larvae 
 
216 
 
 LKPJDOPTERA 
 
 is found in early summer, pupation in early July, second 
 brood mates about Au<^ust first, and second brood larva' 
 
 
 
 ^^Hs « jJ^;- Jtf€'' *''^H 
 
 wSm 
 
 
 Wwk 
 
 1 
 
 Fig. 165. — Codling moth {Carpocapsa pomonella) : larvae in cocoons upon 
 bark of apple tree. (Photo by Ohio Exp. Sta.) 
 
 Fio. 166.— Spraying for Codling moth (Carpocapsa pomonella). 
 (Photo by Ohio Exp. Sta.) 
 
FAMILY TORTRICIDM 217 
 
 in fall and early winter. The essential basis for treatment 
 lies in the time and place of egg deposition. The egg is 
 deposited in the calyx of the fruit and the larva burrows 
 into the fruit. 
 
 The whole secret of destroying the species is to have the 
 poison applied placed so that it will get into this particular 
 part of the apple and be there when the larva takes its first 
 meal. Proper application of arsenical solution w^ill prevent 
 95 to 98 per cent, of the injury. Application should be 
 made very soon after the bloom falls while the fruit is still 
 
 Fig. 167. — Codling moth (Carpocapsa pomonella) : young apples in 
 condition for spraying. (Photo by Ohio Exp. Sta.) 
 
 open at the calyx end. There are two broods in a season, 
 The larvse seen in the apples in the winter are the ones from 
 the second brood. They escape from the apples when 
 stored and secrete themselves about the bins and change to 
 pupae, and the moths are ready to issue early in the spring. 
 The insects may be captured as pupse at the end of the first 
 brood so as to prevent the issuing of the midsummer moths. 
 This may be done by means of bands around the trees 
 under which the larvae will crawl to pupate. These bands 
 may be examined every few days and the pupa^ crushed. 
 
218 
 
 LEPIDOPTERA 
 
 The process is somewhat slower and less effective than spray- 
 ing and is now seldom used. 
 
 Fig. 168. — Codling moth {Carpocapsa pomonella): apples too late for 
 spraying. (Photo by Ohio Exp. Sta.) 
 
 A closely related insect, Carpocapsa saltitans, is the basis 
 for the popular phenomenon known as jumping beans, 
 
FAMILY TORTRICID^ 219 
 
 occurring in beans and some other seeds and causing these 
 seeds to jump about in a very pecuhar manner. This is 
 caused simply by the jerking movements of the body of the 
 caterpillar within the seed. 
 
 Clover-seed Caterpillar {GrapJiolitha inter stinctana, Clem.). 
 — The clover-seed caterpillar is often a serious pest to the 
 clover seed. Its work, however, is not confined to the seed, 
 but extends to the leaves, stems, or crown, so that on the 
 whole its capacity for mischief is very great. 
 
 Fig. 169. — Codling moth {Carpocapsa pomonella) : egg. 
 
 The moths are very small and may be generally described 
 as dark brown or nearly black in color. The wing expanse 
 is from 0.31 to 0.36 of an inch. The majority are marked 
 by two small parallel, excurved, short, silvery lines at the 
 middle of the hinder border of each forewing so that when 
 the wings are closed the lines form a double crescent over 
 the back. (See Fig. 167, c and d). Some, however, are found 
 to have all traces of the crescents obliterated. Eight white 
 silky lines are disposed along the front border of each of the 
 forewings, which in common with the hindwings are deli- 
 cately fringed. The wings beneath are shining and silky and 
 have a greenish tinge in certain lights. 
 
220 LEPIDOPTERA 
 
 The larva (Fi**-. 17(),(^/) is a small greenish-white caterpillar 
 with a (lark brown head, and is al)()ut ().2r) to 0..'^ of an inch 
 long when full grown. Many of them become tinged with 
 red toward the hinder extremity as they approach the time 
 of pupating. 
 
 The delicate white silken cocoons are spun in the liead 
 among tlie dried florets, grass, and bits of eroded but im- 
 devoured flowers, so covering them with brown as to make 
 them difficult of detection. The pupae work their way 
 entirely out of their cocoons and drop to the ground before 
 bursting their pupal cases, which may be found in abundance 
 on the ground from which a brood has just issued. 
 
 Fig. 170. — Grapholitha inter stinctana: a, larva; h, pupa; c, adult; 
 all enlarged; d, adult — natural size. (After Osborn.) 
 
 The remedies for the species are summed up as follows: 
 
 1. Rotation of crops, not keeping clover on the same 
 ground over three years, and only two if the field becomes 
 badly infested. 
 
 2. That the seed for a new crop be planted on land as 
 remote as possible from old clover fields. 
 
 3. That infested fields from which seed is desired the 
 following year be pastured in the fall to take up all late 
 growths and leave the field free from vegetation, and that 
 
FAMILY TINEIDM 
 
 221 
 
 no manure be applied at the time to furnish places for the 
 larvae to hibernate. 
 
 4. That clover infested during the spring be cut as early 
 as practicable, while the larvae are in the heads, handled as 
 carefully as possible to prevent shaking larvae from the 
 heads and stored in stacks or barns, the larvae being found 
 to perish under such treatment. 
 
 5. When ready to change from clover to another crop 
 plow under some time in October, November, or in early 
 spring burying the larvae as deeply as possible, and roll or 
 harrow to pack the surface. 
 
 Several pjarasites have been reared which will assist in 
 reducing numbers under ordinary conditions. 
 
 Fig. 171. 
 
 -Tinea pellionella: adult; larva; larva in case — enlarged. 
 (From Riley, Div. Ent., U. S. Dept. Ag.) 
 
 Family Tineidse. — The family Tineidce includes very 
 minute moths which have slender wings and usually with 
 the wings very broadly fringed, and is a specialization or 
 modification from the typical broader wings. They are 
 very delicate, mostly very minute and the more abundant 
 outdoor forms are leaf-miners, the larvae living between the 
 epidermal layers of the leaf and feeding upon the pulp of 
 the leaf. Some form galls. The tough part of the leaf is 
 protective at least to a degree. Some also construct cigar- 
 shaped cases and are known as case-bearers. The best- 
 
222 
 
 LEPIDOPTERA 
 
 known species arc tlic clothes moths, and they have quite a 
 speciahzed food habit, being Hmited to dry woolen fabrics 
 or furs. There are three common species, one the case- 
 bearing clothes moth, one a naked species, and one the 
 carpet moth which constructs a sort of burrow within the 
 goods. The life histories are similar, adults appearing in 
 spring or summer and the larvae feeding in the carpets 
 clothing or furs, especially during the summer months. 
 Naphthaline or "moth balls" are a good repellent, cold 
 storage and storage in moth -tight paper cases are helpful. 
 
 Fig. 172. — Tineola biselliella: moth, larva, cocoon, and empty pupa 
 skin — enlarged. (From Riley, Div. Ent., U. S. Dept. Ag.) 
 
 Sesiidae. — These have a rather unusual condition for the 
 Lepidoptera. In many the scales are wanting and the wings 
 look glassy — like wasps' wings. Scales will usually be found 
 on the veins of wings and on the body and legs, those on 
 the legs -being quite large. They fly in daylight rather 
 than at night and there are a number of distinctly economic 
 species. The larvse are borers and live in the wood of trees 
 and sometimes of annuals. The squash-vine borer is often 
 very destructive to squashes, melons, and pumpkins. 
 
 One of the most common and destructi\'e is the peach-tree 
 borer {Sa7ininoidea cxitiosa). This causes serious damage to 
 peach orchards in the Eastern Central States and southward. 
 The adults vary a great deal in the two sexes. The females 
 are larger and a darker steel-blue with a broad orange-yellow 
 
SESIIDJE 
 
 223 
 
 band about the middle of the abdomen. The males are 
 banded dark and yellow with wings more glassy and body 
 more slender and considerably smaller. They appear in the 
 
 Fig. 173. — Squash- vine borer (Melittia satyrinifonnis) : a, male moth; 
 h, female, with wings folded at rest; c, eggs shown on bit of squash stem; 
 d, full-grown larva, in situ in vine; e, pupa; /, pupal cell. All one-third 
 larger than natural size. (From Chittenden, Div. Ent., U. S. Dept. Ag.) 
 
 Fig. 174. — Sanninoidea exitiosa: 
 full-grown larva; d, female pupa; 
 extruded from cocoon. 
 Dept. Ag.) 
 
 a, adult female; h, adult male; c, 
 
 e, male pupa; /, pupa skin partially 
 
 All natural size. (After Marlatt, Div. Ent., U. S. 
 
 adult stage in midsummer, largely in late July or August, 
 and deposit eggs near the ground around the trunks of 
 peach trees and also plum, cherry, and other stone fruits. 
 
224 LEPIDOPTERA 
 
 Tlie eggs are deposited in crevices or broken places on the 
 bark. The great majority are within six or seven inches 
 of the ground. The larvae soon hatch and bore into the bark 
 and into the soft sap wood. They live close to the bark for 
 a good share of the time. In some cases they are almost 
 exposed. They do not seem to have developed the habit 
 of boring so deeply as some others. During the autujnn 
 they continue this boring, growing somewhat, and hibernat- 
 ing in the larval stage. They go as deep as possible in the 
 winter. In the spring they continue feeding and extend 
 the l)urrows and complete their larval growth in late spring, 
 mostly during May. They pupate within the burrows and 
 are usually so close to the surface that the pupae have no 
 particular difficulty in getting out of the burrows when ready 
 to change to adults. The length of the pupal life is not 
 very great. The adults commence appearing in midsummer. 
 There is one generation for each year. Treatment for the 
 species has never been very satisfactory. There is no method 
 known at once cheap and effective that can be easily applied. 
 The most effective plan is that of cutting out the larvae 
 from the burrows during the early autumn. A recent plan 
 of mounding the trees and using a barrier applied close to 
 the trunk with an adhesive that is pliable and non-injurious 
 to bark, the collar flaring over the mound, is claimed to be 
 effective. 
 
 In the same family are the currant-, maple-, and syringa- 
 borers. The food plant is rather restricted usually. 
 
 Handmaid Moths. — Genus Datana, and species Datana 
 ministra, have a quite peculiar habit as larvae. The moths 
 are rather neutral-tinted forms and the larvae are quite 
 conspicuous with a gregarious habit. They occur commonly 
 on apple trees and other orchard trees, and where there is a 
 nest of them the trees are badly stripped. They cluster in 
 large masses and work in a company. At the periods of 
 moulting they travel down the trunk to w^ithin a few feet 
 of the ground and all moult at once and leave a large mass of 
 moulted skins which adhere to the bark. After this moulting 
 they travel back up the tree to the leafy portions and have 
 
FAMILY GEOMETRID^ 225 
 
 another period of feeding. There are probably four or five 
 different moults. At the last moult they are two and a 
 half or three inches in length and about as thick as a pencil. 
 They pupate in protected places and remain over winter 
 in this stage, and the moths issue in the early summer and 
 deposit eggs. They are very easil}^ controlled. When 
 clustered during the moulting periods they may be easily 
 gathered and killed. 
 
 Family Geometridse. — The family Geometridoe includes 
 the loopers. The larvae have a peculiar arrangement of legs, 
 the abdominal legs being lost, except the last pair, and the 
 movements being made with the thoracic legs. 
 
 Fig. 175. — Paleacrita vernata: a, male moth; b, female moth; both 
 natural size; c, joints of female antenna; d, joint of female abdomen; e, 
 ovipositor — enlarged. (From Riley, Div. Ent., U. S. Dept. Ag.) 
 
 Canker Worm. — The canker worm is one of the most 
 important of these species economically. These are typical 
 loopers and show some distinct specialization. There are 
 two species closely related, and they are known as the fall 
 and the spring canker worms. The spring form appears as 
 an adult in early spring generally before the foliage is 
 expanded on the trees, and the males and females are very 
 different in their characters. The females are wingless and 
 the males have . broad, thin wings. The females can gain 
 access to the trees only by crawUng up the trunks, and the 
 possibilities of distribution are limited by the distance which 
 the females can crawl. They usually crawl up the trunks 
 of the first tree they reach. The eggs are deposited on the 
 twigs and hatch about the time the leaves are fairly opened. 
 The larvffi are very destructive. In three or four weeks they 
 15 
 
226 LEPIDOPTERA 
 
 become fully developed, and drop to the ground by means 
 of silken threads. They enter the ground for pupation and 
 remain in the ground in the pupal stage through summer and 
 fall and winter. 
 
 The fall canker worm is almost the same so far as the life- 
 cycle is concerned, except that the adults issue in fall. In 
 this species the eggs remain over winter and hatch early in 
 spring. Development is quite rapid and pupating is practi- 
 cally the same as for the other species. The wingless con- 
 dition, and the fact that they must crawl up the trees, gives 
 one method of treatment. Anything that will prevent 
 their going up the tree will protect the trees. Bands of tar 
 
 Fig. 176. — Paleacrita rcrnata: a, larva — natural size; b, eggs — natural 
 size and enlarged; c, side view of segment of larva; d, dorsal view of same 
 —both enlarged. (From Riley, Div. Ent., U. S. Dept. Ag.) 
 
 or oil on cotton will prevent their getting up the trunk of the 
 trees. Small trees may be sprayed with arsenical solution 
 as soon as they begin work in the spring. 
 
 Noctuidse (owlet moths) include an immense number 
 of common moths and a number of them very important 
 species. The common name for the larval forms is cut worm. 
 They differ from Geometers in adult characters and the wings 
 are not so broad but fall close together on the back, sloping 
 down the sides of the body. The hindwings are quite large 
 but are not marked. The larvse are mostly without distinct 
 coverings of hair, usually smooth and some of them subter- 
 ranean in habit. 
 
 One common and destructive species is the boll worm of 
 the South, known in the North as the corn worm or tomato 
 
NOCTUIDM 
 
 227 
 
 worm. The larvse burrow into corn or tomatoes and do a 
 great deal of damage. 
 
 Another important species is the cotton worm {Alabama 
 argillacea) which causes losses of millions of dollars in the 
 cotton crop of the Southern States. Occasionally extensive 
 flights of the moth bring swarms into the Northern States, 
 and sometimes these adults attack fruits such as peaches, 
 but it is not believed that the larvae grow on any Northern 
 plant. 
 
 Fig. 177. — Alabama argillacia: cotton moth on apple. 
 Exp. Sta.) 
 
 (Photo by Ohio 
 
 Army Worm {Leucania uniyuncta). — The army worm is a 
 widely distributed species in this country, only once in 
 twenty or thirty years multiplying in such enormous num- 
 bers as to attract general attention. When it does become 
 abundant grass land is stripped entirely of the green leaves 
 and the insects travel into adjacent fields to complete their 
 growth. They travel in immense hordes and devour all 
 vegetation as they go. Normally they are grass feeders and 
 are found in pastures and meadows and only when they are 
 unusually abundant do they migrate into other crops — wheat, 
 
228 
 
 LEPIDOPTERA 
 
 oats, corn, etc., when they may occasion considerable loss. 
 In oat and wheat fields they may sim})ly cut off the heads. 
 The life-cycle of the species is somewhat varied. It has been 
 reported as passing the winter in various stages — egg, larvae 
 and pupse. The moths appear in the summer and eggs are 
 deposited in late summer or in autumn and probably a good 
 many of the individuals pass the winter in the egg stage. 
 Others become practically grown and then secrete themselves 
 
 Fig. 178. — The army worm (Heliuphila unipuncta): a, full-grown army 
 worm; 6, enlarged view of front of head; c, parent moth; c/, eggs in natural 
 position on grass leaf; e, pupa; e, d, c, about natural size; a, enlarged 
 about one-third. (Rearranged after Chittenden, Bull. 29, Div. Ent., and 
 Comstock, Report of U. S. Ent. for 1879.) 
 
 under the surface of the ground and hibernate. Others may 
 reach pupal stage and still others may reach adult stage 
 before winter. The great majority of the larval forms reach 
 their maturity during May and June, and the greatest 
 devastation usually occurs during the latter part of June 
 and early July. Eggs are always laid in grass land and the 
 larvae begin their growth in the grass. One brood is 
 apparently the rule throughout the northern United States, 
 and the difference in the stages observed during the year 
 
NOCTUIDM 229 
 
 are due to irregularities and not to the appearance of more 
 than one brood. The insect is rather hard to treat economi- 
 cally because of its ordinary grass-feeding habit. When 
 the enormous increase in numbers occurs, the time for check- 
 ing them is really past. Something can be done for treat- 
 ment. One way is to use trenching methods for capturing 
 the larvse as they travel over grass land — trenches put 
 across their line of travel and in this way large numbers 
 may be captured and destroyed. It is also possible to spray 
 the grass in the line of their march with arsenical solutions. 
 These should not be used to pasture stock until the poison 
 has had time to be washed out and no harm will be done. 
 The trenches serve to prevent also the migration into wheat 
 and corn or oat fields if adopted early enough. The species 
 is parasitized quite extensively and when they become 
 abundant the parasites also increase rapidly. Their increase 
 is greater than that of the army worm. In this way there is 
 a great check of the army worm. One of the most important 
 of these parasites is the tachina fly which is closely related 
 to the house fly, blow fly, etc. There are other parasites 
 which are quite valuable also. 
 
 Cut Worms. — The species known generally as cut worms 
 are distributed through several genera and there are a 
 great many species that occur in pastures and meadows, 
 corn lands, and cotton, some of them are very abundant and 
 destructive and some may be considered as annual pests. 
 They usually live primarily upon grass and in the early 
 spring migrate into gardens and cultivated ground, wdiere 
 their destruction becomes very evident. One of the most 
 important preventives is attention to grass land in autumn 
 adjacent to or upon the area that is to be planted in garden 
 or field crops. Tomato plants may be protected by tin 
 cans, or metal strips bent into cylinders and placed around 
 the plants and the cut worms may be killed by distributing 
 bunches of poisoned clover among the plants to be protected. 
 Some of the species are also attracted to light, and captures 
 of the adults will serve some purpose in reducing the numbers. 
 A feature of the work of cut worms not usually recognized 
 
230 LEPIDOPTERA 
 
 is the regular loss in grass lands. In autumn and spring 
 they feed on the grass plants and destroy a much larger 
 amount of the growth of the grass than just what they eat 
 themselves. They cut off the grass and it withers and is 
 lost for either pasture or hay. The plant goes on growing 
 and the injury is often unnoticed by the cultivator even 
 where the cut worms occur by the thousands and the pasture 
 lands must suffer a great deal of loss. 
 
 The life history varies a little in different groups but most 
 of the species that are troublesome occur in the adult stage 
 in midsummer, depositing eggs which hatch in early autumn, 
 and the larvae become practically grown and form little 
 cells in the earth where they hibernate through the winter 
 and issue in the spring and feed upon spring vegetation. 
 Then they pupate in the ground in earthen cells and issue 
 as adults in midsummer, any time from the first of June 
 to the first of August. Different species may occur at differ- 
 ent dates and in some cases it is important to determine 
 the exact time of appearance for the particular species. 
 
 Tussock Moths. — The tussock moths come in a different 
 family and one species which is widely distributed is the 
 white-marked tussock moth {Notolophiis leucostigma) . It 
 is pretty troublesome in orchards and on shade trees, and 
 occurs through the eastern United States and wxst to the 
 plains region. The larvse drop oft' from shade trees on the 
 sidewalks and on people who pass beneath. The larva is 
 the most conspicuous form and much more beautiful than 
 the adult. It is about two inches in length with rather bright 
 yellow markings along the sides and with conspicuous tufts 
 of yellowish hairs on the back and three quite conspicuous 
 long black pencils of hairs, tw^o near the head and one on the 
 tail end, several red spots and numerous whitish hairs. 
 This larva when mature constructs a rather loose cocoon 
 and pupates during midsummer and early autumn and in 
 some cases the moths issue in a few days, in other cases not 
 until the following spring. There are two broods in most 
 cases, in others only one. In the case of two broods, those 
 that appear late in the summer deposit eggs which hatch 
 
TUSSOCK MOTHS 
 
 231 
 
 and the larvae pupate and the moths appear late in the 
 autumn. There is always an autumn deposition of eggs. 
 The females are wingless and the males are winged with plu- 
 
 FiG. 179. — White-marked tussock moth {Notolophus leuco stigma) . 
 forming cocoon. (Photo by Ohio Exp. Sta.) 
 
 larva 
 
 mose antennse. They are gray in color. The females crawl 
 out of the cocoon and do not leave it. After mating the eggs 
 are deposited on the surface of the cocoon. They make a 
 
232 LEPIDOPTERA 
 
 large white mass, the eggs being included in a frothy sub- 
 stance which hardens and forms a varnish-hke coating 
 which ghies tliem to tlie cocoon and protects them througli 
 the winter. The eggs luitch in hite spring or early summer 
 and the larvae grow, passing through several moults and 
 reaching maturity in midsummer or perhaps a little late 
 in summer. This is an insect that is single-brooded in a 
 Northern locality but may easily become double-brooded in 
 a Southern locality. This species is one for which the means 
 of control may be readily seen. Egg masses are quite con- 
 spicuous in the winter and it is an easy matter to gather 
 these in the winter or late fall or early spring, and to destroy 
 them by burning or crushing. The insect's eggs are fre- 
 quently parasitized by minute hymenopterous parasites 
 which lay eggs in the eggs of the tussock moths. These can 
 be allowed to mature and provide another generation of 
 parasites by putting the eggs where there is no vegetation. 
 The parasites when matured escape and the larvse of the 
 moths from unparasitized eggs wdll die. 
 
 Gipsy Moth. — Closely related is the Gipsy moth (Porthet- 
 ria dispar), an important species from Europe. It was 
 introduced about forty-five years ago (1868 or 1869) and its 
 importation was for experimental purposes and not with 
 malicious intent. Eggs or possibly larvae may have been 
 blown out of an open window and the species thus given its 
 freedom. It did not attract much attention for several 
 years. It became abundant near Maiden, Mass., and in the 
 early nineties became quite destructive and attempts were 
 made to exterminate it. In 1898, when its range had been 
 
 LEGEND FOR PLATE. 
 
 Gypsy moth {Porthetria dispar, Linn). (After Massachusetts State 
 Board of Agriculture.) 
 1, female with wings expanded; 2, female in resting position; 3, male 
 with wings expanded; J^, male in resting position; 5, pupa; 6, dorsal view 
 of one of the larger caterpillars, presumably a female; 7, dorsal view of one 
 of the smaller full-grown caterpillars, presumably a male; 8, egg cluster 
 on a piece of bark; 9, a few eggs greatly enlarged; 10, one egg still more 
 enlarged. 
 
/ * 
 
 n 
 
 .^ 
 
 yt 
 
 A ' > 
 
 .i, ' 
 
 JO 
 
 '^ 
 
GIPSY AND BROWN-TAILED MOTHS 233 
 
 much restricted, the State discontinued its efforts, and in a 
 few years it had spread over a large area and its extermina- 
 tion was deemed impossible. A few years later State and 
 National efforts for control were inaugurated and have been 
 pushed vigorously in several different ways. The species has 
 caused great losses, and both State and National govern- 
 ments have spent great sums in attempting to keep it from 
 spreading and increasing. 
 
 The life history of the species is an important factor in 
 control. The moths appear in midsummer and autumn and 
 the males and females differ in appearance but both have 
 wings, though those of the female are weak and their flight 
 is limited. Distribution of the species by the flight of the 
 females seems to be almost nothing, and the spread of the 
 species is mainly by the distribution of caterpillars. The 
 eggs are deposited in late summer and the egg masses sur- 
 vive the winter attached to trees, bark, etc. They hatch 
 in spring or early summer and the larvae make their growth 
 during the early summer months. They may be so numerous 
 as to almost completely strip the foliage of plants. At such 
 times the caterpillars make every effort to scatter, attach- 
 ing themselves to vehicles, etc. There are several parasites 
 for the species, but none which are distinctly effective in 
 this country in keeping the species down. Different methods 
 adopted by the Massachusetts Commission are extremely 
 interesting. A volume has been published on the Gipsy 
 moth. Spraying, burning, scraping of trunks of trees, etc., 
 have all been used. In one instance every inch of an 
 immense elm tree was gone over. Extended efforts have been 
 made to introduce parasites and predaceous enemies to aid 
 in control of the species. 
 
 Brown-tailed Moth. — ^Another species of rather recent 
 introduction is the brown-tailed moth which was first 
 observed in Massachusetts in the vicinity of Boston about 
 the year 1890 or 1891. This is a native of central Europe 
 and is particularly common in France and Germany where 
 it is recognized as a destructive species. The female flies 
 readily, and thus it has spread more rapidly than the Gipsy 
 
234 LEPIDOPTERA 
 
 moth, and now occurs tliroughoiit tlie eastern part of Mas- 
 sacluisetts, New Ilampsliire, and eastward into New Bruns- 
 wick and Nova Scotia, south and west into Connecticut. 
 It is quite certain to spread by degrees througliout a large 
 part of the entire forested portion of North America. The 
 adults are white with the hinder portion of the abdomen 
 brown. The eggs are laid on trees in small clusters and have 
 a brown appearance. The larvse hatch in early autumn and 
 the caterpillars become about half-grown before winter and 
 then spinning up in clusters, form a nest of leaves and web 
 in which they secrete themselves for the winter. In spring 
 with the opening of foliage they wander from these nests, 
 attacking the foliage and causing serious injury, completely 
 stripping the trees, so that they may be killed especially if 
 the attack is repeated for two or three seasons. The larv^se 
 complete their growth by early summer, pupate, and pro- 
 duce moths in late summer, thus completing the annual cycle. 
 The larvse feed exposed on the foliage and may be killed by the 
 arsenical sprays when occurring on orchard or shade trees, 
 where it is possible to reach them with the spraying machin- 
 ery. An evident means of control is to destroy the over- 
 wintering insects during fall, winter or early spring when 
 they should be conspicuous on leafless trees. They are 
 easily shipped from place to place on twigs or small trees 
 and should be excluded by inspection of shrubs, trees, or 
 cuttings that are imported. 
 
 While not at present established as pests outside of the 
 New England States, these insects deserve to be watched 
 and particular pains taken to prevent their dispersal. Such 
 watchfulness may serve to greatly retard the distribution 
 and postpone the time when they may be destructive in any 
 particular region. 
 
 Web-worm Moths. — The web-worm moths are little, white, 
 with femur of front legs of yellow or orange tint, and the 
 legs and feet with little touches of black. These moths are 
 plentiful during the summer — about the last of June. They 
 deposit eggs in masses on the under surface of the leaf. 
 When the young hatch they usually first attack the leaves 
 
TENT CATERPILLAR 
 
 235 
 
 on which the eggs were deposited, enclosing it in a web and 
 the whole colony begins to feed on a single leaf adjacent 
 to it. After the first moult they pass to other leaves and 
 include large numbers of leaves and sometimes the whole 
 tree. The entire colony feeds within the silken web. None 
 of them go away to scatter over the tree. There are several 
 moults, about five. They pupate a little later in the season 
 and the adults issue in the following spring. Two broods 
 are known in some localities. It is a great pest in orchards 
 
 
 ^ Fig. 180. — The fall web worm {Hyphantria cuneo) : a, dark larva from 
 side; &, light larva from above; c, dark larva from above; rf, pupa, ventral 
 view; e, pupa from side; /. adult. All slightly enlarged. (After Riley.) 
 
 and occurs on more than one hundred kinds of plants. The 
 web worms are so conspicuous that there is little excuse for 
 neglecting them and clipping off the newly formed web 
 with the end of the twig infested, or crushing or burning the 
 colony is so simple a matter that no one should permit 
 them to multiply. 
 
 Tent Caterpillar {Clisiocmnpa americana). — This is some- 
 times called the American tent caterpillar. The Western form 
 is called the Western tent caterpillar. They are more com- 
 
236 
 
 LEPIDOPTERA 
 
 mon in orchards than in forests. The}' differ from the fall 
 web worm both in life history and in the character of the 
 tent or web and in the habits of the larvae. The adults are 
 heavv-bodied and hair\', with lon*,^ slender scales. They 
 
 , ^^.. 
 
 ^■xs 
 
 
 
 ik 
 
 »h.. 
 
 
 
 
 
 ^ 
 
 
 ■^ 
 
 ^""^^^^P^ 
 
 
 ^mT 
 
 ^^^^K 
 
 :;^g 
 
 ^ 
 
 1 
 
 0' 
 
 PC ■ 
 
 
 Fig. 181.— Web of fall wob worm enclosing colony. 
 Exp. Sta.) 
 
 (Photo by Ohio 
 
TENT CATERPILLAR 
 
 237 
 
 appear rather early in the autumn, depositing masses of 
 eggs in circles around the twigs, usually completely encircling 
 the twig. The eggs are glued together very firmly with a 
 varnish-like substance that covers and protects them for 
 the winter season. The largest part of the time is spent in 
 the egg stage, that is, through autumn and winter and 
 
 Fig. 182.— Webs of fall web worm (Hyphantria cuned) on defoliated 
 walnut tree. (Photo by author.) 
 
 through early spring. The eggs hatch quite early, about 
 the time the foliage expands or a little in advance of the 
 foliage, and the larvse construct a nest generally in a crotch 
 of a rather fair-sized branch— perhaps an inch and a half 
 in diameter. The web fits into the crotch and extends out 
 beyond it. The web is not much increased after first formed. 
 The larvge scatter when feeding on the leaves and retire to 
 
238 
 
 LEPIDOPTEHA 
 
 the tent for ])r()tcc*ti()n wIkmi not feeding. In this tliey differ 
 from the fall web worm. They have fairly distinct times of 
 feeding and of resting, the feeding l)eing })erhai)s more com- 
 monly done in the early, cooler part of the day, perhaps more 
 or less at night, and protection in the web being sought in 
 the middle of the day or tlie hottest ])ortion. They get their 
 growth pretty rapidly, requiring only a few^ weeks in early 
 spring for their development, and then they scatter mainly 
 
 
 ^g 
 
 ^ d 
 
 Fig. 183. — Stages of the apple-tree tent caterpillar: a, egg mass; b, 
 larva; c, pupa'; d, cocoon; 9, female moth; ^f, male moth. About 
 natural size. (After Quaintance, Div. Ent., U. S. Dept. Ag.) 
 
 from the nest and construct cocoons in all sorts of protected 
 places, under bark, under boards, on fence posts, under 
 ground, etc. The cocoon is rather irregular, not very com- 
 pact and within the cocoon they change to pupae. This 
 pupation or change to the pupal stage takes place soon after 
 the cocoon is formed. They remain in the pupal stage only 
 about three weeks and then issue as moths, coming out in 
 the summer. They do a great deal of damage which is rather 
 more pronounced because of the early attack on the foliage 
 
M^''''4;^ 
 
 
 Fig. 184. — Apple-tree caterpillars (Malacosoma americana) and "nest;" 
 egg mass or belt on small twig at left. "Nest" considerably reduced; 
 caterpillars one-half natural size. (After Quaintance, Div. Ent., U. S. 
 Dept. Ag.) 
 
 (239) 
 
240 LEPIDOPTERA 
 
 before it is fully expanded. A single nest may ser\e to 
 defoliate an entire tree of ordinary size. The method of 
 destroying them will be a little different from that of the 
 fall web worm on account of the habit of scattering over the 
 tree. To kill the entire colony it is necessary to take the 
 time they are all in the nest, when they can be destroyed 
 as easily as the fall web worm. The best way is to destroy 
 the egg masses. The egg masses are conspicuous enough to 
 be readily seen and by destroying them the injury for the 
 following season can be prevented. They are readily con- 
 trolled in this manner. When foliage is on the tree the 
 egg masses are not so readily seen. A little attention for 
 a year or two will practically rid an orchard of these pests. 
 They are heavy-bodied and although winged, do not travel 
 far. The moths are a dark gray or slightly rusty brown 
 and are much like a number of other moths. Two light bands 
 extend across the wing a little obliquely to the axis of the 
 wing. These are bordered by a slightly darker stripe. 
 
 The forest tent caterpillar is very similar in the appearance 
 of the larvae and in the building of the tent but difl'er in the 
 egg masses. The eggs stand straight out; and this species 
 is not so important as the tent caterpillar. 
 
 The Cecropia moth, Luna and American silk worm are also 
 quite prominent, but are not as important economically 
 as the preceding species. All are silk-making forms, but 
 their silk production does not compare with that of the 
 Chinese worm. The silk worm is the most important insect 
 considered from a stand-point of producing an important 
 product — the honey bee is the only other of great impor- 
 tance. The silk industry will perhaps come into greater 
 prominence in this country if labor is cheaper or there is a 
 larger class of unemployed, as it requires a great deal of 
 attention but no great skill of labor. Too much time and 
 trouble are necessary to rear silk worms profitably in a greater 
 part of the United States. In France, Italy, China, and 
 Japan it is a very large industry. 
 
 This finishes what are known as the moths proper — the 
 Lepidoptera which have antennie without an}' knob at the 
 end and which are almost all night-flying. 
 
PAPILIONID/E 
 
 241 
 
 The next group are day-flying, butterflies, etc., and have 
 a different form of antennae. The skippers are somewhat 
 intermediate. Their antennae are slender and run out. 
 sometimes into a hook, or end in a thread-like structure. 
 The butterflies have a thickening at the tip of the antennae. 
 Butterflies are strictly diurnal and are contained within 
 four or five distinct families. Hesperidae are intermediate 
 not only in these antennae but also in the wings. In the 
 
 Fig. 185. — Cecropia moth, larva; natural size. (Photo. Ohio Exp. Sta.) 
 
 butterflies the wings are folded up vertically over the back. 
 In Hesperidae they are about half and half. Some fly at 
 twilight — the yucca-borer — others in the daytime. 
 
 Superfainily Painlionidoe includes the swallow-tailed 
 family. There is a tail-like appendage on the hindwings, 
 which varies considerably in different species. The larvae 
 are most of them characterized by the presence of peculiar 
 fleshy organs which are projected from the segment behind 
 16 
 
242 LEPIDOFTERA 
 
 the head. Tliis fleshy organ is thrown out when they are 
 irritated. It gives oft* a very pecuHar odor characterized by 
 some as Uke the flavor of ripe peaches. This is presumably a 
 protective device. The caterpillars are many of them 
 banded distinctly and others have rather neutral colors and 
 eye-like spots on the body. A large black form with yellow 
 stripes on the wings is one of the most common here. In the 
 South it feeds on the orange and is known as the orange dog. 
 In Northern localities it feeds on the prickly ash and the 
 pawpaw. The caterpillar of this species, Papilio cresphontes, 
 has much the appearance of the excrement of birds. In most 
 of the Northern States the species is rather rare, but in the 
 South is quite abundant. 
 
 Pieris rapse, in the family Pieridoe, is the common cabbage 
 worm or cabbage butterfly. This species was introduced 
 from Europe into America some forty or fifty years ago, 
 probably in the vicinity of Quebec, and has spread over all 
 the eastern United States and practically over all the country. 
 Its life-cycle is pretty definite and the broods are pretty well 
 marked, there being two broods each year. Starting with 
 the adults that appear in spring or early summer, eggs are 
 laid on cabbage or other cruciferous plants and after hatching 
 from the eggs, the larvae develop by midsummer and adults 
 of this generation lay eggs that hatch the latter part of 
 July or in August and develop during August and September 
 or October. This brood feeds particularly on the cabbage 
 heads which may be tunneled through quite well into the 
 interior or at least well through the outer leaves, damaging 
 them for use. The larvae are green in color and well protected 
 either outside or inside of the leaves. The larvae develop 
 through autumn and mature by cold weather by the time 
 that the plants give out and then change to pupa?, the 
 chrysalids being formed in fence corners, sides of buildings, 
 and other protected places. Sometimes they get into build- 
 ings and sometimes simply under rubbish. They are likely 
 to travel considerable distances from the plants on which 
 they have fed. They pass the winter in this stage and the 
 butterflies issue in spring and deposit eggs for the first brood 
 
ALFALFA CATERPILLAR 243 
 
 of larvae upon any of the crucifers available. Early cab- 
 bages may be attacked, the larvse feeding simply on the 
 leaves. Eggs are commonly deposited on wild mustard, etc., 
 and the larvte develop on these plants. The pupal stage for 
 the first brood is quite short, about two weeks to twelve 
 days. There is enough variation in the time of appearance, 
 so that the butterflies may be present for three or four weeks 
 in both spring and summer, and so they are to be found 
 pretty well through the summer months up to the middle of 
 August or the first of September. The great bulk of them 
 come at about the time vegetation is opening up and again 
 about the jSrst of August. The species is not very easily 
 controlled. It lives on a variety of food plants and is two- 
 brooded and this helps in sustaining it. If the first brood 
 could be destroyed it might be controlled, but it is hard to 
 do this. Trap crops may be planted, as mustard, etc., 
 and then the entire crop destroyed after the eggs are deposited 
 on it. Butterflies can be captured while depositing eggs, a 
 cheaper method than applying insecticide. Remedies can 
 be applied to the cabbages, especially before they have 
 headed without any danger to the eating of the cabbages 
 after they have grown. It should be done with precaution, 
 especially after the cabbages have reached some size. If the 
 solution is the right strength, there is practically no danger, 
 as twenty-eight cabbages would have to be eaten at one meal 
 to poison a person. The best way is to apply poison before 
 the cabbages are headed out. If the treatment is pretty 
 thorough for the first brood and the early part of the second, 
 the effect will be pretty successful. Gathering of the pupse 
 is possible, but is not practicable on a large scale. It is 
 better not to destroy these, but to pass them into a receptacle 
 with a wire screen so that the parasites may escape while 
 the butterflies do not. The parasites are sometimes abun- 
 dant and greatly reduce the numbers and in some seasons 
 render the use of remedies unnecessary. 
 
 Alfalfa Caterpillar {Eurymus eurytheme). — The alfalfa 
 caterpillar is a common species over most of the United 
 States and has attracted attention as a serious pest in the 
 
244 
 
 LEPIDOPTERA 
 
 alfalfa-growing districts of the West and Southwest. In the 
 Eastern States it is less abundant but still plentiful enough, 
 
 Fig. 186. — The alfalfa caterpillar (Eurymus eurytheme) : female in the 
 adult or butterfly stage. One-half enlarged. (After Wildermuth, Bur. 
 Ent., U. S. Dept. Ag., Fig. 2.) 
 
 Fig. 187. — The alfalfa caterpillar {Eurymus eurytheme) : male in the adult 
 or butterfly stage. One-half enlarged. (After Wildermuth, Bur. Ent., U. 
 S. Dept. Ag., Fig. 3.) 
 
 SO that it must have an effect on the clover crop on which 
 the larva feeds. 
 
MONARCH BUTTERFLY 
 
 245 
 
 In the Eastern Mississippi Valley and Atlantic Coast 
 States it is perhaps less common than the related sulphur 
 butterfly, Colias philodice, which is so plentiful as adults 
 that it is fair to assume an abundant progeny feeding in 
 clover fields. 
 
 W 
 
 wi JR W Hk^p^bII 
 
 Fig. 188 
 
 Fig. 189 
 
 Fig. 188, — The alfalfa caterpillar: egg — greatly enlarged. (After Wilder- 
 muth redrawn from Soudder, Bur. Ent., U. S. Dept. Ag., Fig. 4.) 
 
 Fig. 189. — The alfalfa caterpillar (Ewymus eury theme) : larva or cater- 
 pillar stage — about twice natural size. (After Wildermuth, Bur. Ent., U. 
 S. Dept. Ag., Fig. 1.) 
 
 Fig. 190. — The alfalfa caterpillar {Eurymus eurytheme) : pupa or chrys- 
 alis stage — twice natural size. (After Wildermuth, Bur. Ent., U. S. Dept. 
 Ag., Fig. 5.) 
 
 Monarch Butterfly {Anosia plexippus). — The monarch but- 
 terfly (family Danaidce) is interesting in two or three ways, 
 though not of any special importance economically. It is 
 one of the largest butterflies outside of the Papilios, and it 
 
246 LEPIDOPTERA 
 
 is pretty readily rec()f]jni/e(l })y tlie dark re(ldisli-})r()wii color 
 with black bands and stri})ings and the border including a 
 number of white sj)ots. It deposits eggs on milkweed as its 
 host plant. These eggs hatch very shortly and the larvtTe 
 develop during the latter part of the summer and i)upate 
 and become adults in autumn, and it is quite common in 
 October to see immense swarms of these butterflies. They 
 gather along hedge rows and on trees, sometimes appearing 
 by millions. Late in the afternoon they will cluster on the 
 branches in immense numbers. At the time of their gather- 
 ing in immense numbers they seem to have a general south- 
 erly movement and they are known to migrate at least to 
 some extent during the autumn, though the migrations 
 probably do not cover as long distances as that of birds — 
 not over 200 to 500 miles. They appear in great abundance 
 in the South in the winter. It is not possible to follow indi- 
 viduals for very great distances, but evidently they hibernate 
 in the adult stage in the South and it is pretty generally 
 believed that the hibernating individuals in Northern locali- 
 ties are likely to perish. Individuals that start the first 
 generation must have travelled from the South. The spring 
 individuals are frayed and give evidence of having travelled 
 some distance. The spring-appearing individuals deposit 
 eggs and from these the generation of caterpillars comes 
 that mature during midsummer. The adults appear in the 
 latitude of New York about the middle or last of July. 
 There are two distinct generations for each year. The cater- 
 pillar is quite prominently banded and has some striking 
 thread-like appendages. It reaches the length of one and a 
 half or two inches and is nearly as thick as a pencil. It is 
 found particularly on the milkweed. Their pupation occurs 
 by attachment to the leaves of the milkweed or plants or 
 objects convenient or adjacent to the host plant. The pupa 
 cases are attached by a sort of spur or hook at the posterior 
 end of the body caught into a little web that has been spun 
 on the leaf. The larvse locate on a suitable object and spin 
 a little web and then the larva contracts and the larval skin 
 splits along the back and this larval skin is held by the pos- 
 
NYMPHALIDM 247 
 
 terior segment in such way that it can twist the pupa case 
 around and catch the hook of the pupa case into the web. 
 The pupa case lasts only a week or ten days and then gives 
 rise to the adult form. It is mimicked by a species which has 
 an additional black band on the hindwing and there are 
 differences in the legs. This, the viceroy (Basilarchia 
 archippus) has evidently gained protection by taking on 
 the appearance of the monarch. 
 
 One other species in the family Nymphalidw that should 
 be noticed is the common mourning cloak vanessa {Euvan- 
 ess a antiopa) which is interesting because of its very wide 
 distribution and its very great hardihood. It is said to occur 
 over practically all of the northern hemisphere from 30° to 
 the Arctic Circle. It occurs here in the winter time, hiber- 
 nating as an adult and has been found secreted in hollow 
 logs, bridges, and in almost any sheltered place, and if 
 taken indoors will revive and feed on sweetened water 
 quite readily. They begin to fly quite early in the spring. 
 It is double-brooded — the eggs deposited in early spring 
 produce larvae which mature in midsummer. They breed 
 on willow particularly and the larvse are dark-colored and 
 rather conspicuous. They also infest poplar, elm, and 
 dogwood, but willow seems to be the favorite. The chrysalis 
 is attached to the twigs of these plants and the adults 
 appear in midsummer. These adults deposit eggs and a 
 second generation appears in autumn which hibernates and 
 carries the species over winter. In some places they have 
 an economic importance, but ordinarily they are not a 
 serious pest, and the butterfly is such a handsome species 
 that it may be counted as deserving immunity. 
 
CHAPTiP:R IX. 
 ORDER DIPTERA. 
 
 Tins is a very large and important order and includes a 
 number of important economic species such as the house 
 fly and the mosquito. They are separated from all other 
 insects by the wing structure, the front wings only being 
 fully developed as means of flight and the second wings 
 being modified into knob-like structures which seem to. have 
 some use in sustaining the insect in a certain position. 
 They vibrate but cannot serve any distinct function as a 
 means of flight. They are modified wings. This is a case of 
 specialization, reduction in size. This is coordinated with 
 the centralization of the nervous system. There is distinct 
 metamorphosis whose stages are usually sharply marked. 
 The larvae are usually called maggots, those of the mosquitoes 
 "wrigglers." The larvse occur in all manner of situations. 
 Some are aquatic, some terrestrial, some subterranean, etc. 
 The group is separated mainly by larval characters — one 
 group including mosquitoes and gnats, another the more 
 specialized flies. The larva contracts and the skin hardens 
 and forms a pupal case whose end splits off like a cap. 
 
 The Orthorapha, mosquitoes and gnats, are the less 
 specialized or the more primitive group. 
 
 Of the groups in the first series the mosquitoes (CulicidcB) 
 are the most in evidence, if not the most important, and 
 are receiving more attention lately because of their asso- 
 ciation with the transmission of various diseases. The 
 mosquito is not a single species. There are a great many 
 different species and they differ a great deal in life history 
 and habits and in their relation to disease. The most general 
 statement to be made regarding their cycle is that the eggs 
 ( 248 ) 
 
MOSQUITOES 
 
 249 
 
 are deposited on the surface of the water and perhaps in 
 some species in mud or damp earth. The larvse are essentially 
 
 Fig. 191. — Anopheles maculipennis: male. Fig. 192. — Anopheles maculi- 
 
 Carrier of malaria. (Harrington.) pennis: female. Carrier of 
 
 malaria. (Harrington.) 
 
 Fig. 193. — Anopheles punctipennis: male. 
 Howard.) 
 
 Carrier of malaria. (After 
 
250 
 
 ORDER DIPTERA 
 
 aquatic and air-l)roathin<]j, witli tlie trachea opening at the 
 end of tlie abdomen. TJie \)\\\)iv are also acjuatic but keep 
 near the surface and spiracles o])en near the head. The pupa 
 case splits on the dorsal side and the mosquito rests on the 
 
 Fig. 194. — Anopheles^ punctipennis: female. (From Howard, 
 Div. Ent., U. S. Dept. Ag.) 
 
 surface of the water until its wings are dried enough for flight. 
 One species has been observed whose eggs may remain over 
 winter in mud, and hatching and development depends upon 
 the presence of water. Mosquitoes breed in minute quanti- 
 
MOSQUITOES 
 
 251 
 
 ties of water if they have it for a few days, and especially 
 those that are more common about towns depend on small 
 pools, tanks, and rain barrels rather than larger bodies of 
 water. More breed in small pools than large, because there 
 are usually no fishes in the small pools. They fly for a few 
 rods but for no extreme distance — one-half mile or a mile. 
 
 <^^' 
 
 Fig. 195. — Culex tceniorhynchus: female showing the short palpi which 
 distinguish Culex from Anopheles; toothed front tarsal claw at right — 
 enlarged. (From Howard, Div. Ent., U. S. Dept. Ag.) 
 
 They may be transported, but most annoyance comes from 
 those bred close at hand. The connection between mosqui- 
 toes and malaria has been fully established. The parasite 
 seems to be dependent upon two distinct hosts. Unless 
 there is a case of malaria in the near vicinity they cannot 
 communicate it to another. The relation of mosquitoes to 
 yellow fever has also been w^orked out very carefully. One 
 
252 
 
 ORDER DIPTERA 
 
 Fig. 196. — Resting positions of Culex (at left) and Anopheles (at right) — 
 enlarged. (Redrawn from a rough sketch published in the British Medical 
 Journal.) (From Howard, Div. Ent., U. S. Dept. Ag.) 
 
 Fig. 197. — Yellow-fever mosquito (Stegomijia fasciata) : A, male; B, 
 female. (After Howard.) 
 
GALL GNATS 253 
 
 striking thing is the discovery of the immense number of 
 species of mosquitoes. There have been many new species 
 discovered in the last few years. 
 
 Gnats {Chironomidce) . — Gnats are related to mosquitoes 
 and are interesting partly because of their close resemblance 
 to mosquitoes and partly because they occasionally multiply 
 so as to cause annoying contamination of reservoirs or 
 obstruction in water tanks. The antennae are plumose as 
 in the mosquitoes but the mouth parts are different. The 
 larvse are more distinctly aquatic than the mosquito larvae — 
 can survive down in the water without coming to the sur- 
 face for air. Some live in mud — slender red, worm-like crea- 
 tures. One species is quite plentiful in the Northern States 
 especially near lakes and sometimes as abundant as the May 
 flies. 
 
 Gall Gnats. — The next group is the one including the gall 
 gnats. It is a very important family with two or three very 
 important species. The most conspicuous of the galls 
 produced by these is the cone g^ll produced on willow trees — 
 the pine cone willow galls. These are the result of the work 
 of the larvae of the gall gnats. They are made up of a series 
 of leaves which overlap in the form of a pine cone. These 
 correspond with the leaves that would have come out along 
 the twig had it grown out normally. The leaves are devel- 
 oped close together and the larvae of the gall gnat is found 
 in a little cell in the centre of the gall. It issues in the spring 
 and deposits its eggs in the willow buds before the twigs 
 have started to grow, and the larvae hatch and form the galls 
 b}^ feeding. There are a good many things in these galls 
 besides these larvae. Other insects find them a convenient 
 shelter, and other insects deposit eggs there. The tree 
 crickets are an example of this. These may be a little mis- 
 leading but they have nothing to do with the formation of 
 the gall. The pine cone gall is most conspicuous. There 
 is another species which simply produces an aborted growth 
 that looks like Brussels sprouts. 
 
 The other species in this family to be mentioned are the 
 clover and wheat midges and the Hessian fly. 
 
254 
 
 ORDER DIRTERA 
 
 Clover-flower Midge {T)asyncura Icguviinicola). — The clover- 
 flower iiiidn'c^ lives within the heads of clover and feeds upon 
 the clover bloom and seed. Its life-cycle is adapted to the 
 
 Fig. 198. — The clover-flower midge {Daayncura legtuninicola) : n, enlarged 
 dorsal view of male with scales denuded; b, head; c, genitalia; d, antennal 
 joints, more highly magnified, to show structure; e, tarsal claw; /, /, forms 
 of scales. (From Riley, Div. Ent., U. S. Dept. Ag.) 
 
 blooming of the clover, so that the larviie appear at the })roper 
 time for feeding upon the clover seed. There are two fairly 
 distinct broods each season, the first brood of larvae develop 
 
HESSIAN FLY 255 
 
 in early summer and mature in midsummer, the larvse issuing 
 from the clover heads and pupating in the ground and the 
 second brood appearing later in the summer and depositing 
 eggs which produce the second generation of larvae which 
 develop in the later blooming clover. These hit the crop 
 of clover grown for seed. They mature with the late autumn 
 and either maggots or the mature puparia would be found 
 during the winter time and the larvae particularly which are 
 caught before they have completed their growth may be 
 included in clover seed. The fully developed larvae pass 
 into the pupa stage at the surface of the ground. It is 
 doubtful if the midge can be transported from one place to 
 another by means of the clover seed. Just how it is intro- 
 duced into remote districts is uncertain. Its means of loco- 
 motion is by its own flight. It is pretty generally dispersed 
 throughout the portion of the country where clover is now 
 grown. The means of treatment would lie more in the 
 direction of cutting the clover at the time to cut short the 
 growth of the larvae — a little earlier cutting of the clover, 
 catching the larvae before they have issued from the clover 
 heads. 
 
 Hessian Fly (Mayetiola destructor), — The Hessian fly is 
 the most destructive of the family. It is an introduced 
 species and was first described from materials in this country 
 in 1820. It probably originated where wheat did. It was 
 never described scientifically until by Say. It had been 
 known as a destructive insect earlier than 1820 and the 
 name was given to it about the time of the Revolution, when 
 the Hessian soldiers were in this country, either because the 
 insect was thought to have been introduced by them or as 
 an obnoxious name. The name was adopted over the entire 
 English-speaking world. The evidence that it is an old- 
 world species is from its food plants and that it spreads 
 from one centre. There are a number of other evidences. 
 Its natural food plants seem to be limited to wheat, rye, and 
 barley, though there is a question as to barley. It was 
 proved by a Frenchman that it does not occur on oats. At 
 one time it was thought to breed in various grasses, but later 
 
250 
 
 ORDER DIRT ERA 
 
 studies show that this was not the true Hessian fly. If any 
 attempts are made to control it by rotation of crops its 
 restriction of food plants should be well known. Its life- 
 qycle is quite similar to that of the clover-flower midge and 
 it has become very distinctly adapted to the crop it infests. 
 Any great change in ordinary methods of raising wheat 
 would likely prove destructive to the insect. The winter is 
 
 Fig. 199. — The Hessian fly (Mayetiola destructor) : adult female — much 
 enlarged. (After Webster, Div. Ent., U. S. Dept. Ag.) 
 
 passed in the flaxseed stage — the puparium stage. The 
 larval skin shrinks and forms a tough, dark brown covering 
 about the size and shape of a flaxseed. Within this there 
 is formed a real pupa that has the outline and features of the 
 adult insect. There is a distinct metamorphosis. These 
 hibernating puparia give rise in early spring to adult midges 
 that deposit eggs on the stems and leaves of wheat plants — - 
 
HESSIAN FLY 
 
 257 
 
 winter wheat. In spring wheat regions the flies appear 
 at about the time of the coming up of the wheat and deposit 
 eggs on it. There is not necessarily much difference in the 
 time and method of deposition except that those on winter 
 wheat are apt to be a httle higher on the stems and farther 
 from the ground. These burrow into the stem in such a 
 way as to cause weakening of the stalk, which is apt to bend 
 
 Fig. 200.— The Hessian fly: 
 Marlatt, Div. 
 
 adult male — much enlarged. (After 
 Ent., U. S. Dept. Ag.) 
 
 and break as it approaches maturity and falls to the ground, 
 so that it cannot be harvested. Sometimes only 1 or 2 per 
 cent, of the field will be infested and in other fields one-third 
 or one-half of the crop will be lost. As the wheat matures 
 the larvae mature and change to the flaxseed stage and 
 remain protected between the sheath and the stem of the 
 plants down near the ground. Sometimes they are 
 17 
 
 high 
 
258 
 
 ORDER DIRTERA 
 
 enough to be cut off aud carried witli the straw when the 
 wheat is luirvested, })ut more commonly are left in the 
 
 i 
 
 Fig. 201. — Egg of Hessian fly — greatly en- 
 larged; section of leaf of wheat, at right, 
 showing eggs as usually deposited, less 
 enlarged. (After Webster, Div. Ent., U. S. 
 Dept. Ag.) 
 
 Fig. 202.— The Hess- 
 ian fly: larva before "flax- 
 seed" is formed — much 
 enlarged. (Webster, Div. 
 Ent., U. S. Dept. Ag.) 
 
 Fig. 203. — The Hessian fly: larva 
 taken from "flaxseed," much enlarged 
 with "breast-bone" still more enlarged 
 at right. (After Webster, Div. Ent., 
 U. S. Dept. Ag.) 
 
 Fig. 204. — The Hessian 
 fly: puparium or "flax- 
 seed," much enlarged. 
 (After Webster, Div. 
 Ent., U. S. Dept. Ag.) 
 
 stubble. They survive the midsummer in this condition and 
 are apparently dependent more or less on conditions of 
 
HESSIAN FLY 
 
 259 
 
 temperature and moisture. They come out in the fall and 
 are ready to deposit eggs on wheat plants accessible in the 
 
 Fig. 205. — The Hessian fly: pupa taken from "flaxseed," greatly 
 enlarged. (After Marlatt, Div. Ent., U. S. Dept. Ag.) 
 
 Fig. 206. — Injured plants and flaxseeds. (Photo by Ohio Exp. Sta.) 
 
260 ORDER DIPTERA 
 
 autumn. The eggs deposited in tlie autumn give rise to larvse 
 which develop and ])ass into the flaxseed stage to hiberuate. 
 If they are accelerated in their development and are provided 
 with food material — volunteer wheat — there may be one or 
 more extra broods in the summer. As high as five or six 
 extra broods were observed by Marchal. Tliere are ordi- 
 narily two broods adjusted to the occurrence of young wheat 
 plants. One important thing is the distribution of the 
 species by means of the shipping of infested straw. This 
 must be the main or only means by which the species is 
 taken from one country to another. It has been introduced 
 into most wheat-growing countries of the world. The 
 natural distribution of the species is limited to about 20 
 miles a year. Flight aided by the wind might carry it some 
 little distance. For local measures attention to the stubble 
 is one of the most important things. If it is thick and dry 
 enough to burn over during midsummer, it can be destroyed 
 in this manner. Plowing under very deeply is another 
 method but must be done early enough to bury the stubble 
 before the flies have issued. The most generally practised 
 method, and most highly recommended, is to adjust the time 
 of planting so as to avoid the period of egg deposition. If 
 the time of planting wheat can be deferred for a week or two 
 after the appearance of the flies, it will escape. Flies will 
 not deposit eggs on the bare plowed field. If the wheat comes 
 up after the flies have issued and passed the egg-laying period, 
 it escapes attack. For the Central States the time of appear- 
 ance has been pretty definitely determined, and it has been 
 shown at what time wheat can be planted with the greatest 
 security. For the latitude of Columbus, Ohio, it is about 
 the first of October. It is possible to plant trap crops so as 
 to catch the flies as they appear and the whole crop can be 
 plowed under after the eggs are deposited on it. This is not 
 particularly popular. If planting is done with reference 
 to temperature and to different seasons, results will be better. 
 Hot, dry weather seems to prevent the issuing of the flies. 
 Family Simuliidse.— The family SivudiidcB includes the 
 black flies and buffalo gnats. These constitute extremely 
 
FAMILY SIMULIID^ 261 
 
 injurious pests and occasion many losses to agriculturists, 
 so that they deserve a paragraph at this point, although for 
 most of their existence they have very little in common with 
 farm life. They have had an added interest in recent years 
 on account of the effort to prove them the carrier of the 
 disease known as pellagra, but proof of such a connection 
 is still wanting. The adults are short, small, thick-bodied 
 insects; the thorax especially heavy, and the humped appear- 
 ance of the whole body has given rise to the name buffalo 
 gnats. They are all small species, scarcely any of them a 
 quarter of an inch in length. The larvae are distinctly aquatic, 
 usually living in swiftly running water. They are so fully 
 adapted for aquatic life that they attach themselves by 
 silken threads to submerged objects and depend for their 
 food upon minute organisms floating or swimming in the 
 water. The pupal stage is also passed under water, a thin 
 cocoon being spun upon the under side of the leaf or other 
 submerged object. When the adults emerge from these they 
 rise rapidly to the surface of the water, the wings expanding 
 promptly, and they are ready for flight almost instantly. 
 At times they occur in enormous swarms and the females 
 are very blood-thirsty, attacking all kinds of warm-blooded 
 animals, sometimes with very disastrous results. In the 
 Northeastern States and in parts of Canada, especially in 
 Labrador, there is a species known as the black fly. They 
 occur at times in such abundance as to make it practically 
 impossible to remain out of doors, and domestic animals will 
 seek any possible shelter in order to avoid the attacks of the 
 insect. In the Southern Mississippi Valley there are two 
 common species which have been studied in detail. One of 
 these, the turkey gnat, is said to make its attacks very gen- 
 erally upon poultry, although it is not limited to these animals. 
 
 The other species which is credited with the greatest 
 amount of loss in the Mississippi Valley region may be 
 considered somewhat in detail and as a representative for 
 the family. 
 
 Southern Buffalo Gnat (Sivmlumi pecuanim, Riley). — The 
 investigations of 1885-86-87, which have been reported very 
 
262 
 
 ORDER DIPTERA 
 
 fully in the Department j)ul)lic'ati()ns, and from which the 
 statements here made are mostly compiled, liave shown 
 that the extent of territory invaded by these insects is much 
 greater than formerly su])])osed. It may be stated to com- 
 prise, in the worst years, the whole of the Mississippi Valley 
 from the mouth of the Red River, in Louisiana, to St. Louis, 
 Mo. All the adjacent land to the many rivers and that 
 empty from the east and the west into the Mississi])pi River 
 
 Fig. 207. — Simidium pecuarum: larva — enlarged. (From Annual 
 Report of Department of Agriculture, 1886.) 
 
 is invaded by swarms. They are driven about by the wind 
 and reach points far aw^ay from their breeding places. 
 
 The extent of the losses due to this species has already 
 been stated, though it is, of course, impossible to separate the 
 losses due to this species from those caused by the turkey 
 gnat. Li a general way the latter may be said to be more 
 destructive to poultry, while the attacks of this species are 
 more particularly directed against the larger domestic 
 animals. 
 
FAMILY SIMULIIDM 
 
 263 
 
 The larva is not differeint in general appearance from that 
 of other species. The annexed cut (Fig. 207) shows it con- 
 siderably enlarged and will make a detailed description 
 unnecessary. It is translucent when living; the body in 
 
 \7l\ 
 
 : i 
 
 Fig. 208. — Sinmlium pecuarum: head of larva: a, beneath; b, side; 
 c, above — greatly enlarged. (From Annual Report of Department of Agri- 
 culture. 1886.) 
 
 Fig. 209. — Simulium pecua- 
 rum: pupa — enlarged. (From 
 Riley.) 
 
 Fig. 210. — Simulium pecua- 
 rum: female, side view — en- 
 larged. (U. S. Dept. Ag.) 
 
 some individuals is without markings, while in most it is 
 distinctly marked with dark cross bands on the back in the 
 middle of the joints, while at each side is a white space; 
 the under side is more or less irregularly spotted with brown. 
 
264 
 
 ORDER DIPTERA 
 
 The head is yellowish-brown, nearly square, horny, and 
 marked as in the figure (Fig. 208). 
 
 The tip of the abdomen is crowned witli rows of hooks, 
 and on the upper side of the abdomen is the set of breathing 
 organs, which have been mentioned heretofore. 
 
 The larvae are found more particularly attached to sub- 
 merged logs, wholly or partly submerged stumps, brush, 
 bushes, and other like objects in the larger creeks and bayous 
 of the region to which they are common. 
 
 Fig. 211. — Simidium pecuarum: head of male at right; head of female 
 at left — greatly enlarged. (From Annual Report of Department of Agri- 
 culture, 188G.) 
 
 When fully grown the larvae descend to near the bottom 
 of the stream, sometimes eight to ten feet, to make their 
 cocoons. 
 
 The cocoon upon these leaves is conical, grayish or brown- 
 ish, semitransparent, and has its upper half cut square off, 
 more or less ragged, as if left unfinished. Its shape is irregu- 
 lar, the threads composing it very coarse, and the meshes 
 rather open and ordinarily filled with mud. They are not 
 always fastened separately, but frequently crowded together, 
 not forming, however, such coral-like aggregations as in some 
 of the Northern species. The larva in spinning does not 
 leave its foothold, but running in the centre of its work, uses 
 
FAMILY SI MV LI I Dm 265 
 
 its mouth to spin this snug little house. In it, it changes to 
 a pupa, which has its anterior end protruding above the rini. 
 
 They remain in the pupa state but a short time. Both 
 larval and pupal skins remain in the pouch for some time. 
 
 The adult fly on emergence from the pupa rises quickly to 
 the surface, and the wings expanding almost instantly, it 
 darts away. 
 
 The time of the appearance of the swarms is regulated by 
 the earliness or lateness of the spring, and consequently it 
 is much earlier in the southern parts of the Mississippi 
 Valley. As a rule they can be expected soon after the first 
 continuous warm weather in early spring. In 1885 the first 
 swarms were observed in Louisiana March 11, in Mississippi 
 and Tennessee May 1, and in Indiana and Illinois May 12. 
 
 Horse Flies ( Tahanidce) . — Horse flies are pretty well known 
 and quite important economically. They cause annoyance 
 to domestic animals and to man. They are not credited with 
 carrying any disease, but seem to be w^ell adapted to such a 
 performance. They are aquatic in the larval stages so far 
 as the larvae have been studied, and the larvae are carnivorous 
 and seem to feed on a variety of aquatic life, dead or alive. 
 They pass through pupa stages in the mud or deeper in the 
 marshes of pools and ponds. The adults are very active 
 and swift flying. The eyes occupy practically the whole 
 head and are composed, especially in the males, of an enor- 
 mous number of facets. The females are the biting members 
 of the family, having the mouth parts much more fully devel- 
 oped. The males live on plant juices, but probably do not 
 feed extensively in the adult stage. The females seem quite 
 blood-thirsty, though perhaps this is not a necessary food. 
 The eggs are deposited in little clusters or masses on aquatic 
 plants, usually just above the surface of the water, so that 
 the larvae on hatching at once enter the water. The insects 
 of this group are much more abundant where there is an 
 area of water surface to provide the water habitat. The 
 females gather to the water probably to secure water in con- 
 nection with the deposition of the eggs, and a Russian ento- 
 mologist proposed the plan of putting kerosene on the surface 
 
266 
 
 ORDER DJPTERA 
 
 of the pools to destroy the a(hilt females, and this seems to 
 have been very successful. The trouble in this is that the 
 kereosene kills other forms of life which are not obnoxious. 
 There are several species in this locality. The species com- 
 mon about horses are the green heads and the big black flies. 
 The green heads sometimes cause a great deal of trouble. 
 
 The remaining families of the order come in the suborder 
 Cyclorhapha. This group includes an immense number of 
 flies, many different families and some of the families an 
 immense number of species. 
 
 Fig. 212. — Tabanus atratus: a, larva; 6, pupa; c, adult. (After Riley.) 
 
 The first important family in the group is that known as 
 the SyrphidoB. This one family presents about as great a 
 variety of life, habit and conditions as any in the order. 
 There is everything from aquatic to arboreal species in the 
 larvae. The rat-tailed forms which live in liquid have a long 
 tube extending to the surface of the liquid. Another species 
 occurs on trees. The more important economically are 
 the ones that feed on plant lice, and these are a most impor- 
 tant factor of control. Many species mimic members of 
 other groups of insects. Some look very much like wasps, 
 
FAMILY OESTRIDM 
 
 267 
 
 others like bees, and the rat-tailed species {EristaUs tenax) 
 looks like a drone bee. 
 
 Bot Flies {Oestridoe). — The bot flies are parasitic in various 
 mammals, occupying the body tissues and primarily the ali- 
 mentary tract. The adults are bee-like, with rounded heads 
 and small eyes, and are hairy. The antenna? are sunken into 
 little pockets or pits in the front of the head, and the mouth 
 ])arts are aborted. The adults do not feed. The females are 
 
 Fig. 213. — Horse bot fly (Gastrophilus eqiii): a, egg, enlarged; b, nat- 
 iiral size; c, larva, newly hatched, enlarged; d, more enlarged; e, oral 
 hooks; /, body spines; g, mature larva, twice natural size; h, adult female. 
 (Author's illustration. Bur. Ent.. U. S. Dept. Ag.) 
 
 the more commonly seen and they deposit their eggs on the ani- 
 mals that are to serve as hosts for the larvae. The males gener- 
 ally remain in shady places among grass, etc., so that they are 
 much less likely to be observed. The larvae seem to have 
 adjusted themselves to the parasitic condition from a more 
 primitive condition, possibly that of living in organic matter 
 of some kind. It seems most likely that some form with 
 habits perhaps like the blow fly might in some cases deposit 
 
268 ORDER DIPTERA 
 
 eg^s in siK'li ])la(*es tliiit the larvtie would survive and the 
 liabit grachially acquired of hving within the liost tissues. 
 They reacli maturity without destruction of the host form 
 and the habit gradually becomes fixed. This habit is now 
 definitely fixed among all the species of the family and 
 they are restricted to mammals as hosts. Some infest the 
 alimentary canal, some the nasal passages, some the tissue 
 beneath the skin. The larvtie as parasites have undergone 
 considerable modification from the primitive forms. They 
 are usually provided with rows of spines or sharp spurs that 
 assist their movements when they leave the host forms and 
 for those that live in the alimentary canal there are hooks, 
 modifications of the mouth parts, that serve to attach them. 
 They may feed to some extent upon the secretion of the host, 
 but most of the nutrition is absorbed through the body walls. 
 The Horse bot fly {Gastrophilus equi) is one of the best 
 examples and probably represents most nearly the primitive 
 condition for the family. The adult occurs through the middle 
 and last of summer and the eggs are deposited on the hairs of 
 the horse, small yellow eggs glued very firmly to the hairs. 
 In depositing the eggs the female darts toward the animal 
 and thrusts the egg against the hair without alighting. The 
 abdomen is thrust forward under the body. A glutinous 
 secretion is discharged with the egg and binds and hardens 
 almost immediately. The eggs are very thick-walled with 
 chitinous walls and have a little operculum or cap at the end 
 of the egg which is easily detached after a certain stage in 
 the development. The time for hatching varies from three 
 days to forty, but usually ten to fifteen days after deposition. 
 Before that time they are hatched with a great deal of diffi- 
 culty, and the larvae are rather inactive. x\fter fifteen to 
 twenty days the activity begins to diminish. The majority 
 die if not hatched in thirty to forty days. They do not 
 hatch without the assistance of moisture, friction, and 
 warmth to stimulate the larvae. With a little moisture and 
 friction the cap slips off easily and the hooks of the larva 
 fit it to attach itself immediately to the tongue or other part 
 of the body of the horse. The egg shells remain on the hair 
 
FAMILY OESTRID^ 269 
 
 after the hatching occurs. The time for the hatching of the 
 eggs is rather important with regard to the treatment of 
 the animal. It has been studied pretty carefully. Different 
 statements as regards the period of incubation may mean 
 different species observed. Egg deposition may go on until 
 quite late in autumn, but is usually at its height about 
 August or early September. The activity is retarded by cold 
 weather and the larvae may survive longer then. The method 
 by which they get into the stomach of the horse is by the 
 horse licking itself or some other animal on which there are 
 eggs. At first they are long and slender but after attachment 
 in the stomach become thicker and fasten themselves by 
 hooks to the stomach and remain there through late autumn 
 and winter and early spring. They are sometimes very 
 thickly set in the stomach of the horses. They must cause 
 considerable interference with the activity of the stomach, 
 and if massed together at the pyloric orifice may act as an 
 obstruction. The effect on the animal is in some cases quite 
 evident. The damage is doubtless different in different 
 animals. The worst infested are those that have been in 
 pasture. When they have completed their growth in the 
 stomach they loosen their hold and pass out of the stomach. 
 They burrow into the ground and pupate and remain in this 
 condition several weeks — six or seven — and issue from mid- 
 summer to early autumn. There is one generation a year 
 and the longer period is spent in the body of the animal. 
 
 Treatment for the larvse is rather severe. They may be 
 killed with turpentine, but care must be used not to injure 
 the horse by an overdose. The means of prevention are 
 indicated by the life-cycle — condition of the egg and length 
 of time it may develop. If eggs are removed every week or 
 ten days there is no danger of serious infection. Horses 
 curried regularly are not apt to be infested. They may be 
 shaved off, and this is the most ready means of preventing 
 the infection. Washes could be used to kill the larvae — 
 kerosene, carbolic acid, etc. 
 
 There are three or four species of this parasitic genus in 
 the horse, but no other so common as Gastrophihis equi. 
 
270 
 
 OUDKli DIPT ERA 
 
 They cause a ^ood deal of annoyance. One is called the chin 
 fly {GaMrophilnfi na.s'alis), which lays eggs on the jaws. 
 Another, the red-tailed hot fly {(iastwphihis hwmorrhoidnlh), 
 also deposits eggs in the vicinity of the mouth. 
 
 Bot Fly of the Ox ( Ilypoderma lineaia). — The hot fly of the 
 ox illustrates another method of development, but seems 
 to have been derived from that of the one occurring on the 
 horse. It is known in some parts of the country as the 
 Texas heel fly. It occasions a great deal of loss to the cattle 
 
 Fig. 2\^.—H ypoderma lineata: female — natural size indicated by side 
 line. (From Insect Life.) 
 
 industry. The larv&e perforate the hides. They develop 
 under the skin and on maturing pass through the skin, 
 leaving a lot of openings. Such hides are docked one-third 
 in the market. Eggs are laid on the hairs of the legs, and as 
 he found none on the hairs of the back, Dr. Curtice concluded 
 that the larvae were taken into the mouth and travel by way 
 of the esophagus and through the tissues of the thoracic 
 region up through the tissues of the back as their normal 
 route. The puncture is made after the larva is under the 
 
FAMILY OESTRID.^ 
 
 271 
 
 Fig. 215. — Hypoderma 6oi'is— enlarged. (After Brauer.) 
 
 Fig. 216. — Piece of warbled hide — warbles about half size. (After 
 Omerod.) 
 
272 
 
 ORDER DIPTERA 
 
 skin and some time before it is ready to issue. Tlie adults 
 appear quite early in the season and the hirvse in the hacks 
 of cattle are never seen until in the winter time — January 
 first to ]\Iarch or April. They cause the muscles to have a 
 jelly-like consistency. They injure the cattle in regard to 
 growth and to milk conditions. The annoyance of the flies 
 
 r .-A ^ 
 
 b. 
 
 / \ 
 
 
 
 i 
 
 
 
 ' 1 
 
 
 : 
 
 
 WfJ 
 
 ' )It 
 
 i"4$'$f 
 
 Fig. 217. — Hypoderma lineata: a, eggs attached to hair; b, c, d, dorsal, 
 ventral, and lateral view of egg; e, embryonic or first larva, as seen in egg; 
 /, fir, mouth parts of same enlarged; h, anal segments of same'still more 
 enlarged. (From Insect Life.) 
 
 when they deposit eggs and also the injury caused by their 
 presence in the back of the cattle is in England estimated 
 at about S5.00 a head. Eggs are attached to the hairs, and 
 the larvae, according to Curtice, pass into the mouth and 
 through the esophagus and through its walls into the adja- 
 cent tissue and migrate by slow degrees to the dorsal portion 
 of the body, finally reaching the subcutaneous tissue along 
 
FAMILY OESTRIDyE 
 
 273 
 
 the backbone, about six or eight inches from it and between 
 the shoulders and the hips. The time of the appearance 
 in that location and the time when the larvae are taken into 
 
 Fig. 218. 
 
 -Hypoderma lineata: ovipositor of female: a, from side; b, 
 tip, from below — enlarged. (From Insect Life.) 
 
 
 h 
 
 
 I 
 
 
 ''^ c 
 
 \ ] ' 
 
 
 a 
 
 d 
 
 Fig. 219. — Hypoderma lineata: second stage of larva from esophagus: 
 a, larva; h, enlargement of cephalic segments, end view; c, mouth parts; 
 d, enlarged end view of anal segment, showing spiracles and spines. (From 
 Insect Life.) 
 18 
 
274 
 
 ORDER DIRTERA 
 
 the moiitli are separated by (juite a period. Curtiee claims 
 to have found hirvie at all points between these two positions. 
 This cannot be purely accidental. More recently an Irish 
 investigator has reached the conclusion that the larvae bore 
 into the skin and migrate to the wall of the es()})hagus from 
 which point they travel to the position under the skin of the 
 back. The adults emerge in early summer, in Texas as 
 
 Fig. 220. — Hypoderma lineata: a, second stage of larva from back; 6 
 and c, enlargement of extremities; d, ventral view of third stage with 
 details of extremities at e and /; g, dorsal view of mature larva wnth enlarge- 
 ments of anal spiracles at h; i, the same, lateral view. Natural size indi- 
 cated by side lines. (From Insect Life.) 
 
 early as May, in northern States May or June. The larvae 
 are pretty well grown by February, and by early March they 
 have practically reached maturity and the grubs issue 
 during March and early April, drop into the ground and 
 pupate and remain in this stage for five, six,, or seven weeks, 
 and the adults come on from INIay to early June or the first 
 of July. 
 The European species which has now been studied with 
 
FAMILY T AC HI N I DM 275 
 
 special reference to its mode of introduction is believed to 
 follow the same method, but Miss Ormerod persisted in the 
 belief that the eggs were deposited on the back and that the 
 larvae bored through the skin, and claims to have seen chan- 
 nels through the skin through which the larvse travelled. It 
 is not likely that there would be this difference in the two 
 species. This species causes a great deal of loss in the old 
 world. The one method available for controlling either of 
 these species is the destruction of larvse during the late 
 winter and early spring when they are conspicuous along 
 the back, and the method of extermination of the species 
 would be to have all animals examined and all the grubs found 
 destroyed. This is feasible theoretically, but impossible 
 practically. They do not migrate far, and any stock owner 
 can by close attention secure a large measure of immunity 
 for his own herd. Cooperation would secure a more extended 
 extermination. 
 
 Siieep Bot Fly {Oestrus ovis). — The sheep bot fly illustrates 
 another method of development. It deposits eggs or newly 
 hatched larvae in the nostrils of sheep and these work their 
 way up the passages. This entrance occurs during summer 
 time and the development of the larvae goes on through fall 
 and the larvae work their way back in spring and pupate in 
 the ground and the flies issue in midsummer. They cause 
 the greatest irritation and most serious symptoms occur 
 during the time the larvae are w^orking themselves back. 
 The sheep sneeze, etc., and sometimes show a dizziness or 
 stagger. They may be cut out of the frontal sinuses but the 
 cost of the operation is too great for general use. Preven- 
 tion consists in avoiding the deposition of eggs in the nos- 
 trils. Applying tar to the noses is one method, and another 
 method is by furnishing plowed places or dusty places so that 
 the sheep can bury their noses when the flies try to deposit 
 eggs, or by giving the sheep a shed, as the flies are active 
 in the sun and not in the shade. 
 
 Family Tachinidse. — The family Tachinidce has a very 
 important economic position on account of the large number 
 of species that are parasitic upon destructive insects. The 
 
276 
 
 ORDER DIPTERA 
 
 adults appear much like the house flies or the stable fly but 
 have usually numerous prominent bristles and spines, the 
 bristles (arista) of the antennae lack the fine hairs which are 
 characteristic of most of the Miiscidoe. 
 
 These insects show some very striking adaptations in their 
 parasitic life, some of the species depositing their eggs 
 directly upon the bodies of the caterpillars which are to be 
 the hosts of the larvae. The larvse on hatching bore at once 
 into the caterpillar and develop within its tissues. In cer- 
 
 ^--=^ 
 
 Fig. 221. — Euphorocera claripennis, a parasite of the alfalfa caterpillar: 
 adult and enlarged antenna of same; puparium — enlarged. (From Howard, 
 Bur. Ent., U. S. Dept. Ag.) 
 
 tain species the eggs are laid upon the leaves and depend 
 for their entrance to a host insect upon th^ leaf being eaten 
 by some herbivorous form and in this case it would seem as 
 if there would be some chance of the eggs being crushed or 
 the larvse being destroyed in the process of swallowing. In 
 one rather remarkable form the eggs are evidently deposited 
 within the burrows of wasps which are stored Avith spiders. 
 The TachinidoB follow the wasps as they drag their victims 
 to the burrow and when the wasp enters they no doubt 
 
FAMILY MUSCID^E 
 
 277 
 
 deposit their eggs upon the spider, the larva feeding upon 
 the food intended for the wasp larva or possibly upon the 
 wasp larva itself. 
 
 The typical Muscid flies (Muscidce), house fly, blow fly 
 screw-worm fly, all live in organic matter in a state of decay, 
 and all of them show very rapid rate of development, the 
 larvie acquiring their growth in a few days' time, though 
 longer time is usually passed in the pupa stage. The adults 
 may live for a long time. House flies, for example, conceal 
 themselves about houses and survive the winter, possibly 
 also as pupse, and deposit eggs which start the summer 
 
 Fig. 222. — Common house fly (Musca domestica): puparium at left; 
 adult next; larva and enlarged parts at right. All enlarged. (After Howard, 
 Div. Ent., U. S. Dept. Ag.) 
 
 generations which follow each other with a great deal of 
 rapidity. Twelve to fifteen days is all that is required for 
 the complete cycle of many of the species. They are scaven- 
 gers and in this may be looked upon as beneficial. They 
 present also certain dangerous aspects as carriers of disease, 
 especially typhoid, and deserve all the opposition they are 
 receiving. 
 
 The screw-worm fly deposits eggs occasionally in the 
 nostrils of individuals, and in the case of wounds of animals 
 the larvse work into the living tissue. It causes losses in 
 cattle industry in the South. 
 
27S ORDER DIPTERA 
 
 The house fly (Miisra dottiest lea) is i)erhaps the most 
 universal, and oeeurs wherever civilization extends, and 
 presents an important feature in its possibilities of carrying 
 disease germs. One of the first cases establishing this con- 
 
 
 '%:^') 
 
 '^^n 
 
 k 
 
 '1 
 
 ^ 
 ^ 
 
 CL 
 
 
 Fig. 223. — The common house fly: a, full-grown larva; 6, one of its 
 anterior spiracles; c, antenna; rf, hind end of body showing anal spiracles; 
 e, side view of head; /. head from above; q, head of young larva; /?, eggs. 
 All enlarged. (From Howard, Div. Ent , U. S, Dept. Ag.) 
 
 nection was that determined during the Spanish- American 
 war, where the source of the typhoid was traced to house flies. 
 It is known to serve as a carrier for tuberculosis, dysentery 
 and other diseases. Flies breed in filth, especially horse 
 manure, the eggs requiring a few hours to hatch, the mag- 
 
FAMILY MUSCID^ 279 
 
 gots from four to six days to grow, and pupation six to eight 
 days, so there may be many generations in a summer. Pro- 
 tection may be readily gained by community efi'ort. Their 
 flight is sufficiently restricted to make individual effort on 
 a farm well worth while, even if some nearby farms are neg- 
 lected. 
 
 
 
 # -b<^ 
 
 -*\ 
 
 
 
 
 1 
 
 s^ <^ 
 
 m 
 
 J 
 
 
 iH 
 
 f 
 
 v.: 
 
 <3L 
 
 
 -5 
 
 Fig. 224. — The common house fly: a, pupa removed from puparium; 
 b, hind end of body of larva in second stage; c, anal spiracles of larva in 
 fiist stage. All enlarged. (From Howard, Div. Ent., U. S. Dept. Ag.) 
 
 Horn Fly (Hceviatohia serrata Rob.-Desv.). — In the intro- 
 duction and rapid spread of this insect we have an excellent 
 illustration of the importance of giving attention to the 
 injurious insects of other countries and of taking all possible 
 means to prevent their importation. 
 
 The species in hand has been a common insect in Em-ope, 
 and with other members of the same genus recognized as a 
 troublesome insect, though apparently no careful study of its 
 life history has been made there. 
 
280 ORDER DIPTERA 
 
 It was first noticed as troublesome to cattle in this country 
 in 1887, and while we cannot say with certainty just when 
 it was introduced, we may be pretty sure that it was during 
 the year 1886, or at most not earlier than 1885. It is even 
 possible that it may have been brought over in the spring of 
 1887, as its powers of reproduction are such that a few weeks 
 would suffice to make it a conspicuous pest 'in a limited 
 area. 
 
 Within two years from the time it was first recognized in 
 serious numbers it had become so numerous and had spread 
 over so large a region that it w^as made the subject of a 
 very careful and successful study by Messrs. Howard and 
 Marlatt of the Division of Entomology. The results of 
 these investigations were published in Insect Life (vol. ii, p. 
 93) and in the Annual Report of the Commissioner of Agri- 
 culture for 1889. 
 
 As to its introduction and spread in America, all accounts 
 agree in placing the first serious occurrence of this insect in 
 the vicinity of Philadelphia, and it appears probable that 
 it was at that port that the flies first landed. 
 
 From there as a centre it spread in all directions, though 
 at first mainly southward, and by 1889 it had covered most 
 of the State of New Jersey, portions of eastern Pennsylvania, 
 a considerable area in Maryland, and also a portion of 
 northern Virginia. 
 
 In 1891 it had been reported from New York, Ohio, Ken- 
 tucky, Georgia, Florida, and Mississippi, and in 1892 from 
 Connecticut, Massachusetts, Canada, Michigan, Indiana, 
 Iowa, Louisiana, and Texas. 
 
 The adults of the horn fly are about half as large as the 
 common house fly and very much like it in shape and color. 
 The accompanying figures will serve to distinguish it. The 
 larval stages are passed in from four to six days. 
 
 The pupa stage may last from five to eight or ten days, so 
 that the full time from egg deposition varies from ten to 
 seventeen day s, estimated for the average as about two weeks. 
 As the flies doubtless begin laying soon after issuing from 
 the pupa stage, there is room for a number of generations 
 
FAMILY MUSCIDjE 
 
 281 
 
 during even a northern summer, probably from six to eight 
 being common. 
 
 For the destruction of the larvae, which is probably the 
 most effective way of preventing damage, two principles 
 have been established. The first involves the killing of the 
 maggots by introduction of some destructive agent; the 
 other, the prevention of their maturing by the rapid drying 
 
 Fig. 225. — Horn fly (Hematobia serrata): a, egg; h, larva; c. puparium; 
 d, adult in biting position. All enlarged. (From Riley and Howard.) 
 
 of the mass of dung which supplies their food. The use of 
 lime, as originally suggested in bisect Life, is a very effective 
 plan, and where not prohibited by expense, should be generally 
 adopted. Prof. Smith's suggestion to spread out the drop- 
 pings of manure so that they may dry rapidly is applicable 
 during dry weather and in some localities is accomplished by 
 drawing brush across the fields, a method which must 
 
282 
 
 ORDER DIPTERA 
 
 necessarily fail to })e c'()in])lete in its ojx'ration, bnt much less 
 expensive than the use of a shovel by hand. 
 
 The Stable Fly {Stovioxys cakitrans, Linn.). — The stable 
 fly is a well-known species which is widely distributed and a 
 familiar pest in many countries. Its bite is severe and it 
 causes a great amount of annoyance to cattle, horses and 
 other domestic animals, and is frequently very troublesome 
 to people working in places where it abounds. It is not 
 confined to stables or to the quarters of domestic animals, 
 but occurs frequently in shady places, groves and in dwell- 
 
 FiG. 226. — Stomoxys calcitrans: adult, larva, puparium, and details — all 
 enlarged. (From Howard, Div. Ent., U. S. Dept. Ag.) 
 
 ings, especially in cloudy weather, and puts the occupants 
 to great inconvenience. Its bite is not poisonous, and aside 
 from the pain given and the possibility of it disseminating 
 disease, it is less injurious than some other members of the 
 group. When abundant, however, this annoyance may be 
 very great, and they all deserve attention. Indeed, it is 
 especially charged against this species that they have been 
 the means of transmitting glanders from diseased to healthy 
 horses, and anthrax among cattle, a charge which appears 
 very reasonable from the fact that it inflicts a deep bite and 
 
FAMILY MUSCIDM 
 
 283 
 
 does not gorge itself at a single animal, but may fly from 
 one to another in securing a meal. 
 
 In late years it has come into especial prominence as a 
 a carrier of disease. It was at one time thought to be the 
 carrier of infantile paralysis but this relation has not been 
 substantiated. 
 
 Fig. 227.— Muscina stabulans: a, larva; b, head below; c, head, side 
 view; d, thoracic spiracle; e, stigmatic plate; /, female; g, head of female; 
 h, mouth parts; i, antenna. All enlarged, d, e, h, i, greatly enlarged. (Bur. 
 Ent., U. S. Dept. Ag.) 
 
 Tsetse Flies. — The tsetse flies have been notorious for a 
 long period as extremely serious pests in parts of Africa 
 and were described by early explorers because of heavy loss 
 to domestic and wild animals. In recent years these have 
 been connected with the transmission of certain kinds of 
 diseases, and are now looked upon as having a most impor- 
 tant bearing from the medical standpoint. 
 
 The species longest known, Glossina morsitans, has been 
 especially connected with loss among cattle, and horses. 
 Glossina palpalis which has been determined as the cause 
 
284 
 
 ORDER DIPTERA 
 
 Fig. 228. — Glossina palpalis ( X 3f), the carrier of the trypanosome of 
 sleeping sickness. (Bruce.) 
 
 Fig. 229. — Phormia terroRnovoe — enlarged. (Howard, Div. Ent., U. S. 
 Dept. Ag.) 
 
FAMILY MUSCID^ 285 
 
 of sleeping sickness in man has received perhaps the greater 
 attention in recent years. 
 
 It can easily be seen that the introduction of either of 
 these species into this country or even into South America, 
 with the opportunity for further distribution would be a 
 most serious menace, as there would be every possibility of 
 the introduction of the diseases which are associated with it. 
 These are perhaps examples of insects which deserve most 
 careful attention from the stand-point of possible exclusion, 
 and every effort made to learn their habits in detail and to 
 
 Fig. 230. — Lucilia coesar — enlarged. (Howard, Div. Ent., U. S. Dept. Ag.) 
 
 avoid such means of transportation as might possibly serve 
 to transfer them to this country. It is reported that such 
 an introduction has occurred in Australia. 
 
 Blue-bottle Fly {Lucilia ccesar). — The blue-bottle fly is 
 another species which is very abundant and almost uni- 
 versally distributed. Its attacks are made upon any avail- 
 able fleshy material such as carcasses of dead animals, fish, 
 and so on. The female deposits eggs on living animals that 
 have bruises or wounds or attractive points for deposition. 
 Sheep are especially subject to attacks of this sort. The 
 maggots of the flies do not limit themselves to the external 
 
280 
 
 ORDER DIPTERA 
 
 parts but ])urr()w into the flesh and may perhaps cause very 
 serious injury. 
 
 The meat fly or blow fly is another species that falls in 
 the same group with regard to its habits, and against which 
 it is important to protect domestic animals. 
 
 Flesh Flies {Sarcophagidcp). — Flesh flies are quite familiar 
 objects around houses, especially if there is any exposure of 
 
 Fig. 231. — The green-bottle fly: a, egg masses in cow dung; 6, hatched 
 egg; c, a portion of the egg surface seen under the microscope; d, unhatched 
 egg; e, larva. All enlarged except a. (From Ann. Kept., U. S. Dept. Ag., 
 1890.) 
 
 fresh meats to attract them. The eggs are laid on meat by 
 preference and hatching occurs within a very short time, in 
 fact in some species it is stated that larv^ are extruded from 
 the adult. Aside from their deposition upon meats, how- 
 ever, there is often a deposition upon fresh wounds or abra- 
 sions so that the larvae may make a serious attack upon 
 domestic animals or even human beings, if there is an oppor- 
 tunity for the attack. As a protection against this kind of 
 
FLESH FLIES 
 
 287 
 
 injury it is important that all bruises or scratches should 
 be treated promptly so that domestic animals will not serve 
 as an attraction for the species. 
 
 Fig. 232. — Homalomyia brevis: female at left; male at centre, with 
 antenna enlarged; larva at right. All enlarged. (Aftei Howard, Bur. Ent., 
 U. S. Dept. Ag.) 
 
 Fig. 233. — Apple maggot (Rhagoletis potnonella) : a, adult; b, larva or 
 maggot; c, funnel of cephalic spiracle; d, puparium; e, portion of apple 
 showing injury by maggots; a, b, and d, enlarged; c, still more enlarged; 
 e, reduced. (After Quaintance.) 
 
 In the genus Brosoyhila are a number of species, the 
 pomace flies" which feed principally upon decaying fruits. 
 
288 ORDER DIPTERA 
 
 They are perhaps of sHght economic importance as they do not 
 attack growing plants, but on account of the great ease with 
 which they may be bred in captivity they have been the 
 basis of some most important investigations concerning the 
 transmission of hereditary, characters. 
 
 Another species is one that occurs as a pest in apples and 
 is known as the apple maggot {Rhagoletis pomonella) , which 
 diflFers in its method of work from the codling moth larvae 
 in that the larvae work near the skin and make tunnels 
 through the apple. It punctures the skin and deposits eggs 
 inside. This goes on during the summer and the larvae 
 mature in autumn with the maturing of the fruit. They 
 hibernate as pupae. This species occurs now and then in 
 Ohio, but is not so universally common as the apple worm. 
 It is more distinctly a northern species, sometimes a serious 
 pest in New England and parts of the States and Canada 
 bordering on the Great Lakes. 
 
 Family Hippoboscidae. — The family Hippoboscidce includes 
 sheep ticks, and forest flies. They have the wing structure 
 of the Diptera, suctorial mouth parts, but a very remarkable 
 method of reproduction. Instead of extruding eggs, they are 
 retained in the oviducts and developed through the larval 
 stage, being nourished by nutritive fluids. They are not 
 extruded until they are ready to pass into the pupa stage. 
 They take no nutriment as pupae after leaving the oviducts. 
 There is no food taken until as adults. There is an adapta- 
 tion for the parasitic habit. This is a different sort of adapta- 
 tion than is found in any other group of Diptera except the 
 succeeding group. They are different from any other group 
 of animals. 
 
 Sheep Tick (M.elophagus oviniis, Linn.). — The sheep tick is 
 a common pest of sheep. It differs from the most of the 
 other members of the family in never possessing wings. The 
 head is small and sunken into the prothorax. The middle 
 portion of the prothorax is rather slender, contrasting with 
 the development of this region in the winged forms. 
 
 It is of a reddish or gray-brown color, about one-fourth of 
 an inch long, and easily detected when present in any num- 
 
ORDER SIPHONAPTERA 289 
 
 ber on sheep. They never migrate from the original host 
 except it be to attach to another animal of the same species, 
 and probably the principal movement is that which occurs 
 after sheep are sheared, when the ticks tend to migrate to 
 lambs. On the sheep, if abundant, they may cause con- 
 siderable damage, indicated by lack of growth or poor 
 condition, and when massing upon lambs they may cause 
 great damage, resulting in the death of the victims if not 
 promptly relieved. 
 
 They are distributed over the world generally where 
 sheep are kept, and are too well known by sheep breeders 
 to make it necessary to emphasize the injury they may 
 cause. All breeds of sheep seem alike subject to attack, 
 but I know of no record of their occurrence upon other 
 animals. 
 
 While the ticks may be greatly lessened in number by the 
 vigorous use of pyrethrum — a most available remedy during 
 winter — the most practical plan to adopt, and one which if 
 thoroughly followed will make all others unnecessary, is to 
 dip the sheep each year after shearing. 
 
 A flock once freed from the pests will not be again infested 
 except by the introduction of infested animals: hence care 
 should be taken in making additions to the flock to free the 
 newcomers from parasites. It is also well to keep the sheep 
 for a few days after dipping in a different inclosure from 
 that occupied before, to avoid possible infestation from any 
 stragglers that may have been caught on wool upon posts 
 or brush, and if the wool is charged with them when clipped, 
 it should be stored where the ticks could not easily return to 
 the sheep. The ticks cannot travel any distance inde- 
 pendently, and will soon die when removed from the sheep, 
 and proper care here will insure success. 
 
 Order SIPHONAPTERA. 
 
 Another order is the Siphonapfera, The fleas are wingless 
 or have the wings so aborted that they are practically wing- 
 less. Vestiges of wings may occur but are useless as organs 
 19 
 
290 
 
 ORDER SIPHONAPTERA 
 
 of locomotion. The adults have suctorial mouth parts and 
 puncture various kinds of animals, sucking the blood for a 
 food supply. The larvae are slender and live in refuse and 
 rubbish, litter of dog kennels, etc., and when mature change 
 to a very distinct pupa stage and then to adult flea. The 
 pupa stage is like the adult in shape but the legs, etc., are 
 encased in the rigid pupa case. The hindlegs are specially 
 
 , Fig. 234. — Cat and dog flea (Ctenocephalus canis): a, egg; b, larva in 
 cocoon; c, pupa; d, adult; e, mouth-parts of same from side; /, antenna; 
 g, labium from below; b, c, d, much enlarged; a, e, f, g, more enlarged. 
 (After Howard.) 
 
 developed and their mode of progression is by leaping. 
 They occur on different kinds of animals, as the dog and cat, 
 and there are species that occur in houses, on squirrels, 
 rats, mice, and various mammals. It is mainly on the 
 smaller species of mammals, and one species occurs on birds. 
 One species attacks poultry. It buries itself in the skin 
 something like a jigger, though not so extreme in the extent 
 to which it will burrow. 
 
CHAPTER X. 
 BEES AND WASPS. 
 
 Order HYMENOPTERA. 
 
 The Hymenoptera are in some respects the culmination 
 of the group of insects. They are speciahzed in several ways 
 but the species are all characterized by having the mouth 
 parts developed into both biting and sucking structures. 
 In some respects they seem more specialized than all other 
 orders and in some respects they seem less specialized than 
 the Diptera and Lepidoptera. As a matter of fact in the 
 evolution of the groups of insects there are several orders 
 that must be looked upon as having evolved along divergent 
 lines at the same time and none can be said to really outrank 
 the others. The Coleoptera, Diptera, Lepidoptera, and 
 Hymenoptera, all have a high degree of specialization. It 
 is better not to try to consider them as in the line of a series 
 of steps running up, but as parallel or divergent branches 
 from a general trunk, all of them extending to extreme 
 distances from the primitive stock. 
 
 The Hymenoptera have four wings, and these are provided 
 with rather few veins and pretty highly specialized in the 
 venation, and in a few groups the veins are practically 
 reduced to nothing. The mandibles are present for the most 
 part in the adult forms but are almost lost in some forms that 
 are fed by the adults in communal forms. They are both 
 mandibulate and haustellate. The larvse are usually footless, 
 fleshy, grub-like animals which depend on their food being 
 supplied for them in one way or another and are incapable 
 of moving about and securing their own food supply. This 
 represents a high degree of specialization and reaches its 
 
 (291) 
 
292 BEES AND WASPS 
 
 culmination in the community habit of ants and bees. In 
 no otlier group except the white ants is there such develop- 
 ment of the community habit. 
 
 The pupa stage is generally included in the nest or cells 
 formed for the larval stage, and the forms are seen to be 
 quite highly specialized when the cocoon is cut open. The 
 larvae moult but the moults are not so conspicuous as in 
 exposed forms. The group exhibits quite a variety of 
 habit, some leaf -eating forms, some wood-boring forms, 
 some that develop in galls, many that are parasitic inter- 
 nally on other insects, and many store food in their nests, 
 such as spiders, caterpillars, etc. These are sometimes 
 stored in the ground, sometimes in mud cells, sometimes in 
 channels in the wood, sometimes in paper cells. 
 
 There are two large divisions, the Phytophaga, leaf-eating 
 or plant-feeding free caterpillar-like forms, and the Aculeata 
 which represent the other forms of the group, the larvae of 
 which are dependent on a food supply provided by the adult. 
 The adults of this group have a sting. 
 
 The group Tenthredinidos is a large family of leaf-eating 
 and gall-making insects and the typical ones being the 
 willow saw fly and the gall-making willow forms. 
 
 The willow saw fly {Cimbex americana) is one of the largest 
 species that we have. The adult is steel blue, the wings 
 smoky. It is quite conspicuous and lays its eggs on the 
 leaves of the willow along the midrib and principal veins of 
 the leaf. The larvae hatch in a few days and grow during 
 the midsummer and are noticed as large yellow caterpillar- 
 like forms clinging to the twigs and leaves of willow par- 
 ticularly or sometimes also to elms and a few other kinds of 
 of trees. Some of the larvae have a prominent black dorsal 
 line. They coil themselves quite a little especially when 
 resting. While feeding the body is stretched out and they 
 cling by means of the prolegs of the abdomen as well as by 
 the thoracic legs. Prolegs are similar to those of the cater- 
 pillar. There are certain similarities with some of the very 
 generalized Lepidoptera and the prolegs might possibly be 
 taken to indicate some affinity. However, it is probably 
 
ORDER HYMENOPTERA 293 
 
 better to look upon it as an independent development of a 
 similar structure based on similar habit. The number of 
 prolegs varies from twelve to sixteen. There are twenty-two 
 legs altogether. The' saw fly larvse become fully grown by 
 the latter part of the summer and secrete themselves near 
 the surface of the ground, generally among dead leaves and 
 rubbish. They spin a quite strong silken cocoon with a 
 papery texture, somewhat more dense than is common for the 
 caterpillars of the silk-making moths. In this cocoon they 
 remain as larvse for quite a period. They finally pupate and 
 the adults issue in the spring and deposit eggs so as to 
 produce the summer generation of willow worms. They 
 become of economic importance where the shade trees they 
 feed upon are of importance — willow trees, elm, etc. They 
 are parasitized and the cocoons are eaten by mice and so 
 kept down generally to a moderate number and are not 
 usually very destructive. 
 
 The pear slug {Eriocampoides limacina) occurs quite 
 commonly in orchards and attacks not only the pear, from 
 which it dervies its name, but also apple and other orchard 
 trees. The larva has a strict resemblance to the mollusks 
 called slugs, as the body is covered with a dense slimy secre- 
 tion which hides the segmentation and external features of 
 the body. They feed upon the surface of the leaves, just 
 leaving ribs and veins. The trees attacked often have the 
 appearance of being scorched by fire. 
 
 They are best treated by the application of arsenical solu- 
 tions, applied as soon as their work appears. 
 
 The American rose slug (Endelomyia rosce) is frequently 
 troublesome in its attacks on the leaves of rose bushes which 
 are stripped or skeletonized so that the bushes are rendered 
 quite unsightly. 
 
 Arsenical solutions can be used, or if these are not desired, 
 hellebore may be used for their control. Other species 
 affect gooseberry, strawberry and other such crops. Many 
 instances being of considerable importance. 
 
 The Uroceridoe are wood- or stem-boring species and 
 more specialized than most of the preceding family. 
 
294 
 
 BEES AND ll'yl,SP.S' 
 
 One form is particularly interesting, Tremex cohimha, or 
 horn tail or pigeon tremex. It has a rather peculiar shape 
 both in the larval and adult stages. The adult is an inch 
 or more in length and with a prominent ovipositor which 
 extends back about one-half inch from the back of the 
 abdomen; both larvje and insects are cylindrical, the result 
 of the boring habit. These adults appear in summer and 
 deposit eggs on the bark of different kinds of forest trees — 
 sycamore, maple, and others. The larviie burrow in, form- 
 
 FiG. 235. — Pear slug: a, adult saw fly, female; h, larva with slime 
 removed; c, same in normal state; d, leaves with larvae, natural size; 
 a, b, c, much enlarged. (From Marlatt, Div. Ent., U. S. Dept. Ag.) 
 
 ing tunnels through the heart wood pretty well down into 
 the tree. Sometimes the trees are extensively perforated. 
 Boring continues in through the tissue of the wood till they 
 get their maturity and then they burrow out through the 
 bark. Pupae are formed in the burrow near to the surface 
 of the tree and the adult works its way out from the cocoon 
 after the pupa is split open. Occasionally the adults will 
 be found with the ovipositor fast in the bark of the tree 
 or in the wood. They burrow in to deposit eggs and seem 
 
ORDER HYMENOPTERA 295 
 
 unable to withdraw the ovipositor. Presumably they 
 deposit a single egg in each perforation. There are two 
 common parasitic species, Thalessa atrata and limator, 
 which are the natural check upon the multiplication of this 
 form and which ordinarily keep its numbers down to narrow 
 limits. Without this check the species would probably mul- 
 tiply .to a great extent. The parasites are representatives 
 of another family, IchnewnonidoB. They are rather slender- 
 bodied and with extremely long ovipositors. In Thalessa 
 atrata they are four or five inches long. These are driven into 
 the burrows of the tremex and the eggs are deposited in the 
 burrow and presumably at some point close to the tremex 
 larva. The larva of the Thalessa is said to attack the tremex 
 larva externally and not to be internally parasitic— a little 
 variation from the general habit of parasitism for the family. 
 Cynipidse.— The Cynipidoe are in one sense a vegetable- 
 feeding group, though some are hosts or guests of gall-makers. 
 The primary feature is that they make galls and the larvse 
 develop within these galls. Galls are not a normal plant 
 product, nor a product of the insect alone, but a combma- 
 tion product of the insect and the plant. A stimulus given 
 to the plant cells results in a definite specific form of growth 
 which is just as specific as the form of the leaf or the fruit 
 of the plant on which it is formed. Species can be deter- 
 mined accurately from the form and structure of the gall. 
 The most familiar of these galls are the oak apples. These 
 are rich in tannic acid which gives the gall a decided flavor. 
 A globular structure is built out by a great growth of plant 
 cells. The gall grows and develops more rapidly than the 
 larva. The larva gets its growth by eating the cells which 
 are close to it and all the rest of the structure is apparently 
 developed purely as a protective device for the larva. 
 The greatest number of species occur on oaks, some on 
 roses, etc. There are dozens of different kinds on oaks and 
 many different species on a single species of oak and some 
 restricted to one certain species of oak alone. 
 
 Parasitica includes several f amihes : IchneumonidcB, a large 
 group ; Braconidoe; Chalcididw, a large group ; and Proctotrupid(B. 
 
296 BEES AND WASPS 
 
 All of these are distinctly parasitic in habit. BraconidcB 
 and IchneumonidcB are the more generalized kinds of para- 
 sites and parasitize such forms as the caterpillars of the 
 Lepidoptera in immense numbers. They constitute a very 
 important check upon a number of very important species. 
 It is hard to do much in the way of encouragement of them, 
 though they may be transported from one country to 
 another. One subfamily is pretty commonly parasitic on 
 plant lice. 
 
 ChalcididcB form a specialized group with much reduced 
 venation for the wings and the Proctotrupidce are minute 
 and largely egg parasites. 
 
 Family Ichneumonidse. — The Ichneumon flies include 
 many of the larger species of parasitic Hymenoptera and a 
 number of species which have important economic bearing 
 on the abundance of destructive species. Good examples are 
 to be noted in the species of Thalessa which parasitizes the 
 pigeon tremex and in species of Ophion which attack a num- 
 ber of different kinds of caterpillars. The species of Pimpla 
 are also conspicuous members of the group and their attacks 
 are made especially upon injurious species of moths, so that 
 they are to be counted distinctly serviceable. 
 
 Pimpla conquisitor is one of the parasites of the tent cater- 
 pillar and it is possibly due to this species that the tent 
 caterpillar is less destructive than it otherwise might be. In 
 this species the parasite lays its eggs in the cocoon of the 
 host and its larva develops within the pupa, so that it 
 serves to prevent the development of the adult and the 
 deposition of the eggs which would follow. 
 
 Family Braconidse. — The family Braconidoe is quite similar 
 to the preceding but the species are on the average smaller 
 and many of the species parasitize the minuter kinds of 
 insects such as plant lice. A quite common species is Apan- 
 teles glomeratus which is a parasite of the common cabbage 
 worm and which no doubt serves as a quite important factor 
 in assisting to keep this pest in check. 
 
 Perhaps one of the most important species is the little 
 Lysiphlehus tritici which is a very abundant parasite of 
 
ORDER HYMENOPTERA 
 
 297 
 
 Fig. 236. — Pimpla conquisitor, an important parasite of the tent cater- 
 pillar: a, larva, enlarged; b, head of same, still more enlarged; c, pupa; d, 
 adult female, enlarged; e, f, end of abdomen of adult male, still more 
 enlarged. (From Fourth Report, U. S. Ent. Con.) 
 
 Fig. 237. — Apanteles glomeratus: a, adult fly; 6, cocoon; c, flies escaping 
 from cocoons; a, b, highly magnified; c, natural size. (After Chittenden, 
 Div. Ent., U. S. Dept. Ag.) 
 
298 
 
 BEES AND WASPS 
 
 aj)hi(ls. It is a miiuito sj)ecies and its larva maintains its 
 entire growth witliin tlie body of an aphid, the entire eon- 
 
 FiG. 238. — Parasitized cabbage worm (Pontia rapce), showing cocoon 
 mass of Apanteles glomeratus below. (From Chittenden, Div. Ent., U. S. 
 Dept. Ag.) 
 
 Fig. 239. — Lysiphlebus trilici, principal parasite of the spring grain aphis: 
 adult female and antenna of male, greatly enlarged. (Webster, Div. Ent., 
 U. S. Dept. Ag.) 
 
ORDER HYMENOPTERA 
 
 299 
 
 tents of which are not equal to a drop of water. However, 
 the parasite may feed upon the aphid during some httle 
 time and is supplied with food from the efforts of the aphid 
 
 Fig. 240. — Wingless female of "green bug" containing larva of the 
 parasite Lysiphlebus tritici. Much enlarged. (Webster, Div. Ent., U. S. 
 Dept. Ag.) 
 
 sucking nutriment from the plant. This species is consid- 
 ered one of the principal agents in control of the spring grain 
 aphis or the "green bug" which during recent years has 
 
 Fig. 241. — Lysiphlebus depositing its eggs in the body of a grain aphis. 
 Much enlarged. (Webster, Div. Ent., U. S. Dept. Ag.) 
 
 caused extensive injury to the wheat crop in the south- 
 western part of the country. Its attack seems to be dis- 
 tributed, however, over a number of species and it is therefore 
 
300 
 
 BEES AND WASPS 
 
 able to maintain itself even in the absence of any one species 
 of plant louse. 
 
 Fig. 242. — Pteromalus puparum: female at left; male at right — highly 
 magnified. (Chittenden, Div, Ent., U. S. Dept. Ag.) 
 
 Fig. 243. — Chalcis ovata, a parasite of the alfalfa caterpillar: a, pupa; 
 h, parasitized pupa of tussock moth {Hemerocampa leuco stigma) : c, adult; 
 d, same in profile; e, pupal exuvium. Enlarged. (From Howard.) 
 
 Family Chalcididae. — ^The family Chalcididoe, one of the 
 groups which includes extremely minute insect forms which 
 parasitize insects, such as the plant lice, scale insects, and 
 
ORDER HYMENOPTERA 301 
 
 many other forms. They have broad heads, rather thick 
 jaws and are quite generally of brilliant metallic colors. A 
 distinctive character is found in the reduction in the veins 
 in the wings so that only the costal vein borders the front 
 margin of the wing and is so developed as to be rigid. In 
 larger insects a great number of these parasites may develop 
 in a single individual. In the smaller species usually a 
 single parasite is found in the host. They are especially 
 
 Fig. 244.— /sosoma tritici: adult of the joint worm— much enlarged. 
 Howard, Div. Ent., U. S. Dept. Ag.) 
 
 efi'ective in the destruction of scale insects, and some of the 
 species are parasitic in the eggs of other insects. In some 
 cases they become secondary or tertiary parasites in which 
 case their value is changed. 
 
 Pteromalus puparum, one of the parasites of the cabbage 
 worm, is apparently distributed well over the area occupied 
 by this species and its attacks upon the host form serve as 
 one of the quite constant checks upon the abundance of that 
 species. The parasitized pupse usually show a different 
 
302 
 
 BEES AND WASPS 
 
 color, and if observed these may be allowed to remain in 
 the fields with the expectation of the ])arasite serving a 
 good purpose for a later generation. If possible it is well 
 to assist them somewhat by putting the pupae under screens 
 which will permit the escape of the parasites, without 
 allowing the escape of butterflies which might issue from 
 healthy pupae. 
 
 While most of these species are parasitic, there are a few 
 which are plant feeders, and notable among these is the 
 
 Fig. 245. — Bits of hardened straw remaining with the grain after 
 thrashing. (After Webster, Div. Ent., U. S. Dept. Ag.) 
 
 wheat joint worm {Isosoma tritici), which is the cause of a 
 great deal of damage to wheat in many parts of the country. 
 The presence of the joint worm is evidenced by the forma- 
 tion of woody places in the stem, within which the worm 
 is found and the effect of its injury is to cause the stems to 
 become weakened so that frequently the grain will be broken 
 down, especially if there are severe winds. The insects pupate 
 within the stems and remain in the pupal stage all winter. 
 This accounts for their frequently being found in chaft' or 
 
ORDER HYMENOPTERA 
 
 303 
 
 straw. Sometimes the hard pieces of straw are carried over 
 in the threshing and mixed with the grain. It is evident 
 
 Fig. 246. — Isosoma tritici: female ovipositing. (Photo by Ohio Exp. Sta.) 
 
 that burning of the stubble in the fall or early spring will 
 destroy the pupa in the fields and it is considered that the 
 use of straw and chaff in the bedding of stock or as fodder 
 
304 
 
 BEES AND WASPS 
 
 is an excellent plan to reduce the infestation. Of course 
 burning chaff or straw would accomplish the purpose, but 
 
 Fig. 247. — Isosoma tritici: adult male. (Photo by Ohio Exp. Sta 
 
 Fig. 248. — Isosoma tritici: larvae. (Photo by Ohio Exp. Sta.) 
 
 this is not deemed necessary if the straw passes through the 
 barnyard, as most of the pupae are killed by this treatment. 
 
ORDER HYMENOPTERA 305 
 
 The egg parasites (Prodotrupidce) are extremely small, most 
 of the species being parasitic in the eggs of insects. Eggs of 
 web worms are parasitized and the whole development of 
 the Proctotrupid is contained within the egg. One species 
 is described as one-nintieth of an inch in length, another one 
 one-himdred-and-fiftieth of an inch and the body very slender. 
 These serve a most important function in the destruction of 
 other insects, those that would otherwise hatch from the 
 eggs. When the parasites feed on the caterpillars the damage 
 is only partly checked, but when the parasite feeds on the 
 eggs the damage is all prevented. One of the important lines 
 of economic entomology is to study such forms and their 
 life histories with regard to other species, as primary para- 
 sites, secondary parasites, tertiary parasites, etc., since 
 their value depends on whether they directly control a pest 
 or whether as a secondary parasite they reduce the numbers 
 of a primary parasite which is useful. 
 
 Ants (Formicina) are one of the most interesting groups 
 of insects. They are sometimes given the rank of a superior 
 family, but the principal family is that called Formicidoe. 
 The name is associated with the secretion of formic acid. 
 The name of the group probably gave the name to the 
 chemical. The secretion is one of the characteristics of the 
 Hymenoptera. Ants present striking habits of family life; 
 the formation of different classes among the individuals 
 of a colony. This separation into classes is paralleled in 
 other groups, as the bee family and among wasps, and 
 expecially the termites. The result of community life is 
 that it presents certain relations in the community in the 
 way of division of labor. The primary forms are males 
 and females, and then a class which are not sexual but are 
 derived from a modification or suppression of the reproduc- 
 tive factor in one of the sexes. Occurring with this is the 
 reduction or complete absence of wings. These constitute 
 the so-called workers or soldiers of a colony. They have no 
 wings whatever. This feature reaches far back into the 
 ancestry of the group, or else shows parallel evolution. 
 Sexual individuals have wings primarily but in the case of 
 20 
 
306 BEES AND WASPS 
 
 tlie queens the wings are broken off or dropped off after the 
 flight associated with mating. Then the females are unable 
 to travel and remain fixed in a certain colony and furnish 
 off'spring for the colony. A group of ants is called a formi- 
 cary. It may vary in number of individuals from a few 
 hundreds to thousands. A single queen ant may survive 
 for a great number of years and the same colony may go on 
 for many years. The usual course of the life-cycle is for 
 winged females to issue from some colony and make their 
 flight that is connected with mating, and then to burrow 
 into the ground or select a suitable nest to place the eggs 
 and begin the formation of a new colony. The fertilized 
 queen is capable of producing workers and in some cases the 
 queen alone wdll start a colony. In some forms perhaps the 
 help of other ants is needed. With the starting of the 
 colony and the deposition of eggs a colony becomes more 
 populous. Differentiation has not gone quite so far in ant 
 colonies as in some others. The workers take care of the 
 eggs and the young and shift the young about, and if the 
 nest is disturbed they carry the pupse to a place of safety. 
 The pupae are, of course, helpless. The workers and soldiers 
 die off pretty rapidly. They survive through the w^orking 
 period and when they die are replaced by other workers. 
 The colony retains its individuality year after year. The 
 life of the colony is probably at least as long as the life of 
 the queen and probably continues longer than that. Other- 
 wise the colony w^ould have to terminate soon after the 
 death of the queen. The multiplication of colonies is pro- 
 vided for by the issuing of new queens from the colonies 
 and the ability of the ant to survive depends as much on 
 its ability to form new colonies as on new individuals. 
 There is just as much reproduction of colonies as of indi- 
 viduals. The cycle is probably for annual periods in each 
 season and the females are probably produced annually. 
 The food of the ants is primarily plant food. They collect 
 nectar and various substances of vegetable origin, and the 
 workers are responsible for the collecting and storing and 
 using of the food supply. Indirectly they get such supplies 
 
ORDER HYMENOPTERA 307 
 
 from the aphids. They store up grain in some instances, 
 and use this grain to some extent at least as a food 
 supply. 
 
 One of the species — the honey ants — collect honey and 
 store it in the stomachs of certain individuals of the colony. 
 The bodies of these individuals become very much distended 
 and the abdomen becomes large and spherical and these 
 keep the food for a part of the year. This ant occurs in the 
 plateau regions of Colorado, particularly in the Garden of 
 the Gods. The volume by McCook on these ants is an 
 especially interesting account of animal adaptation. Also 
 Lubbock's book on Ants, Bees and Wasps gives many 
 interesting experiments, but his observations indicated that 
 while there is an adaptation to complex conditions they are 
 not comparable to the activities of human beings. 
 
 There are many species — little red ants, those occurring 
 in gardens, and walks, the house ants, and the large car- 
 penter ants, which form nests in hollow logs. The queen is 
 quite a large insect and usually with wings entirely wanting. 
 Large red ants and large black ants construct hills for their 
 nests, sometimes three to six or eight inches high, and 
 perhaps twelve to eighteen inches across the top. This red 
 ant is a slave-making species, going out on forays and 
 capturing black ants which they force to carry on the labor 
 of the colony. Some species are said to have carried the 
 slave-making habit to such an extreme that they are unable 
 to get along without the slaves and even require slaves to 
 go out and capture new slaves. 
 
 Field Ants. — One of the important species is the little 
 field ant which is associated with the corn-root louse and 
 which has been named in connection with the discussion of 
 the aphid. This species is very widely distributed through- 
 out the United States and wherever corn is grown and the 
 corn-root louse is present it constitutes an important factor 
 in the abundance and destructiveness of the root louse. 
 
 The Argentine ant {Iridomyrmex humilis Mayr) is one of 
 the recently introduced pests and one which is liable to 
 become distributed to cover the Southern States and possibly 
 
308 BEES AND WASPS 
 
 to occupy at least the cotton-growing region if not a greater 
 extent of the country. 
 
 Tlie species is tliought to have been introcUiced from 
 Argentina and was first noticed in New Orleans where it 
 was reported as occurring in fair numbers in 1891. It is 
 now known throughout most of Louisiana and in eastern 
 Texas, and also occurs in California. Within the range of 
 its distribution it has become a very serious pest and its 
 further distribution will naturally be a matter of serious 
 consequence to other localities. Without assistance the 
 ant migrates slowly but with the opportunities afforded 
 by commerce its dispersal may be quite rapid. 
 
 As with the other ants there are males, females, and 
 neuters; the males and females being winged, the neuters 
 wingless but the females lose their wings after the mating 
 flight. 
 
 The size of the colonies varies from a few individuals to 
 many thousands and a number of queens may be present 
 in each colony. The nests are built in various places under- 
 ground, seldom occurring at any great depth. 
 
 This species is a most difficult one to control and experi- 
 ments with poisonous materials, repellants, etc., have met 
 with only partial success. 
 
 Wasps {Siihecina). — In this group we have a considerable 
 number of solitary forms of those which preserve the primi- 
 tive conditions of males and females without workers or 
 with large broods raised at one time in one nest. Mud, 
 paper, pith, etc., are used as building materials. The sand 
 wasp {Bemhecince) burrows into the sand for its nest. They 
 stock these nests with insects of difterent kinds such as May 
 flies. The larvae develop by feeding upon the bodies of these 
 stored insects. It is strange that they can keep a burrow 
 complete enough so that they can pass in and out a number 
 of times. They are very common here and are protected 
 to some extent by the coloration of the body. Their bur- 
 rows are constructed along through the summer and the 
 larvae develop during the summer and presumably all reach 
 the pupa stage before winter and live over as pupse, issuing 
 
ORDER HYMENOPTERA 
 
 309 
 
 the following season. The adults will be found flying around 
 all through the midsummer months. Perhaps they are a 
 
 Fig. 249. — The Argentine ant, adult forms: a, adult male; al, head of 
 male; a2, petiole of male; b, worker; bl, head of worker; b2, petiole of 
 worker; c, fertile queen; cl, head of queen; c2, petiole of queen. All 
 greatly enlarged. (After Newell.) 
 
310 BEES AND WASPS 
 
 little more abundant in the later part of July. They belong 
 to the Bcvihecidoe. One of the large members of the family 
 is called the "cicada killer" Sphecius speciosus. 
 
 Social wasps {Vcspidce) make large nests and large colon- 
 ies and show some degree of differentiation into classes or 
 castes of individuals in that there may be smaller indi- 
 viduals at the end of the season which live through the 
 winter. 
 
 The Hornet {Vespa maculata) builds up a large paper nest 
 which is made up of a series of combs with the aperture at 
 the lower part. This becomes very populous during the 
 latter part of summer. The survivors are adults that secrete 
 themselves under leaves and rubbish and start a fresh 
 colony the succeeding year. They do not live in the large 
 nest through the winter. This common species is social. 
 
 The yellow jacket {Vespa germanica) is also a social 
 species, its nests are found in hollow^ trees. 
 
 It is interesting to compare the materials used by these 
 species. They use wood or paper which is a pulp worked up 
 from the wood fiber and is to be compared with manufactured 
 paper in the tissue of which it is made and in the manner of 
 manipulation. 
 
 In the bees, Apidce, there is an elongation of the beak for 
 getting the nectar from the flowers and the more specialized 
 forms secrete wax for the formation of the cells. This is 
 worked up into a gum or built into cells for the rearing of 
 the larvae. There is a gradual culmination in the develop- 
 ment of community life in this family from the wild bees that 
 are practically solitary up to the bumble bee and honey bee. 
 The honey bee is probably the best-known because kept 
 under domestication. A bee colony consists of a queen, which 
 is a constant factor in the colony^a queenless colony can- 
 not survive any length of time — and drones or males which 
 occur during the summer. These are the normal-sexed indi- 
 viduals. Then we have the workers or neuter forms which 
 are undeveloped females and these carry on all of the com- 
 plex work of the colony, providing food, caring for the larvae 
 and for the rearing of new queens. 
 
ORDER HYMENOPTERA 311 
 
 The cycle as applied to the queen would involve three to 
 five years. They live that long and deposit millions of eggs 
 during that time. The drones live but a short period. The 
 workers live a few weeks or months through the summer 
 and in the more inactive parts of the year. The queens from 
 the egg stage to the adult stage occupy about sixteen days, 
 the workers twenty-one days, the drones twenty-four days. 
 There is a distinct difference in the eggs that produce workers 
 and drones. The worker eggs are fertilized and the drone 
 eggs are unfertilized. This is apparently controlled by 
 the queen and dependent upon the kind of cells in which 
 the eggs are laid. The exact method of control by the 
 queen is not fully understood. The size of the cells may have 
 some effect by the pressure on the abdomen. The accelera- 
 tion of the queen may be because the workers feed them with 
 a richer sort of food. They develop more rapidly and the 
 reproductive organs are fully developed. There is colony 
 reproduction as well as individual reproduction, that is, an 
 increase in the number of colonies. They die off from old 
 age, loss of queen, cold weather, etc., and if there were no 
 process for increasing the number of the colonies they 
 would be exterminated. This is provided for by swarming. 
 The queen and a large number of workers issue from the 
 colony and form a new colony. The old colony is provided 
 for by other young queens in the cells or else fertilized. 
 There is a loss of honey but no break in the life of the colony. 
 Bee-keeping is an important industry and there are many 
 books dealing with the subject. Among those of special 
 value are the following: 
 
 Cheshire, Honey Bee. Root, Bee-keeping. Langstroth, Hive and Honey 
 Bee. Snodgrass, Anatomy of the Bee. Benton, The Honey Bee. Cook, 
 Manual of Bee-keeping. Comstock, How to Keep Bees. PhiUips, Bee- 
 keeping. Pellett, Productive Bee-keeping. 
 
riTAPTKU XI. 
 PRIN( iri.KS OF ECONOMIC ENTOMOLOGY. 
 
 \ViiiLK it cannot be assumed that we liave at present a 
 C()ni])lete knowledi^e of tJiose underlying principles which 
 are to be recognized in the prevention or control of insect 
 ravages, enough has been done to make an attempt at a 
 brief statement of such i)rinci])les in order. Many of these 
 principles have been stated in greater or less detail in the 
 writings of diti'erent entomologists but no c()mi)rehensive 
 statement lias been attempted — especially since the marked 
 advances of the past quarter- century. Applied entomology 
 today is a totally different structure tlian that wliich 
 existed twenty or even ten years ago. In many respects it 
 is getting nearer to the fundamental laws of biology, and 
 there is a more general appreciation that its successful appli- 
 cation involves thorough acquaintance with biological prin- 
 ciples. In tlie broadest sense economic entomology involves 
 a recognition of the relation existing between insects and 
 other organisms, but finally, the relation they bear to the 
 human species. 
 
 RELATION OF INSECTS TO OTHER ORGANISMS. 
 
 Considering the great multiplicity of insect forms, their 
 world-wide distribution in almost every condition open to 
 the su])])ort of life, it is not strange they occupy a most 
 imi)ortjint relation to other organisms. This relation may be 
 serviceable or inimical, directly or indirectly from the 
 stand-point of any particular organism, and may indeed 
 differ totally at different times or under different conditions. 
 From the stand-point of any particular species it is detri- 
 (312) 
 
ECONOMIC ENTOMOLOGY 313 
 
 mental if the insect feeds upon the plant or animal or inter- 
 feres with its successful existence. It is beneficial, if it 
 contributes to its success by warding off other dangers or 
 assisting pollination or contributing in any way to its better 
 growth and development. 
 
 ECONOMIC ENTOMOLOGY. 
 
 Economic entomology is based upon the relation of 
 insects to mankind and all species that interfere with his 
 welfare are considered injurious, and those that may serve 
 him in any way are considered beneficial. The relation, 
 however, may become very complex. An insect that feeds 
 upon a cultivated crop, or destroys the products of a crop, 
 or injures a domestic animal, or worries man himself, or 
 menaces his health by inoculating him with disease, is 
 injurious from the human stand-point. While if it produces 
 a valuable material such as silk or honey, wax, dyes, etc., 
 or serves to destroy injurious species as predaceous and 
 parasitic forms, or feeds upon noxious plants, weeds, or dis- 
 poses of noxious substances, as the scavengers, it is directly 
 useful, and we term it beneficial. Many cases are very clearly 
 in one class or the other; many have little apparent impor- 
 tance one way or the other, and in many cases the relation 
 may change with circumstances. For example, a parasitic 
 insect preying on an injurious species is useful to us, but if 
 it destroys a useful insect it becomes injurious. A parasite 
 on a parasite, that is, a secondary parasite is detrimental if 
 the primary parasite attacks an injurious insect, and a 
 parasite upon this secondary parasite, that is, a tertiary 
 parasite would be useful, since its effect would be to check 
 the secondary and favor the primary parasite. Still further, 
 a quaternary parasite, and this is I believe as far as this 
 relation is known, would be injurious. The reverse in each 
 case would be true if the original host were useful. 
 
 We should not forget that these three terms refer strictly 
 to mankind, for in the broader biological sense each kind of 
 
ril 1 i'h'i.\cn'Li^:s of economic entomolocy 
 
 juiiinal is doing its host to ]HT])ctiint(' itsHf and nnilti])ly 
 its kind, and t'\rr}' intorl'crcnct' is from its stand-jxiint 
 injnrions. 
 
 FOOD HABITS. 
 
 It is very ovidtMit that ono of the first and most important 
 relations t'oncrrniniij an insect is to he fonnd in its food 
 liahits. 
 
 Insects, like other animals, may he considered i)rimarily 
 herhivorous. 'J'hat is, the most general ])lan of nutrition 
 for them ^\•onl(l he to feiMl ni)on fresh, growing leaves of 
 plants, with feeding iii)on fruits, seeds, hark, wood, roots, 
 decaying wood as adaptations, while the assumption of car- 
 nivorous hahits either as ])redaceous or parasitic species, or 
 to go further, sucking hlood of higher animals may he 
 considered adaptations in another direction. 
 
 It is on this hroad, general hasis that we may consider 
 herhivorous insects in the main injurious, and carnivorous 
 insects, es])ecially if })re(laceousan(l ])arasitic on other insects, 
 as heneiicial. 
 
 In this connection we may refer to the principle which 
 has been termed "unity of hahit" and treated hy Dr. B. D. 
 Walsh. This is in elVect that in any given group we may 
 expect to find similar hahits among all the s])ecies, and if for 
 any s])ecies the hahits are unknown, they may he expected 
 to follow those of the known species. To this law there may 
 he striking exce})tion, however, and along certain lines 
 peculiarities should he considered the rule and not the 
 exception. To find the most certain action of the law we 
 may, I think, say that in all particularly specialized groups 
 "unity of hahit" is practically general. In less specialized 
 grou])s variation is more frequent. For example, in the hark 
 heetles, ScoIi/ti(hv, we would he astonished to find a leaf- 
 eating larva, or in Aradidw a species that does not live under 
 hark is excejitional. In Lcpidojifcra, the larval diet is gener- 
 ally herhivorous and the two or three carnivorous species 
 notahly the exception. We safely assume that all plant 
 lice are ])lant feeders and treat them accordingly. The 
 
MEASURES FOR INSECT CONTROL 315 
 
 weevils are reckoned invariably as plant feeders, almost 
 entirely confined to fruit or seeds, while Carabidw, though 
 largely carnivorous, show too much variation in food and 
 too many herbivorous species to make it safe to draw con- 
 clusions without the study of each species. In the applica- 
 tion of this principle, therefore, it l)ecomes necessary to 
 consider the nature of the group as a whole, not merely 
 the habits of certain ones. 
 
 MEASURES FOR INSECT CONTROL. 
 
 There have been a great many difl'erent remedies and 
 plans of treatment for the control of injurious insects and it 
 would be impossible to discuss them all, even those which 
 have general application, in a short course. The attempt 
 will be to select some of the most universal and useful and 
 give them with such rules as to make it possible to apply 
 them without further instruction. 
 
 In general the methods of control for insects may be 
 separated into those which are direct and have in view the 
 destruction of the insect with some destructive agent or 
 mechanical application, and those methods that depend upon 
 some plan of cultivation or sequence of crops to prevent or 
 modify the insect attack. 
 
 Direct Methods. Insecticides. — Substances used in such 
 manner as to kill directly are termed insecticides, and insec- 
 ticides may be classed broadly into two large groups: (1) 
 those which are poisonous in character and depend for their 
 effect upon the insects swallowing them with their food and 
 (2) those which affect the insects by contact or penetration, 
 such as the oils and fumigants. 
 
 Of the poisonous materials some preparations that are 
 among the most important may be mentioned. 
 
 Paris Green. — Paris green is a bright green arsenical 
 powder which should contain at least 50 per cent, arsenious 
 oxide and not over 3.5 per cent, soluble arsenic. The for- 
 mulae for its use are as follows : 
 
 Paris green 5 ounces 
 
 Lump lime 1 pound 
 
 Water 50 gallons 
 
310 /'/;/.V(7/'/>/';n of fcoxomic estomolocy 
 
 For small (luautitics list*: 
 
 Paris urooii 1 hoa|)iii<; (easpooiifiil 
 
 Lxnnp lime 2 or 3 ounroy 
 
 Water 3 Rallons 
 
 For dry application tlio powdoRnl Paris uriHMi may Uv 
 mixed with llour or air-slaked lime and diistivl u|)on the 
 plants by enclosing- tlu^ ]>o\vder in a mnslin sack and shaking- 
 this over the plants it is desired to tn^it. 
 
 London purple is a hy-prodiict in the manufaetnre of 
 aniline dye and is an elVeetive poison hut somewhat less 
 certain in its elVeet and more likely to injure foliajj^e. It is 
 at ])resent not so eonnnon on the market as Paris i^nnMi. it 
 is, however, somewhat cheaper and when ])roperly diluted 
 is a desirable insecticide. 
 
 Arsenate of Lead. Arsenate of lead, available in two forms 
 — paste or as a white ])owder — may be secured on the market, 
 or the arsenate may be formed by chemical combination of 
 arsenic and lead. Formuliv for the use of this substance 
 are as follows: 
 
 Arsenate of load (p^ii^to) 3 to 10 pounds 
 
 Water 50 gallons 
 
 or 
 
 Arsenate of lead (powder) 1 to 4 pounds 
 
 Water 50 gallons 
 
 For small quantities use: 
 
 Arsenate of lead (paste) 1 teaspoonful 
 
 Water 1 gallon 
 
 If used as a spray this can be applied to a great variety of 
 plants for the destruction of leaf-eatins: insects, and since 
 it can be used at high strength without injury to foliage it 
 may be used for the most resistant kind of insects. Its killing 
 power is not equal to that of Paris green and consequently 
 somewhat stronger solutions must be used. 
 
 Like Paris green, it may be used in the (Iry fc^rm as dust 
 or with a ])owder gun. 
 
 Hellebore.- Hellebore is a white powder destructive to 
 insects but not poisonous to domestic animals or man, unless 
 
MEASURES FOIi INSECT CONTROL 'Ml 
 
 in large; (los(;s. It may he usee] as a spray or in a dry form 
 and is apj>lif;al)l(; to currant })ushes or other kinds of fruit, 
 for saw-fly larvae and other leaf-feeding insects where it is 
 undesirable to use arsenic. 
 
 Arsenical Bran Mash. — This is used as a })ait for cut worms 
 and otficr inscc-ts which endanger vegetation and which it is 
 desirable to kill before the; vegetation has been attack(;d. 
 Formula as follows: 
 
 Bran 25 pounda 
 
 Paris Krocn ^ pound 
 
 Cheap molasses 1 quart 
 
 Water, as needed to moisten. 
 
 For small quantities use: 
 
 Bran 1 quart 
 
 Paris green 1 teaspoorjful 
 
 Cheap molasses 1 tablespoonful 
 
 Water, as needed to moisten. 
 
 For grasshoppers the attractiveness of this bait is very 
 much increased by the addition of lime juir-c or r^rangf; or 
 lemon flavor. 
 
 Contact Insecticides. — Insecticides of this group def)end 
 upon immediate contact with the insects to be affected, 
 different kinds of sprays, direct applications and the use of 
 fumigants which are distributed to the insects to be reached. 
 
 Lime-sulphur wash is the most important of the insecti- 
 cides now in use against the scale insects, especially the 
 San Jose scale. The commercial lime-sulphur preparations 
 on the market generally may be secured at seed-stores 
 or from dealers in nursery or orchard supplies and depended 
 upon as containing the correct proportions and if used 
 according to directions should give very certain results. 
 These can be secured at reasonable prices and are often 
 preferable to the solutions of home preparation. How- 
 ever, directions for the preparation of the compound may be 
 of service and two formula; will be given, one for the conrrcn- 
 trated solution to be diluted when used and the other for 
 immediate use. 
 
318 PRINCIPLES OF ECONOMIC ENTOMOLOGY 
 
 Fig. 250. — Making lime-sulphur solution ( i'hoto. Ohio K\\>. St;i.j 
 
 Fig. 251. — Plant for making lime-sulphur solution in large quantities. 
 (Photo. Ohio Exp. Sta.) 
 
 Concentrated Lime-sulphur. 
 
 Lump lime 50 pounds 
 
 Sulphur 100 pounds 
 
 Water (hot) 70 gallons 
 
 Dilute as directed. 
 
MEASURES FOR INSECT CONTROL 319 
 
 For exact preparation the use of the hydrometer is desir- 
 able and the following scale of proportions is recommended. 
 
 Reading on hydrometer Number of gallons of water to 1 gallon 
 
 in degrees (Baum6). of the concentrated lime-sulphur. 
 
 35 9 
 
 34 8f 
 
 33 8i 
 
 32 8 
 
 31 7h 
 
 30 7i . 
 
 29 6f 
 
 28 , Qh 
 
 27 
 
 26 5| 
 
 25 5i 
 
 24 5 
 
 23 4^ 
 
 22 ' 4i 
 
 21 3| 
 
 20 3| 
 
 19 3i 
 
 18 3 
 
 17 2f 
 
 16 2h 
 
 15 2i 
 
 14 2 
 
 Regular Lime-sulphur Wash (for winter spray). 
 
 Lump lime 20 pounds 
 
 Sulphur 12 pounds 
 
 Water 50 gallons 
 
 Kerosene. — The use of kerosene or petroleum combinations 
 has given some of the most useful combinations and they 
 still have a wide range of usefulness, although at present 
 less used than the lime-sulphur solutions for scale insects. 
 Generally they may be applied to practically all kinds of 
 insects which are suctorial in habit and cannot be reached 
 by arsenical sprays, but they are especially efficient against 
 the scale insects at time of migration and against such soft- 
 bodied insects as the plant lice. In the preparation of the 
 kerosene emulsion it is extremely important that a thorough 
 emulsion be obtained so there will be no separation of oil 
 from the water, as there is much damage to the foliage if 
 this occurs. 
 
320 PRINCIPLES OF ECONOMIC ENTOMOLOGY 
 
 The standard formula for kerosene emulsion is as follows: 
 
 Hard soap h pound 
 
 Hot water (soft) 1 gallon 
 
 Kerosene (coal oil) 2 gallons 
 
 To form the emulsion take a gallon of soft water and 
 dissolve in it a half-pound of soap, then remove from fire, 
 add two gallons of kerosene, which should be thoroughly 
 mixed and agitated at once. One of the best methods is to 
 run the solution through a spray pump, driving it back into 
 the bucket from which the solution is drawn, and about 
 five or six minutes of this mixing will produce a perfect emul- 
 sion. It should be carried to such completion that there 
 will be no tendency for the oil to separate. Small quantities 
 may be made rapidly in the proper proportions by the use of 
 an egg-beater or by a process which produces a violent 
 agitation which may be maintained for some length of time. 
 This strong enjulsion should be kept in a cool place and 
 covered or in a tight receptacle and may be diluted as wanted 
 with soft water, the amount of dilution depending upon the 
 insects to be reached. For scale insects, one pint of strong 
 emulsion to nine parts water. Soft plant lice are readily 
 killed by a solution of one part of stock solution to fifteen 
 parts of water. 
 
 Tobacco Extract. — This is a very efficient contact insecti- 
 cide and may be used against many kinds of insects but 
 especially such forms as plant lice, thrips, and the better- 
 protected sucking insects. Various solutions are on the 
 market but the one termed Black Leaf 40, containing 40 
 per cent, nicotine sulphate, is one which seems to have 
 proved one of the best; this is used in dilutions of 1 part 
 to 300 of water to 1 part to 600 parts of water — for use in 
 winter time, when plants are dormant, and for summer use, 
 dilutions — 1 to 500, to 1 to 1000 are recommended for tender 
 insects such as plant lice. Similar solutions may be used for 
 parasitic lice and mites on domestic animals. 
 
 Tobacco dust may be used or an extract prepared from 
 this by steeping or soaking in w^ater overnight. In making 
 the preparation boil one pound of dust or stems to a gallon 
 
MEASURES FOR INSECT CONTROL 321 
 
 of water, and this may be diluted, one to two parts of water 
 and applied for leaf-sucking insects. 
 
 Pyrethrum or Persian Insect Powder. — This is a very power- 
 ful insecticide when properly prepared, but loses its strength 
 when exposed to air, so that particular care should be taken 
 to keep it in a tightly closed receptacle or it must be used 
 when quite fresh. It is a powdered material derived from the 
 grinding of the leaves or flowers and buds of the Pyrethrum 
 plant, the main supply coming from Dalmatia, but a consider- 
 
 
 1 
 
 1 
 
 1 
 
 1 
 
 ^PpliRly^ ^H' ' JB'^* 
 
 Bl 
 
 B^n^ 
 
 
 ^^^ 
 
 i^iMi 
 
 ■■I 
 
 k " 
 
 ■> ;--g^,*i, 
 
 
 Fig. 252. — An orchard demonstration in spraying. 
 (Photo. Ohio Exp. Sta.) 
 
 able amount being produced in California. It is a volatile 
 oil and it is the vaporization and contact of this which is 
 destructive to the insect. It may be used as a spray by the 
 dilution of one ounce of powder to two gallons of water, and 
 is available for saw-fly larvae and other pests upon currants, 
 gooseberries, etc., being especially valuable on account of 
 its not being poisonous to man or domestic animals. The 
 powder, blown into rooms is effective for the killing of 
 mosquitoes and flies, but for this purpose does not compete 
 21 
 
322 PRINCIPLES OF ECONOMIC ENTOMOLOGY 
 
 with some other measures. It may be used upon dogs and 
 eats for the kilHng of fleas by dusting in the hair. 
 
 Machinery. — For the application of these various insecti- 
 cides, a great many forms of spraying outfits, chisting 
 machines, etc., have been devised. These are now so thor- 
 oughly standardized and handled by reputable firms that 
 anyone may secure such outfits as may be needed for his 
 individual purpose. 
 
 Cultural Methods. — ^Another distinct group of measures 
 for insect control (the indirect methods) may include those 
 which have to do with methods of culture and alternation of 
 crops and various cultural methods which incidentally have 
 an effect upon the activities of insects. 
 
 First among these may be mentioned the general practice 
 of crop rotation which for a good many insects serves in an 
 admirable way to prevent undue multiplication of injurious 
 forms. Aside from its advantages in other ways, rotation 
 serves to dislodge or starve out a great number of insects 
 which are not able to migrate readily and which become 
 established in any field only after several years of uninter- 
 rupted development. For such forms the plowing up of the 
 fields or a change from one crop to another may prove an 
 almost perfect control. A striking example of this has been 
 noted in the case of the corn-root worm. In somewhat les- 
 ser degree the process is available for many of the pasture 
 and meadow insects which are dependent upon grasses as 
 their main food supply and which when grass is plowed 
 under, especially if this is done at a time when the insects 
 are in larval or in a known migratory stage, serves to destroy 
 them very efi^ectively. 
 
 In a general way plowing will cut off the food supply, some- 
 times will bury the insects to such a depth that they do not 
 extricate themselves. In this connection, however, it is some- 
 times very important that the condition of the insects be 
 known, as there are cases, such as white grubs, sod worms, 
 and wire worms, which if plowed under with the sod will, 
 if a second crop is planted soon, transfer their attack to the 
 new crop with very disastrous consequences. It frequently 
 
MEASURES FOR INSECT CONTROL 323 
 
 happens that com planted on sod land is in this way very 
 seriously injured. The precaution should be to plow under 
 long enough before the new crop is planted to allow oppor- 
 tunity for the starving out of insects which may be present 
 in the grass. 
 
 Another practise in this line is for such an arrangement of 
 crops that insects which naturally migrate from one crop to 
 another will be separated by a crop of different character, 
 something that will not serve them as a food supply. For 
 instance, the migration of the chinch bug from wheat fields 
 into corn fields may be prevented by the introduction of a 
 strip planted to potatoes, beans or some crop which is not 
 available as chinch bug food. 
 
 The use of an early planted crop for the purpose of attract- 
 ing insect egg deposition with the view of destroying the 
 insects so attracted and thus protecting the later crop, has 
 been in vogue for many years and is applicable to such 
 species as have several generations in a season. A good 
 example of this is the corn-ear worm which if attracted to 
 a small area of early planted corn which is fed to hogs at the 
 time the worms begin work will assist much in the preven- 
 tion of attacks on adjacent fields. 
 
 In some cases where an insect is especially destructive in 
 a certain area, resort may be had to the suppression of the 
 cultivation of a crop for one or two seasons, thus eliminating 
 food. This will largely diminish if not practically extermi- 
 nate such insects as are strictly dependent upon this crop for 
 existence. Naturally such a method is limited in application, 
 as the complete suppression of any crop in a certain district 
 is a difficult matter to accomplish. 
 
 Clean culture is often recommended as an important 
 aid in the suppression of insects, and there is no doubt that 
 for many species attention to the elimination of food plants 
 which assist them to survive and the cleaning up of litter 
 in which they may hibernate will accomplish a great deal 
 in the reduction of numbers and the consequent extent of 
 injury. Clean culture, however, must be taken in connec- 
 tion with a study of the habits of the species which it is 
 
324 PRINCIPLES OF ECONOMIC ENTOMOLOGY 
 
 desired to control and cannot be considered as an efficient 
 l^ractise for many insects that are troublesome on the 
 avera<]:e farm. Tn this coimection it may be stated that it 
 is good entomological j)ractise to use wire fences in place 
 of the old rail or board fences, and it is a good plan to culti- 
 vate as close as possible to fence lines with the consequent 
 reduction of the growth of weeds, bushes, and so on. 
 
 Another matter which deserves attention is a close guard- 
 ing against the introduction of pests in seed or along with 
 introduced ])lants, as many of the serious pests are readily 
 transferred from place to place in such materials as straw 
 and various kinds of seed packages and thus gain a foot- 
 hold in a locality in which they have not been troublesome 
 before. 
 
 NATURAL ENEMIES. 
 
 Insects are preyed upon by many natural enemies — birds, 
 reptiles, toads, spiders, and these serve as checks to their 
 inordinate increase. Bird protection has been strongly 
 urged as an aid in insect control and certainly all or nearly 
 all of our common field birds are best allowed all the pro- 
 tection possible. Especially the small insectivorous birds 
 such as wrens, swallows, chickadees, titmice, etc., should be 
 given all the protection possible. Spiders are also generally 
 useful rather than injurious and should be undisturbed. 
 
 PREDACEOUS AND PARASITIC INSECTS. 
 
 The position of the predaceous and parasitic insects is one 
 of considerable complexity, since their attacks may be 
 directed against both injurious and beneficial forms, and 
 their relation to human interests depends, of course, upon 
 the nature of the insects which they attack. In a general 
 way the carnivorous species feed upon the herbivorous ones, 
 and the herbivorous ones being ordinarily the most destruc- 
 tive to valuable crops, the average result may be looked 
 upon as advantageous. The study of these natural enemies 
 of the injurious insects has formed a considerable part of 
 
PREDACEOUS AND PARASITIC INSECTS 325 
 
 economic entomology, and the importance of the subject 
 has been pretty generally recognized, though different 
 workers have assigned quite different value or importance to 
 to the subject. 
 
 Predaceous insects are those which attack and devour 
 other insects, possibly quite different kinds of insects, and 
 do it without sacrificing their own activity or independence. 
 Parasitic insects, using this term as it applies more particu- 
 larly to economic entomology, are those which are dependent 
 for a larger or smaller part of their existence upon some 
 particular kind of insect host. Nearly all are internal 
 parasites and in a great majority of cases the entire develop- 
 ment of the individual from the egg to pupa or adult stage 
 is passed within the body of a single individual host. Some- 
 times a large number of individuals will develop within a 
 single host, as in case of the minute ichneumons which 
 parasitize the larger caterpillars. 
 
 It must be noted here that a parasite itself may be para- 
 sitized by another species called a "secondary" parasite 
 which, by reducing the numbers of the parasitic species, 
 would become from the economic stand-point injurious. 
 This, again, in some instances may support still another 
 parasite, a so-called "tertiary" parasite, which by reducing 
 the numbers of the secondary parasite would be detrimental, 
 and a fourth, where such occurs, again assumes the opposite 
 role. It is evident where such a complex condition of para- 
 sites exists that it is practically impossible to adopt any 
 means of encouraging the beneficial or destroying the inju- 
 rious ones, and that this complex system of wheels within 
 wheels must be allowed to work out its own conclusion in the 
 balance of nature. 
 
 For most species there is perhaps but little that can be 
 done in the way of preserving the beneficial parasites or of 
 facilitating their work. We simply allow them to go on un- 
 molested, serving so far as they may, as a natural check upon 
 the injurious species. Many of our destructive insects are 
 insects that without this check would be seriously destruc- 
 tive, the regular attacks of these parasites serving very 
 
326 PRINCIPLES OF ECONOMIC ENTOMOLOGY 
 
 efi'ectively to keep the destructive species in reasonable 
 bounds and often preventing it from causing any serious 
 loss. The Hessian fly is certainly kept in check during a 
 considerable portion of the time by just such agencies, and 
 we can scarcely doubt that if the parasites of this species 
 were eliminated and other conditions unaffected, the losses 
 incurred would be enormously increased. 
 
 With some species it may be possible to assist the para- 
 sitic forms or to preserve them in such manner as to get the 
 advantage of their service. For instance, the cabbage 
 butterfly is very commonly parasitized by a small ichneu- 
 monid {Pteromalus) which issues from the pupae, and it is 
 evident that if the pupae were gathered and instead of being 
 crushed were enclosed in wire screen of such mesh as to 
 retain the issuing butterflies but allow the free escape of 
 the minute parasites, there would be a destruction of the 
 healthy butterflies without any reduction in the numbers of 
 the parasites. Again, in the case of the Hessian fly, care, 
 as to the time when the stubble is burned or plowed under 
 in order to allow opportunity for escape and survival of 
 the parasites, might be of special service in their protection. 
 In California extensive shipments of lady bugs from the 
 northern part of the State to the Imperial valley to prey 
 upon the plant lice affecting melons is claimed to have 
 accomplished much in their control. 
 
 On the whole, however, the utilization of parasites in a 
 direct manner can hardly be depended upon as a very great 
 advantage, especially because of the difficulty in so training 
 the average cultivator that he will be able to distinguish 
 between parasites and non-parasitic forms, and adapt his 
 practice to accommodate them. 
 
 A more important phase of the subject perhaps is found 
 in the transportation of parasitic species from one country 
 to another where an injurious species has been introduced 
 without the introduction of its native enemy. It has already 
 been suggested that the original habitat of an injurious 
 insect is a matter of great importance, especially with 
 reference to its natural parasites, and a number of instances 
 
EXCLUSION AND RESTRICTION 327 
 
 are now in evidence showing the possibility of controlling 
 injurious, introduced species by means of the introduction of 
 the native enemies. The most conspicuous is that of the 
 cottony cushion scale, introduced into California several 
 years ago, and in more recent years the very extensive intro- 
 duction of predaceous and parasitic enemies of the Gipsy 
 and brown-tail moths in the New England States for the 
 control of these very destructive imported pests. 
 
 EXCLUSION AND RESTRICTION. 
 
 These are most important means of controlling insect 
 depredations. Formerly the entomologist devoted his 
 entire attention and effort to the study of native species 
 but now his attention is largely directed toward exclusion 
 from and restriction in the United States of new insects. 
 Until recently in the introduction of new plants from foreign 
 countries, no attention has been paid to the new insects 
 introduced with them. An important part of the work of 
 the entomologist in the future will be to study the insects 
 of other countries— not only those that are now destructive 
 there but those that do no particular damage, yet when 
 the natural checks are removed, are likely to become 
 destructive. 
 
 Special attention must be paid to those insects which are 
 native in those countries from which we import a greater 
 part of our plants. Some of the foundation principles in the 
 study are : 
 
 1. An insect, coming from another country, is more likely 
 to become destructive here if it comes from a somewhat 
 similar climate, and if the food plants are somewhat closely 
 related to those of its native country. 
 
 2. Insects coming from different climates may, if they have 
 a wide range of food plants, adapt themselves to the new 
 climate. It will then be proper to consider tropical species, 
 especially if their food plants are widely distributed and 
 have nearly related species in the country to which they are 
 brought. 
 
328 PRINCIPLES OF ECONOMIC ENTOMOLOGY 
 
 3. Tropical insects that arc limited to tr()})ical ])laiits for 
 food, will have little importance in temperate regions excej)t 
 in greenhouses. 
 
 Most of the scale insects are tropical and in this climate 
 are on the borderline of their destructive region, hut on 
 account of their general food habits the\' constitute a general 
 pest. 
 
 The question of the control of the distribution of the 
 destructive species is yet a new problem and one over which 
 there is considerable dispute; any measure intended to exclude 
 a foreign species must be adapted to a particular species, as 
 a general law will not suffice. Even the general exclusion of 
 the food plant will not alone be effective in keeping out the 
 pest, as it may have other means of dispersal. 
 
 Inspection and enforcement of restrictions at the port of 
 entry are being quite generally adopted. Inspection is most 
 effective when applied to plants. Sometimes it is necessary to 
 introduce a foreign species to prey on another foreign insect 
 that is already here, as was the case with cottony cushion 
 scale in California. 
 
GLOSSARY OF THE TERMS USED IN 
 ENTOMOLOGY. 
 
 Abdomen. The posterior region of the insect body. 
 
 Abiogenesis. Spontaneous generation. 
 
 Abraded, Scraped or rubbed. 
 
 AcALYPTRATA. Thosc muscid flies in which alulse are absent or 
 rudimentary. 
 
 Aculeate. Prickly; armed with a sting. 
 
 Acuminate. Tapering to a long point. 
 
 Addorsal. Close to but not on the middle of the dorsum. 
 
 Adephagous. Belonging to the Adephaga; pentamerous, predatory, 
 terrestrial beetles with filiform antennae. 
 
 Adpressed. Contiguous or pressed to. 
 
 Agamic. Reproducing without union with a male. 
 
 Agamogenesis. Reproduction without fertiUzation by a male; 
 parthenogenesis. 
 
 Agglutinate. Glued together in a mass. 
 
 Aggregated. Crowded together. 
 
 Ala (pi. Al^). Wing or wings. 
 
 Alary. Relating to wings. 
 
 Alate. Winged. 
 
 Alternation of Generations. Periodic production of partheno- 
 genetic females in a species that occurs in both sexes. These females 
 produce both sexes. Examples occur in Cynipidae and in some 
 Homoptera. 
 
 Alul^. a pair of membranous scales above the halteres, behind the 
 root of the wing, one above or before the other; the anterior attached 
 to the wing and moving with it, the posterior fastened to the thorax 
 and stationary. Occurs in Diptera. Synonyms calyptra; squama; 
 squamula; lobulus; axillary lobe; aileron; scale; tegulse. In Cole- 
 optera, a membranous appendage of the elytra which prevents 
 dislocation. 
 
 Alulet. The lobe at basal portion of wing in Diptera. 
 
 Ametabola. Insects not having obvious metamorphosis, the larvse 
 resembling the adult and the pupae being active. 
 
 Amnion. The inner of the two membranes enclosing the embryo. 
 
 Amphimixis. The mingling of the germ plasm of two individuals. 
 
 Ampulla. In Orthoptera, an extensile sac between the head and 
 prothorax, used by the young in escaping from the ootheca, and later 
 in moulting. In Heteroptera, a blister-like enlargement at the middle 
 of the anterior margin of the prothorax. 
 
 Anal. Pertaining or attached to the last segment of the abdomen. 
 
 Anal angle. That angle on the secondaries nearest the end of the 
 abdomen when the wings are expanded. The angle between the inner 
 and outer margin of any wing. 
 
 (329) 
 
330 GLOSSARY OF TERMS USED IN ENTOMOLOGY 
 
 Anal appendages. The external genital parts. 
 
 Anal area. In Orthoptcra and Neuroptera, the hinder or anal 
 portion of a wing within the anal vein. 
 
 Anal field. That area on the tegmina of Orthoptera corresponding 
 to the anal area of the secondaries. 
 
 Anal plate. In caterpillars, the shield-like covering of the dorsum 
 of the last segment. 
 
 Annulate. Marked with colored rings or bands. 
 
 Annulus. a ring. 
 
 Ante -APICAL. Before or in front of the apex. 
 
 Antennae. Two-jointed organs of sensation situated on the head. 
 
 Antepectus. The lower surface of the prothorax. 
 
 Antigeny. Sexual diversity. 
 
 Anus. The posterior opening of the digestive tract. 
 
 Apex. The terminal portion of any organ of body, the part farthest 
 away from the base. 
 
 Appendiculate. Bearing appendages. 
 
 Appendix. A part added or attached to another part. 
 
 Apterous. Without wings. 
 
 Aquatic. Living in the water. 
 
 Araneiform. Spider-like in appearance. 
 
 Arboreal. Living in or on trees. 
 
 Arborescent. Branching. 
 
 Arcuate. Bowed or curved. 
 
 Arenose. Sandy, not smooth. 
 
 Areola. A small cell on the wings of certain Hemiptera. 
 
 Arista. A specialized bristle or process on the antenna of certain 
 Diptera. 
 
 Arolium. Cushion-like pads on the tarsi of many insects. 
 
 Arthropoda, Jointed animals having jointed appendages. 
 
 Articulate. Divided into distinct joints. 
 
 Articulation. Joint; place where two joints meet. 
 
 Asexual. Without sex. Reproduction which does not involve the 
 union of individuals of different sexes. Reproduction by budding, etc. 
 
 Ater. Deep black, 
 
 Atomarius. With minute points or dots. 
 
 Bifid. Split, two parts. 
 
 Bifurcate. Divided; forked. 
 
 Bionomics. The habits, breeding, and adaptations of living forms. 
 
 BisERRATE. Saw^-toothed on two edges. 
 
 BiviTTATE. Having two longitudinal stripes. 
 
 Brachycerous. Having short three-jointed antennae, Diptera. 
 
 Brachypterous. Short- winged. 
 
 Bristle. A short, stiff hair. 
 
 Buccal. Relating to the mouth cavity. 
 
 Bulla. A blister or blister-like structure. 
 
 CiECUM, A blind sac or tube opening into the alimentary canal. 
 Calypter. In Diptera, the alula when it covers the haltere. 
 Campodeiform. Resembling campodea. 
 
 Canaliculate. Grooved longitudinally, with a concave line in the 
 middle. 
 
GLOSSARY OF TERMS USED IN ENTOMOLOGY 331 
 
 Cancellate. Cross-barred; latticed. 
 
 Capillary. Hair-like; long and slender. 
 
 Capitate. Terminating in a little head or knob. 
 
 Caprification. Process of fertilization of Smyrna figs by Blasto- 
 phaga through the medium of "caprifigs." 
 
 Carabidoid. Resembling a Carabid. 
 
 Carina. An elevated ridge. 
 
 Carnivorous. Flesh-eating. 
 
 Cauda. The tail; any process resembling a tail. 
 
 Caudad. Toward the posterior region of the body. 
 
 Caudal. Pertaining to the posterior end of the body. 
 
 Caudal set^. Thread-like processes at the end of the abdomen. 
 
 Caudate. Having tail-like extensions. 
 
 Caverniculous. Cave-inhabiting. 
 
 Cell. Space within the veins on the wing. 
 
 Cellule. A small space included between the veins on the wing. 
 
 Cephalad. Toward the head. 
 
 Cephalic. Belonging to the head. 
 
 Cervical. Relating to the neck. 
 
 Chaetotaxy. The science dealing with the arrangement and 
 nomenclature of the bristles on the body of insects. 
 
 Chelate. Having a claw. 
 
 Chitin. The material of which the hard parts of the insect body are 
 formed. 
 
 Chitinous. Composed of chitin or similar to chitin. 
 
 Chrysalis — id. The intermediate stage between larva and adult; 
 see pupa. 
 
 Cicatrix. A scar; an elevated, rigid spot. 
 
 Cilia. Fringes. 
 
 CiLiATE. Fringed; set with parallel hairs or bristles. 
 
 Clasper. a chitinized process, free or attached to the inner sides 
 of valves or other lateral pieces and serving to hold the female parts 
 during' copulation; the harpes. 
 
 Claval suture. Indentation separating the clavus at the base of 
 the hemelytra in Hemiptera. 
 
 Clavate. Club-shaped; thickening gradually toward end. 
 
 Clypeus. The anterior median portion of the head to which the 
 labrum is usually attached. 
 
 CoARCTATE. Contracted; compact. 
 
 Cocoon. Silky covering enclosing pupa. 
 
 CoLLUM. The neck or collar. 
 
 Colon. The large intestine. 
 
 Connate. United at base, or along the whole length. 
 
 CoNNEXivuM. The prominent abdominal margin of Heteroptera at 
 junction of dorsal and ventral plates. 
 
 CoPROPHAGUS. Feeding on excrement on or decaying vegetable 
 matter of an excrementitious character. 
 
 Cordate. Heart-shaped. 
 
 Coriaceous. Leather-like. 
 
 CoRiuM. The elongate middle section of the hemelytra which 
 extends from base to membrane below the embolium. 
 
 Cornicles. The honey-tubes in plant lice. 
 
332 GLOSSARY OF TERMS USED IN ENTOMOLOGY 
 
 Costa. An elevated ridge that is rounded at its crest; the thickened 
 anterior margin of a wing. 
 
 Costal area. The area behind the costal vein. 
 
 Costal cell. The area inclosed between the costal antl subcostal 
 veins. 
 
 Coxa. The basal segment of the leg. 
 
 CoxAL cavity. The opening or space in which the coxa articulates. 
 
 Crenate. Scalloped. 
 
 Crepuscular. Active at dusk. 
 
 Cristate. Crested. 
 
 Dentate. Toothed. 
 
 Dentate-serrate. Tooth-serrated: the denticulations themselves 
 being serrated on their edges. 
 
 Dichoptic. Eyes separated by front, not contiguous. 
 
 DicHOTOMOUs. Forked, dividing by pairs. 
 
 Dimorphic. Occurring in two well-marked forms. 
 
 Dimorphism. A difference in form, color, etc., between individuals 
 of the same species, characterizing two distinct types. 
 
 Dioecious. Having distinct sexes. 
 
 DiscAL. On or relating to the disk of any surface or structure. 
 
 DiSTAD. Toward the distal end. 
 
 Distal. That part of a joint farthest from the body. 
 
 Divergent. Spreading out from a common base. 
 
 Dominant. A character more constant and conspicuous than any 
 other. 
 
 Dorsad. Toward the upper surface. 
 
 Dorsal. Of the back. 
 
 Dorsum. The upper surface. 
 
 Drone. The male bee in Hymenoptera. 
 
 Ecaudate. Without tails or tail-like processes. 
 
 EcDYSis. Moulting or casting of the skin. 
 
 Ecology. The science of the relation of organisms to each other 
 and to their surroundings. 
 
 EcTAD. Extending outwardly from within. 
 
 EcTAL. Relating to the outer surface. 
 
 Elytra. The anterior leathery or chitinous wings of beetles. 
 
 Embolium. The narrow sclerite extending along the anterior margin 
 of the hemelytra, from base to cuneus or membrane, in Heteroptera. 
 
 Empodium. The small process between the pul villi in Diptera. 
 The bifid pseudotarsi between the claws in Coleoptera. 
 
 Ensiform. Sword-shaped. 
 
 Entad. Extending inwardly. 
 
 Ental. Pertaining to the centre of the body cavity. 
 
 Entire. With an even, unbroken margin. 
 
 Entomogenous. Growing in or on an insect. 
 
 Entomophagous. Insect-feeding. 
 
 Episternum. The anterior and larger lateral thoracic sclerite 
 between the sternum and notum. 
 
 Epizoa. Insects that infest the body surface of animals. 
 
 Ergatoid. Wingless ants, sexually developed. 
 
GLOSSARY OF TERMS USED IN ENTOMOLOGY 333 
 
 Eruciform. Caterpillar-like in appearance. 
 
 Exotic. An introduced species, not native to the place found. 
 
 ExsERTED. Protruded. 
 
 Facet. One of the small divisions of the compound eye. 
 Fasciate. Banded. 
 
 Femur (pi. femora). The thigh between the coxa and tibia. 
 Filiform. Thread-like. 
 
 Flabellate. With long, flat processes folding like a fan. 
 Formic. Pertaining to or derived from ants. 
 Formicary. An ant's nest or ant hill. 
 
 Front. Anterior portion of the head between the base of antennae 
 and below the ocelli. 
 Fumose. Smoky. 
 
 FuNGicoLOUS. Living in or on fungi, 
 FuRCA. A fork or forked process. 
 Furcate, Forked. 
 Fuscous. Very dark brown. 
 
 Gena. Cheek; that portion of the head below the eyes on each side 
 extending to the gular suture. 
 Generation. Brood. 
 
 Genitalia. External organs of reproduction and their appendages. 
 Granulated. Covered with small grains. 
 Gregarious. Living in groups or communities. 
 Griseus. Light gray. 
 Guttate. Spotted, light spots on dark ground. 
 
 Habitat. The locality in which an insect lives. 
 
 Haustellate. Formed for sucking. 
 
 Haustellum. Sucker; the part of the mouth through which liquids 
 are sucked. 
 
 Hermaphrodite. A bisexual individual. 
 
 Heterogamy. Alternation of generations, two sexual or a sexual 
 and a parthenogenetic. 
 
 Hibernaculum. a tent or sheath in which a larva hibernates. 
 
 Hibernate, To pass the winter in a dormant condition. 
 
 Hypermetamorphosis. The case in which an insect passes through 
 more than the normal stages of development. 
 
 Hyperparasite. a parasite that is parasitic upon another parasite. 
 
 Imaginal Pertaining to the adult or imago. 
 Imago, The adult or sexually mature insect. 
 Infumated. Clouded. 
 
 Infuscated. Smoky gray-brown, with a blackish tinge. 
 Inquiline. a species living in a gall made by another species, not 
 as a parasite but as a guest. 
 
 Inquilinous. Living as guests in the homes of others, 
 Insectary, a place where insects are bred for the purpose of study , 
 Instar. The period or stage between moults in the larva. 
 Integument. The outer covering to the insect body. 
 Intima. The lining membrane of the trachea. 
 
334 GLOSSARY OF TERMS USED IN ENTOMOLOGY 
 
 Invaginate. When a tubular or vesicular part is turned inward or 
 retracted within the body wall. 
 
 Iridescent. Reflecting the prismatic colors. 
 
 Iris. The circle which, in an ocellate spot surrounds the pupil. ^ 
 
 Irrorate. Marked with fine points. 
 
 Iso. Equal. 
 
 Juga. The lateral anterior lobes of a Heteropteron ; each side of 
 the tylus. 
 
 Labellum. The sensitive ridge tip of the mouth structures of 
 certain Diptera; a prolongation of the base of the rostrum in Coleoptera 
 and Hemiptera. 
 
 Labial. Pertaining to the labium. 
 
 Labium. The lower lip. 
 
 Labrum. The upper lip. 
 
 Lacinia. The inner lobe of the first maxilla, articulated to the stipes, 
 bearing brushes of hairs or spines. 
 
 Lacuna. Irregular cavities. 
 
 Lamella. A thin plate. 
 
 Lamellate. Divided laterally into distinct leaf -like plates. 
 
 Lanceolate. Spear-shaped. 
 
 Larva. The second stage in the development of the insect, follows 
 immediately after the egg stage. 
 
 Larvarium. The shelter-case of the larva. 
 
 Laterad. Toward the side and away from the median line. 
 
 Lateral. On the side. 
 
 Littoral. Living along the seacoast or in the shore debris. 
 
 LoRA. The chitinous bands connecting the submentum with the 
 cardo of the maxilla. 
 
 Lumen. The cavity or hollow part of an organ or tube. 
 
 Lunula. A small crescent-shaped mark. 
 
 LuNULE. A lunate mark or crescent. 
 
 Macroch.et.^. The long bristles occurring singly on the body of 
 Diptera. 
 
 Macropterous. Long or large winged. 
 
 Macula. A colored mark larger than a spot and of no definite shape. 
 
 Maggot. The footless larva of Diptera. 
 
 Mammilate. With nipple-like protuberances. 
 
 Mandible. The lateral upper jaws of a biting insect. 
 
 Mandibulate. Having jaws or mandibles. 
 
 Maxilla. Jaws; one on each side of the mouth immediately 
 beneath the mandibles. 
 
 Maxillary. Belonging to the maxilla. 
 
 Meconium. The substance excreted by certain metabolic insects 
 soon after their emergence from the chrysalis. 
 
 Mediad. Toward the middle. 
 
 Medial. Referring to or at the middle. 
 
 Median. Middle. 
 
 Melanic. Blackish. 
 
GLOSSARY OF TERMS USED IN ENTOMOLOGY 335 
 
 Melanism. An abnormal darkening. 
 
 Mellifera. Honey-makers. 
 
 Mentum. a labial sclerite bearing the movable parts. 
 
 Mesenteron. The middle portion of the primitive intestinal canal ; 
 the midgut. 
 
 Meso-. Middle. 
 
 Mesonotum. The primitively upper surface of the middle thoracic 
 ring. 
 
 Meta-. Posterior. 
 
 Metabolism. Transformation, changes of food into tissue and of 
 tissue into waste products. 
 
 Metanotum. The primitively upper surface of the third or posterior 
 thoracic ring. 
 
 Metathorax. The third thoracic ring or segment. 
 
 Metopidium. The anterior declivous surface of prothorax in Mem- 
 bracidse. 
 
 Microch^t^. Small bristles, as opposed to macrocha^tae, in Diptera. 
 
 Micron. The unit of microscopic measurement. 
 
 Mimetic. Mimicry of appearance but not structure. 
 
 Mimicry. The resemblance of one animal to another not closely 
 related. 
 
 Monoecious. The combining of both sexual elements in one indi- 
 vidual. 
 
 Moult. The transformation of a larva from one instar to another; 
 the cast skin of a larva that has moulted. 
 
 Ne arctic. Temperate and arctic North America, including Green- 
 land. 
 
 Necrophagous. Living in or on carrion. 
 
 Nectaries. Honey-tubes. 
 
 Neotropical. That part of the earth's surface embraced in the 
 greater part of Mexico, West Indies and South America. 
 
 Nocturnal. Night-flying. 
 
 Obsolete. Indistinct, nearly or entirely lost. 
 
 Obtect. Wrapped in a hard covering. 
 
 Obtected. Covered with a chitinous case which conceals appendages 
 but through which their outlines are revealed. 
 
 Ocelli. Plural of ocellus. 
 
 Ocellus. A simple eye. 
 
 Ontogeny. The development of the individual as distinguished from 
 that of the species. 
 
 Ootheca. The covering of an egg mass. 
 
 Operculum. A lid. 
 
 Optic. Relating to the organs of vision. 
 
 Oral. Pertaining to the mouth. 
 
 Oriental. In geographical zoology as used by Wallace, that part of 
 the earth's surface including Asia east of the Indus River, south of the 
 Himalayas and the Yangtse-kiang watershed, Ceylon, Sumatra, Java, 
 and the Philippines. 
 
 Ova. Eggs. 
 
336 GLOSSARY OF TERMS USED IN ENTOMOLOGY 
 
 Ovum. An egg. 
 
 OviPosiTiON. The act of depositing the eggs. 
 
 Ovipositor. The structure by means of which the eggs are placed. 
 
 P.EDOGENESis. Reproduction in the hirval stage. 
 
 Palearctic. Relating to that part of the earth's surface including 
 Europe, Africa north of Sahara, and Asia as far as the southern edge of 
 the Yangtse-kiang watershed and the Himalayas, and west to the Indus 
 River. 
 
 Pallid. Pale. 
 
 Palmate. Like the palm of the hand with finger-like processes. 
 
 Palpus. Articulated moveable appendage in the mouth of insects. 
 
 Parasitic. Living on or in another animal or insect and dependent 
 on the host for food and support. 
 
 Parthenogenesis. Reproduction by direct growth of germs from 
 egg-cells without fertilization by the male. 
 
 Parthenogenetic. See asexual. 
 
 Pectus. The ventral portion of the thorax. 
 
 Pelagic. Living in the open sea. 
 
 Pellucid, Colored, but transparent; sometimes no color. 
 
 Petiolate. Placed on a stalk. 
 
 Phylogeny. The developmental relationship of a genus, family, or 
 other group. 
 
 Pile, A fur-like covering. 
 
 PiLiFERous. Having a covering of pile. 
 
 Plicate. Folded like a fan, plaited. 
 
 Plumose. Feathered, like a plume. 
 
 Pollinose. Covered with a pollen-like dust. 
 
 Polyandry. Mating of one female with more than one male. 
 
 Polyembryony. Production of more than one embryo from one egg. 
 
 Polygamy. Mating of one male with more than one female. 
 
 Posterior. Hinder or hindermost; opposed to anterior. 
 
 Predaceous. Living upon other organisms. 
 
 Predatory, Predaceous. 
 
 Primaries. The anterior or fore-wings. 
 
 Primitive. Simple in character; of an early or ancient type. 
 
 Pro-. Anterior to. 
 
 Proboscis. The extended mouth structure. 
 
 Proximad. Toward the proximal end. 
 
 Proximal. That part of an appendage nearest the body. 
 
 Pruinose. Hoary, covered with fine dust, / 
 
 Pseud imago. Subimago. 
 
 Pseud- or pseudo-. Prefix meaning false. 
 
 Pseudogyne. a female that reproduces without impregnation. 
 
 Pseudova. Egg-like germ cells capable of development without 
 fertilization. 
 
 Pulverulent. Powdery. 
 
 Pupa. The intermediate stage between larva and adult. 
 
 PuPARiUM, The thickened larval skin within w^hich the pupa is 
 formed. 
 
 Pupate. To become a pupa. 
 
 Pupation. Becoming a pupa. 
 
GLOSSARY OF TERMS USED IN ENTOMOLOGY 337 
 
 Pygidium. The last dorsal segment left exposed by the elytra. 
 Pygofer. The last segment of the abdomen in certain Homoptera, 
 especially the lateral margins which appear in ventral view. 
 
 Radial. Pertaining to the radius or radial vein. 
 Rostrum. A snout-hke prolongation of the head. 
 
 ScABER. Rough, uneven. 
 
 Scape. The second articulation of the antenna?, often elongated. 
 
 Scutum. The second dorsal sclerite of the meso- and metathorax. 
 
 Sensoria. The circular openings covered by membrane on the 
 antennae or legs of plant lice. 
 
 Serrate. Like the teeth of a common saw. 
 
 Sessile. Closely attached. 
 
 Setaceous. Bristle-shaped, slender, tapering. 
 
 Social. Living in communities. 
 
 Spermatogenesis. Development of the spermatozoa. 
 
 Spinneret. Any organ consisting of an internal tube, terminating 
 in a pore, spine or process, producing a silky or waxy fiber. 
 
 Spiracle. A breathing pore opening to the trachea. 
 
 Stage. A period in the course of development. 
 
 Stellate. Star-shaped. 
 
 Sterile. Incapable of reproduction. 
 
 Sternite. The ventral piece in a ring or segment. 
 
 Subimago. The stage in ephemerids and some other insects just 
 after emergence from the pupa and before the final moult during flight. 
 
 Tenent hair. Specialized hair adapted for clinging or clasping. 
 
 Teneral. That state of the imago just after its exclusion from pupa 
 or nymph, in which neither coloring nor clothing is fully developed. 
 
 Teres, terete. Cylindrical. 
 
 Tergal. Belonging to the primitively upper surface. 
 
 Thorax. The second or middle portion of the insect body, bearing 
 the true legs and wings; made up of three sections, the pro-, meso- 
 and metathorax. 
 
 Trachea—^. The breathing tubes of insects. 
 
 Tracheate. Supplied with a trachea. 
 
 Tracheoles. The capillary trachea of the adult as they develop 
 in masses in the larva; very small, slender trachese. 
 
 Transition zone. The transcontinental belt in which the austral 
 and boreal elements overlap; it is divided into a humid or Alleghanian 
 area, a western arid area, and a Pacific coast humid area. 
 
 Trochantine. The basal part of the trochanter when it is two- 
 jointed. 
 
 Tumid. Swollen. 
 
 Tylus. The anterior central lobe of the head in Hemiptera. 
 
 Unicolorous. Of one color throughout. 
 
 Vaginate. Inclosed in a bivalved sheath. 
 
 Valve or Valvul.e. The expanded plate-like galea of the maxilla in 
 many Hymenoptera. 
 22 
 
338 GLOSSARY OF TERMS USED IN ENTOMOLOGY 
 
 Valve. A small, transverse or triangular piece behind the last full 
 ventral segment, at the base of plates in male Jassidic and allies. 
 
 Venation. The system of chitinous framework supporting the wings. 
 
 Venter. The inferior or under portion of the abdomen. 
 
 Vestigial. Undeveloped or degenerate; the trace or remnant of a 
 previously functional organ. 
 
 Vestiture. The surface covering. 
 
 Viscera. The internal organs of the body. 
 
 Visceral. Pertaining to the viscera. 
 
 Vitta. a longitudinal, colored line. 
 
 Vittate. Striped. 
 
 Viviparous. Bearing living young. 
 
 Wing pads Undeveloped wings of pupa or nymph. 
 
INDEX. 
 
 Abdomen of insects, structure, 42 
 
 Acanthidse, 147 
 
 Acarina, 25 
 
 Acrididse, 59 
 
 Adalia bipunctata, 177 
 
 Adult stage of insects, 47 
 
 Agallia sanguinolenta, 107 
 
 Alabama argillacea, 227 
 
 Aleyrodidae, 129 
 
 AKalfa caterpillar, 243 
 
 weevil, 195 
 American silk worm, 240 
 Ametobolic, 48 
 Anasa tristis, 156 
 Anatomy of grasshopper, 39 
 Anopheles maculipennis, 249 
 
 punctipennis, 249, 250 
 Anosia plexippus, 245 
 Antenna}, 38 
 
 Anthonomus grandis, 198 
 Ant lions, 169 
 Ants, 305 
 
 Apanteles glomeratus, 296, 297 
 Aphaniptera, 50 
 Aphanothrips striata, 90 
 Aphidida?, 117 
 Aphids, 117, 118 
 Aphis maidis, 123 
 
 maidi-radicis, 123 
 Aphrophora 4-notata, 104 
 Apidse, 310 
 
 Appendages of insects, head, 38 
 Apple aphis, 126 
 
 leaf hopper, 115 
 
 maggot, 287, 288 
 Apterygota, 48 
 Arachnida, 22 
 Aradida), 314 
 
 Araneida, 24 
 Argas miniatus, 31 
 
 persicus, 31 
 
 reflexus, 30 
 Argentine ant, 307, 309 
 Armored scales, 134 
 Army worm, 227 
 Arphia sulphurea, 67 
 Arsenate of lead, 316 
 Arsenical bran mash, 317 
 Arthropoda, 17 
 Aspidiotus perniciosus, 137 
 Assassin bugs, 145 
 Athysanus exitiosus, 113 
 
 obtutus, 106 
 Atropos, work of, 82 
 
 divinatoria, 83 
 Auchenorhynchi, 94 
 
 B 
 
 Bag-w^orm moths, 207 
 Balaninus obtusus, 198 
 
 proboscideus, 196, 197 
 Bark beetles, 203 
 
 hce, 130 
 Basilarchia archippus, 247 
 Beach locust, 65 
 Bed-bug, 147 
 Bee moth, 213 
 Bees, 310 
 
 and wasps, 291 
 Beetles, 172 
 
 Belostoma americana, 144 
 Belostomidse, 142 
 Bembecidae, 310 
 Bembecina?, 308 
 Benacus griseus, 144 
 Bird lice, 83 
 
 (339) 
 
340 
 
 INDEX 
 
 Bird tick, 28 
 
 Bittacus, 170 
 
 Black flies, 2G0 
 
 Blattida?, 55 
 
 Blissus leucoptcrus, 151 
 
 Blood-sucking cone nose, 145 
 
 Blow flv, 277, 286 
 
 Blue-bottle fly, 285 
 
 Body structure, 38 
 
 Boir weevil, 198 
 
 worm, 226 
 Book lice, 81 
 Boreus, 170 
 Bot flies, 267 
 Box elder bug, 156 
 Braconidiie, 296 
 Bran mash, arsenical, 317 
 Bristle tails, 48 
 Brown-tailed moth, 233 
 Bruchidte, 193 
 Buffalo gnats, 260 
 
 treehopper, 99 » 
 
 Bumble bee, 310 
 Buprestidse, 181 
 Butterflies, 241 
 Bythoscopidse, 107 
 
 Cabbage butterfly, 242 
 Cacsesia roseana, 215 
 Caddice flies, 170 
 Calosoma calidum, 173 
 
 scrutator, 173, 174 
 
 sycophant a, 174 
 Camnula pellucida, 63 
 Campodea, 48 
 Canker worm, 225 
 Capsidse, 150 
 Carabidse, 173 
 Carpet beetles, 179 
 
 moth, 222 
 Carpocapsa pomonella, 215 
 
 saltitans, 218 
 Carrion beetles, 174 
 Cat flea, 290 
 Cattle louse, biting, 85 
 
 tick, 31 
 Cecropia moth, 240 
 Cerambycidse, 185 
 Cercopida}, 104 
 
 Ceresa bubalus, 90 
 Ceuthophilus, 68 
 Chalcidida), 296, 300 
 Chalcis ovata, 300 
 Chestnut weevil, 190 
 Chiggers, 26 
 Chilopoda, 17 
 I Chinch bug, 151 
 I Chionaspis furfurus, 136 
 I salicis, 135, 136 
 I Chion cinctus, 187, ISS 
 1 Chironomidae, 253 
 Chrysobothris femorata, ISl 
 I Chrysomelida?, 190 
 Chiysopa oculata, 167 
 Chrysopidse, 165 
 Cicada killer, 310 
 Cicadidai, 94 
 Cicadula 6-notata, 114 
 Cicindelidae, 173 
 Cimbex americana, 292 
 Cimex lectularius, 147, 14S 
 Circulatory system of insects, 43 
 Classification of insects, 4S 
 CUck beetles, 180 
 Clisiocampa americana, 235 
 Close wings, 214 
 Clothes moth, 222 
 Clothilla, 82 
 Clover-flower midge, 254 
 
 leafhopper, 107, 108 
 
 -leaf weevil, 195 
 
 -root borer, 205 
 
 -seed caterpillar, 219 
 Clypeus, 40 
 Coccidse, 130 
 , Coccinse, 132 
 I Coccinellidse, 175 
 ! Cockroaches, bb 
 Codling moth, 215 
 Coleoptera, 50, 172 
 CoHas philodice, 245 
 Collembola, 48, 54 
 ! Colorado potato beetle, 190 
 I Conocephalus, 67 
 I Conorrhinus sanguisugus, 146 
 Conotrachelus nenuphar, 196 
 Contact insecticides, 317 
 Control, insect, 315 
 Copris Carolina, 183 
 Coquillettia, 151 
 
 mimetica, 149, 151 
 
INDEX 
 
 341 
 
 Coreidse, 155 
 Corisa harrisii, 141 
 Corisidse, 141 
 Corizus, 158 
 
 crassicornis, 158 
 Corn delphacid, 103 
 
 -leaf aphis, 123 
 
 -root aphis, 123 
 
 worm, 191 
 Cornicles, 118 
 Corrodentia, 49, 81 
 CorydaUs cornuta, 165, 166 
 Cossidse, 210 
 Cotton boll weevil, 198 
 
 worm, 227 
 Crambidse, 214 
 Crambus, 214 
 Ctenocephalus canis, 290 
 Cucujidse, 177 
 Culex tseniorhynchus, 251 
 Culicidae, 248 
 Cultural methods, 322 
 Cut worms, 229 
 Cyclorhapha, 266 
 Cynipidae, 295 
 Cyrtophyllum concavum, 68 
 
 Dactylopiin-e, 131 
 Daddy-longlegs, 23 
 Damsel flies, 74 
 Danaidse, 245 
 
 Dasyneura leguminicola, 254 
 Datana, 224 
 
 ministra, 224 
 Delphacidse, 103 
 Deltocephalus inimicus, 111, 112 
 Dendroctonus, 205 
 
 valens, 203, 204 
 Dermacentor albipictus, 33 
 
 venusta, 32, 33 
 Dermanyssus avium, 28 
 
 gallinse, 29 
 Dermaptera, 49, 70 
 Dermestes lardarius, 178 
 Dermestidae, 178 
 Destructive leaf hopper, 113 
 Devastating locust, 60 
 Diabrotica, 191 
 
 longicornis, 191, 192 
 
 Diabrotica 12-punctata, 192, 193 
 
 vittata, 191 
 Diapheromera femorata, 58 
 Diaspinse, 134 
 Dicranbtropis maidis, 103 
 Digestive system of insects, 42 
 Dineutes americana, 174 
 Diplopoda, 18 
 Diptera, 50, 248 
 Direct methods for insect control, 
 
 315 
 j Dissosteira Carolina, 66 
 Dog-day cicada, 98 
 
 flea, 290 
 Dorycephalus platyrhynchus, 110, 
 
 111 
 Draeculacephala mollipes, 109 
 Dragon flies, 74 
 Drosophila, 287 
 Dytiscidae, 174 
 
 E 
 
 Earwigs, 49, 70 
 
 Economic entomology, 17, 302, 313 
 Ectobia germanica, 57 
 Eggs of insects, 45 
 Elateridae, 180 
 Ehn-leaf beetle, 192 
 Empoasca maU, 115 
 Endelomyia rosse, 293 
 Enemies, natural, of insects, 324 
 Engraver beetles, 203 
 Epeira scolopetaria, 24 
 Ephemerida, 49, 72 
 Ephestia kuehniella, 212 
 Eriocampoides limacina, 293 
 Euphorocera claripennis, 276 
 Euplexoptera, 70 
 Eurymus eurytheme, 243 
 I Euthrips pyri, 89, 90 
 Euvanessa antiopa, 247 
 Exclusion and restriction method of 
 
 insect control, 327 
 Eyes of insects, 39 
 
 Fall canker worm, 226 
 Field ants, 307 
 
342 
 
 INDEX 
 
 Fire fly, 182 
 Flat-headed borer, 181 
 Fleas, 289 
 Flesh flies, 286 
 Food habits of insects, 314 
 Forest flies, 288 
 Formicidffi, 305 
 Formicina, 305 
 Fruit-tree bark beetle, 205 
 Fiilgorida?, 101 
 
 Galerucella luteola, 194 
 Galleria mellonella, 213 
 Gall gnats, 253 
 Gamasidse, 28 
 Gastrophilus equi, 267, 268 
 
 ha^morrhoidalis, 270 
 
 nasalis, 270 
 Geometridse, 225 
 Giant water bug, 142 
 Gipsy moth, 232 
 Glassy-winged sharpshooter, 109 
 Glossary of terms, 329 
 Glossina morsitans, 283 
 
 palpalis, 283, 284 
 Gnats, 253 
 
 Grain aphis, spring, 123 
 Grape leaf hopper, 114 
 
 phylloxera, 129 
 Grapholitha interstinctana, 219 
 Grass thrips, 90 
 Green-bottle fly, 286 
 
 bug, 123 
 Ground beetles, 173 
 Gryllida?, 69 
 
 Grvllotalpa Columbia, 70 
 Gula, 40 
 Gyrinidse, 174 
 Gyropus, 84 
 
 H 
 
 Hackberry-gall psyllids, 116 
 Hajmatobia serrata, 279 
 Hsematopinus eurysternus, 161, 162 
 
 urius, 162 
 Handmaid moths, 224 
 Harlequin cabbage bug, 159 
 Harvestmen, 23 
 
 I Harvest mites, 26 
 i Hazel-nut weevil, 198 
 \ Head of insects, structure, 38 
 Heliophila unipuncta, 228 
 j Hellebore, 316 
 } Hemiptera, 49, 93 
 Hesperidai, 241 
 Hessian fly, 255 
 Heterometabolic, 48 
 Heteroptera, 93, 140 
 Hexapoda, 38 
 Hickory borer, 187 
 Hippoboscida^, 288 
 Hippodamia convergens, 176 
 Hog louse, 162, 163 
 Holometabolic, 48 
 Homalomyia brevis, 287 
 Homoptera, 93 
 Honey bee, 310 
 
 dew, 118 
 
 tubes, 118 
 Horn fly, 279 
 Hornet, 310 
 Horse bot flv, 268 
 
 flies, 265 
 
 louse, biting, 86 
 House centipede, 17 
 
 fly, 277, 278 
 Hydrobatidae, 144 
 Hydrophilidse, 174 
 Hylastinus obscurus, 201, 205 
 Hymenoptera, 50, 291 
 Hyphantria cunea, 235 
 Hypoderma bovis, 271 
 
 lineata, 270 
 
 Icerya purchasi, 132 
 Ichneumonidse, 295 
 Idiocerus alternatus, 108 
 Imago, 47 
 
 Indian meal moth, 211 
 Inimical leaf hopper. 111, 112 
 Insect control, 315 
 
 powder, 321 
 Insecticides, 315 
 Insects, relation, 312 
 
 structure, 38 
 Internal structure of insects, 42 
 iMdomyrmex humilis, 307 
 
INDEX 
 
 343 
 
 Ischnoptera, 55 
 
 pennsylvanica, 55 
 Isoptera, 49, 76 
 Isosoma tritici, 301, 302 
 Itch mite, 36 
 Ixodidse, 30 
 
 Jassid^, 111 
 Jassoidea, 105 
 June bugs, 183 
 
 Katydid, 68 
 
 Kerosene as an insecticide, 319 
 
 Kissing bug, 145 
 
 Labia minor, 71, 72 
 Labium, 40 
 Labrum, 40 
 Lace bugs, 150 
 Lachnosterna, 183 
 
 fusca, 183, 184 
 Ladybird beetles, 175 
 Lampyridse, 182 
 Larder beetle, 178 
 Larval period, 47 
 
 stage, 46 
 Lead arsenate as an insecticide, 316 
 Leaf beetles, 190 
 
 bugs, 150 
 
 rollers, 215 
 Leafhopper terms, 106 
 Lebia grandis, 173 
 Legs of insects, structure, 41 
 Lepidocyrtus purpureus, 53 
 Lepidoptera, 50, 206 
 Lepisma, 48 
 
 domestica, 51, 53 
 
 saccharina, 52, 54 
 Leptinotarsus decemlineatus, 190 
 Leptocoris trivittatus, 156, 157 
 Leptus americana, 27 
 
 irritans, 27 
 Leucania unipuncta, 227 
 Leucotermes flavipes, 76, 77, 81 
 
 Libellula pulchella, 75, 76 
 
 Lime-sulphur as an insecticide, 318 
 
 Limnogonus hesione, 145 
 
 Liotheidse, 84 
 
 Locustidae, 67 
 
 Locusts, 59 
 
 Locust-tree borer, 210 
 
 London purple as an insecticide, 
 
 316 
 Lucanidse, 182 
 Lucanus dama, 182 
 Lucilia csesar, 285 
 Luna moth, 240 
 Lyctidse, 178 
 
 Lyctus planicollis, 178, 179 
 Lygseidffi, 151 
 Lysiphlebus, 123 
 
 tritici, 296, 298 
 
 M 
 
 Machinery for the application of 
 
 insecticides, 322 
 Macrodactylus subspinosus, 184 
 Macrosiphum pisi, 121, 122 
 Mallophaga, 49, 83 
 Mandibles of insects, 40 
 Mantidse, 57 
 Mantispidse, 165 
 Maple scale, 133 
 Margaropus annulatus, 31 
 Masked bed-bug hunter, 146 
 Mating of insects, 45 
 Maxilla of insects, 40 
 May beetles, 183 " 
 
 fhes, 72 
 Mayetiola destructor, 255, 256 
 Meat fly, 286 
 Mecoptera, 50, 169 
 Mediterranean flour moth, 212 
 MegiUa maculata, 176 
 Melanoplus atlanis, 62, 65 
 
 femur-rubrum, 61, 62 
 
 spretus, 60 
 Melanotus communis, 180 
 MeUitia satyriniformis, 223 
 Melophagus ovinus, 288 
 Membracidse, 98 
 Menopon palUdum, 84 
 Mentum of insects, 40 
 Metamorphosis of insects, 47 
 
344 
 
 INDEX 
 
 Micropyle, 45 
 
 Mole cricket, 70 
 
 Monarch butterfly, 245 
 
 Monomera blatchleyi, 59 
 
 Mosquitoes, 248 
 
 Mouth structure of insects, 40 
 
 Mullein thrips, 92 
 
 nigra, 92 
 Murgantia histrionica, 159 
 Musca domestica, 277, 278 
 Muscidse, 277 
 Muscina stabulans, 283 
 Museum beetle, 179 
 MjTiopods, 17 
 Myrmeleonidse, 169 
 
 N 
 
 Nabid^, 147 
 
 Natural enemies of insectSj 324 
 
 Xecrophorus, 175 
 
 Nectaries, 118 
 
 Nepidse, 142 
 
 Nervous system of insects, 43 
 
 Neuroptera, 49, 165 
 
 Noctuidse, 226 
 
 Notolophus leucostigma, 230 
 
 Notonecta irrorata, 141 
 
 undulata, 141, 142 
 Notonectidse, 142 
 Nut weevils, 198 
 Nymphalidse, 247 
 
 O 
 
 Ocelli, 39 
 Odonata, 49, 74 
 (Ecanthus, 69 
 
 fasciatus, 69 
 
 niveus, 69 
 (Estridae, 267 
 (Estrus ovis, 275 
 Oncometopia undata, 109 
 Onion thrips, 90 
 Onycophora, 17 
 Ophion, 296 
 Orange dog, 242 
 
 white fly, 130 
 Oriental cockroach, 56 
 Ormenis pruinosa, 101 
 
 Orthezia solidaginis, 131, 132 
 Ortheziinae, 131 
 Orthoptera, 48, 54 
 Orthorapha, 248 
 Otioceras, 102 
 Owlet moths, 226 
 Ox bot fly, 270 
 Oyster-shell scale, 136 
 
 Pachypsylla celtidis-mamma, 116 
 
 Paleacrita vernata, 225 
 
 Palpus, 40 
 
 Panorpidse, 169 
 
 PapiHo cresphontes, 242 
 
 Papilionidae, 241 
 
 Paraglossa, 40 
 
 Parasita, 94, 160 
 
 Parasitica, 295 
 
 Parasitic insects, 324 
 
 Paris green as insecticide, 315 
 
 Parthenogenesis in aphids, 118 
 
 Passalus cornutus, 182 
 
 Pea aphis, 121, 122 
 
 weevil, 193 
 Peach-tree borer, 222 
 Pear slug, 293 
 
 thrips, 90 
 
 -tree psylla, 115, 116 
 Pedipalpi,' 23 
 Pentatomidse, 159 
 Periplaneta orientalis, 56 
 Perla, 49 
 
 Persian insect powder, 321 
 Phalangida, 23 
 Phasmidse, 58 
 Phasmomantis Carolina, 57 
 Philopteridae, 84 
 Phlegethontius 5-maculata, 206 
 Phloeothrips verbasci, 92 
 Phormia terrsenova, 284 
 Phorodon humuli, 119 
 Phylloxera, grape, 129 
 Phymatidse, 147 
 Phytonomus punctatus, 195 
 Pieridse, 242 
 Pieris rapse, 242 
 Pigeon tick, 30 
 Pilophorus, 151 
 Pimpla, 296 
 
INDEX 
 
 345 
 
 Pimpla conquisitor, 296, 297 
 Pissodes strobi, 200 
 Plant lice, 117 
 Platypsyllidse, 174 
 Plecoptera, 49, 72 
 Plodia interpunctella, 211 
 Plum curculio, 196 
 Podisus maculiventris, 159 
 Podura, 48 
 
 Porthetria dispar, 232 
 Praying mantis, 57 
 Predaceous bugs, 145 
 
 insects, 324 
 Principles of economic entomology, 
 
 312 
 Prionoxystus robinise, 210 
 Prionus, 185 
 Proctotrupidae, 296, 305 
 Proventriculus, 42 
 Pseudococcus citri, 131 
 Pseudoscorpionida, 23 
 Pseudova, 118 
 Psocidse, 81 
 Psoroptes communis, 34 
 
 var ovis, 35 
 Psyllidge, 115 
 
 Pteromalus puparum, 300, 301 
 Pterygota, 48, 54 
 Pulvinaria innumerabilis, 132, 133 
 Pupa stage of insects, 47 
 Pyralidge, 211 
 Pyralis farinalis, 211 
 Pyrethrum as an insecticide, 321 
 
 R 
 
 Ranatra americana, 143 
 Red spider, 25 
 Reduviidse, 145 
 Reduvius personatus, 146 
 Relation of insects, 312 
 Reproduction of insects, 44 
 Reproductive organs of insects, 
 
 44 
 Respiratory system of insects, 43 
 Restriction as a method of insect 
 
 control, 327 
 Rhagoletis pomonella, 287, 288 
 Rhyncophora, 195 
 Rocky Mt. locust, 60 
 Rose chafer, 184 
 
 Rose slug, 293 
 Round-headed borer. 
 Rove beetles, 175 
 
 187 
 
 San Jose scale, 137 
 Sanninoidea exitiosa, 222, 223 
 Saperda Candida, 187, 189 
 Sarcophagidae, 286 
 I Sarcoptes scabiei, 36 
 Sarcoptidae, 35 
 Saw-toothed beetle, 177, 178 
 Scale insects, 130 
 Scaraba^idse, 182 
 Schizoneura americana, 123 
 
 lanigera, 126 
 Scolytidse, 203 
 Scolytus rugulosus, 202, 205 
 Scorpionida, 22 
 Scorpion flies, 169 
 Scorpions, 22 
 Screw-worm fly, 277 
 Scutigera forceps, 20, 21 
 Sericophanes, 151 
 
 ocellatus, 150 
 Sesiidae, 222 
 
 Seventeen-year cicada, 95 
 Sharpshooter, 109 
 Sheep bot fly, 275 
 i scab mite, 35 
 I tick, 288 
 
 Short-nosed ox louse, 161 
 Shovel-nosed leaf hopper, 110, HI 
 Sialidaj, 165 
 Silk worm, 240 
 Silpha, 175 
 Silphidse, 175 
 Silvertop, 90 
 Simuliidai, 260 
 Simulium pecuarum, 261 
 Siphocoryne avense, 119 
 Siphonaptera, 50, 289 
 Six-spotted leaf hopper, 1 14 
 Skippers, 241 
 Smynthurus, 48 
 Snowy tree cricket, 69 
 Social wasps, 310 
 Sod worm, 214 
 Solpugida, 23 
 Southern buffalo gnat, 261 
 
346 
 
 INDEX 
 
 Special senses of insects, 44 
 Sphecina, 308 
 (Sphecius speciosus, 310 
 Spined soldier bug, 159 
 Spiracles, 42 
 Spotted-fever tick, 32 
 Spraying codling moth, 216 
 Spring grain aphis, 123 
 Spring tails, 48 
 Squash beetle, 191 
 
 bug, 155 
 
 -vine borer, 222 
 Stable fly, 282 
 Stag beetle, 182 
 Staphylinida^, 175 
 Stegomyia fasciata, 252 
 Sternorhynchi, 94, 115 
 Stink bugs, 159 
 Stomoxys calcitrans, 282 
 Stone crickets, 68 
 
 flies, 72 
 Structure of insects, 38 
 Submentum, 40 
 Sugar-cane hopper, 103 
 Swallowtail butterflies, 241 
 Sword bearers, 67 
 Sylvanus surinamensis, 177 
 Syrphidae, 266 
 
 TABANID.E, 265 
 
 Tabanus atratus, 266 
 Tachinidse, 275 
 Tarnished plant bug, 150 
 Tenderfoot leaf hopper, 109 
 Tent caterpillar, 235 
 Tenthredinidai, 292 
 Terebrantia, 88 
 Termites, 76 
 Termitidae, 76 
 Tetranychus bimaculatus, 25 
 
 gloveri, 26 
 Tettigoniellida, 108 
 Thalessa, 296 
 
 atrata, 295 
 
 lunator, 295 
 Thorax structure of insects, 41 
 Thread-legged bug, 147 
 Thripida?, 88 
 Thrips tabaci, 90 
 
 Thrips tritici, 89 
 
 Thyridopteryx ephemera^formis, 
 
 207, 209 
 Thysanoptera, 49, 87 
 Thysanura, 48, 52 
 Tibicen septendecim, 94, 95 
 Tick, cattle, 31 
 
 spotted fever, 31 
 Ticks, 30 
 Tiger beetles, 173 
 Tinea pellionella, 221 
 Tineidai, 221 
 Tineola biselliella, 222 
 Tingitidse, 150 
 Tobacco extract, 320 
 Tomato- worm larva, 206 
 Tortricida?, 215 
 
 Toxoptera graminum, 122, 123 
 Trachea of insects, 43 
 Transformations of insects, 45 
 Tree crickets, 69 
 
 -hoppers, 98 
 Tremex columba, 294 
 Trichodectes, 84 
 
 parumpilosus, 86 
 
 scalaris, 85 
 Trichoptera, 50, 170 
 Trimerotropis maritima, 64, 65 
 Trombidiida?, 26 
 Tsetse flies, 283 
 Tussock moths, 230 
 Typhlocyba comes, 114 
 Typhlocybidae, 114 
 
 Unity of habit of insect groups, 314 
 Uroceridse, 293 
 
 Vedalia, 177 
 cardinalis, 132 
 
 Vespa germanica, 310 
 maculata, 310 
 
 Vespidae, 310 
 
 Viceroy butterfly, 247 
 
INDEX 
 
 347 
 
 W 
 
 Walking-stick, 58 
 Wasps, 308 
 Water beetles, 174 
 
 boatmen, 141 
 
 bugs, 142 
 
 scorpions, 142 
 
 striders, 144 
 Web-worm moths, 234 
 Wheel bug, 146 
 Whip scorpion, 23 
 Whirligig beetles, 174 
 White ants, 76 
 
 fly, 130 
 
 -marked tussock moth, 230 
 
 pine weevil, 200, 203 
 
 Willow saw fly, 292 
 
 scale, 135 
 Wings, structure of insects', 41 
 Wire worm, 180 
 Wood borers, 185 
 Woolly aphis, 126 
 
 Yellow-fever mosquito, 252 
 Yellow jacket, 310 
 
 Zaitha fluminea, 141