ISF 593 T5 H8 iCopy 1 U. S. DEPARTMENT OF AGRICULTURI^ BUREAU OF ENTOMOLOGY— BULLETIN No. 72. L. 0. HOWARD, Entomologist and Chief of Bureau. INFORMATION CONCERNING THE NORTH AMERICAN FEVER TICK, WITH NOTES ON OTHER SPECIES. r.Y w. I). hitntp:r and av. a. hooker. Issued Novembeb 2, 1907. WASHINGTON: GOVERNMENT PRINTING OFFI(!E. 1907. aass_^S„FLs9^ Book 3jl±1_2 'i/-. U. S. DEPARTMENT OF AGRICULTURE, BUREAU OF ENTOMOLOGY- BULLETIN No. 72. L. O. HOWARD, Entomologist and Chief of Bureau. fl INFORMATION CONCERNING THE NORTH AMERICAN FEVER TKUv, WITH NOTES ON OTHER SPECIES. BY W. D. HUNTER ani> W. A. HOOKER. Issued Novembee 2, 1907. WASHINGTON: GOVERNMENT PRINTING OFFICE. 1 \) 7 . A BUREAU OF EA^TOMOLOar. L. (). HowARij, Eniomologist and Chief of Bureau . C. L. Marlatt, Eniomologist and Acting Chief in absence of Chief. R. S. Cliftox, Chief Clerk. F. H. Chittenden', in charge of breeding cxperivicnts. A. D. HoPKixs, in charge of forest insect investigations. W. D. Hunter, in charge of cotton boll xveevil invest igat ion ,s. F. M. Webster, in charge of cereal and forage plant insect irnestigatio7}s. A. L. Quaintance, in charge of deciduous fruit insect invent igntions. E. F. Phillips, in charge of aviculture. D. M. Rogers, in charge of gipsy moth and brown-tail moth imrk. A. W. Morrill, engaged in while fly investigations. W. F. Fiske, in charge of gipsy moth laboratory. W. A. Hooker, engaged in cattle tick life history itirestigationti. A. C. Morgan, engaged in tobacco insect investigations. R. S. WoGLUM, engaged in hydrocyanic acid gas investigations. C. J. GiLLiss, engaged in silk investigations. R. P. Currie, assistant in charge of editorial work. Mabel Colcord, librarian. MAR 31 19C.3 ,D. ot D. LHTTHR OF TRANSMITTAL. I'. S. Depahtafext of Agkicultihk, Bureau of Eintomolocjv, WasMngion, I). C, June 19, 1.907. Sir: I have the honor to transmit herewith a manuscript prei)ared by jNIessrs. W. D. Hunter and W. A. Hooker of this Bureau. The manuscript is a study of the hfe history and habits of the North Amer- ican fever tick, tog-ether with notes on other species. The work upon which this bulletin is based was begun in July, 1905, after practically all of the directors of the southern experiment stations had brought to the attention of this Bureau the necessity of additional work on the important parasite which transmits Texas or splenetic fever of cattle. Prof. H. A. Morgan, director of the Tennessee Experiment Station, has given valuable advice during the progress of the work. The paper contains information of great value in the practical work of tick eradication. I therefore recommend that it be issued as Bulletin No. 72 of this Bureau. Respectfully, C. L. .Marlatt, Acting Chief of Bureau. Hon. James Wilsoa, Secretary of Agriculture. C()\T]-:\TS ('()N(;kknin(; tiik north amkhican kkvkr tick. Puice. Inlroduclory 9 occasioned by the calllc I ick 11 The life history of ticks in general j 2 The life history of the cattle tick j 3 Period previous to oviposition 14 Oviposition period J4 Egg stage 15 Incubation 17 Relation of temperature to incubaiinn 19 Effect of heat and cold on eggs 21 Submergence of eggs in water 22 Percentage of eggs hatching 23 Larval or seed-tick stage 2o Nonparasitic period [ _ 23 Effect of water on seed ticks 24 Longevity of seed ticks 25 Parasitic; period 27 Development on liost 28 Adidt stage 30 Effect of continuous cold and lieat on engorge(l fenudes 31 Effect of direct sunlight on adults 32 Effect of submergence in water on engorged adult licks 3,2 Dropping from host 33 Locomotion " 33 Host relations of the cattle t ick 34 Relation between ration and tick infestat ion 35 Enemies of ticks 3(; The practical application of llie information recorded in this bullelin 37 X(rrK.S ON VARIOUS SPECIES OF Tl( KS FO I XD l\ IIIF: I \ FP K I > STA'J'KS. Classification and habits of ticks 40 Key to families. sul)families, and .\ortli American genera of ticks (Ixodoidea) 40 Family Argasidse 41 Genus Argas 42 Genus Ornithodoros _ 45 Family Ixodidse 40 Subfamily Rhipicephalina' 47 Genus Rhipicephalus 47 Genus Margaropus 49 Genus Dermacentor 49 Genus Haemapliysalis 52 Subfamily Ixodinye 54 Genus Ixodes ' 54 Genus Amblyomnia 58 Bibliography (;4 Index 77 ILLUSTRATIONS PLATES. Page. Pi,ATK T. Tlie North American fever tick. Fig. 1. — Eggs of the tick, Marga- ropus annulatus, deijosited under stable litter. Fig. 2. — Seed ticks of Margaropus bunched on grass and stake IG II. The North American fever tick. Fig. 1. — Steer used in experimental work. Fig. 2. — Arrangement for obtaining data on incubation .. . 16 III. The North American fever tick and other species. Fig. 1. — Marga- ropus annulatus, male. Fig. 2. — Hsemaphysalis leporis-palustris, female. Fig. 3. — Stigmal plate of Margaropus annulatus, male. Fig. 4. — Mouth parts of Ixodes cookei. Fig. 5. — Stigmal plate of Rhipicephalus sp., male. Fig. G.— Stigmal plate of Ambhjomma maculatum, female 48 IV. Stigmal plates of ticks. Fig. I.— Stigmal plates and anus of Dcrma- rentornitens,msde. Fig. 2.— Stigmal plate of same. Fig. 3.— Stig- mal plate of Amblyomma cajennense, male. Fig. 4. — Same, female. Fig. 5. — Stigmal plate of Dermacentor variabilis, female. Fig. G. — Stigmal plate of Dermacentor occidentalis 48 TEXT FIGURES. Fig. 1. Margaropus microplus: Genital apparatus 14 2. Graphic table for the separation of the families and genera of licks 41 :'.. Rhl pi(( phnlus sp. : Capitulum of female 47 4. Uliipiri jihiilus sp. : Coxae of male and female 48 5. D( nitutxutor nitens: Capitulum of female 52 6. Dermacentor nitens: Coxge of male and female 52 7. Hsemaphysalis leporis-palustris: Capitulum and scutum of female 53 8. Hxmaphysalis leporis-palustris: Coxse of male anrl female 53 9. Amblyomma cajennense: Mouth parts of male 60 10. Amblyomma cajennense: Coxse of male and female 61 11. Amblyomma maculatum: Mouth parts of female 62 12. Amblyomma maculatum: Coxiv of male and female 63 13. Amblyomma maculatum: Scutum of female 63 7 INFORMATION CONCERNING THE NORTH AMERICAN FEVER TICK, WITH NOTES ON OTHER SPECIES. INTRODUCTORY. It is safe to state that no more important pi'ohleiii than the eradi- cation of the cattle tick (Margaropus '^ annulatus Say) confronts the farmers of any country. Not only the cattle-raising' industry, but the whole economic condition of a large section of coiuitry is affected. The tick, without unv but the most limited power of locomotion, and for all practical purposes dependent upon cattle for its (Existence and dissemination, presents a problem in eradication of a hopel'ul nature. Cattle are under the control of man. Therefore, the ])rot)- lem is quite different from that involved with other ])ests, like tlu^ boll weevil, which by flight spread over large areas of land. In the one case absolute eradication is possible and in the other it is out of the question. In fact the })()ssibility of the total extermination of the tick in this country is by no means visionary. It was foreseen originally, probably, by Dr. Cooper Curtice, who wrote as follows in 1896: "I look most eagerly for the cleansing of even a certain portion of the infected territor}^ under the direct intention of man, for it opens the way to pushing the tick back to the S})anish Isles and Mexico, and hberating cattle from disease and pests and the farmer from untold money losses. Let your war cry l)e, ])eath to the ticks." '' In view of these facts it is evident that the most complete knowl- edge of the habits and life history of the tick is of the utmost impor- tance. All means of eradication must depend upon such knowledge, and improvements in present methods must depend upon additional information regarding the tick. Dr. Cooper Curtice, who will be quoted frequently, because he has been among the foremost in the study of the problem, has written as follows: ''To the scientist studying the tick to learn its life histor^^, habits, form, and anatomy, "Neumann has shown tliat the generic name Boophilus of Curtice must, in ol)e(li- ence to the zooloo;ical law of priority, fall as a synonym of ihc earlier naiiip, Marga- ropus of Karsch. ^Journ. Comp. Med. and Vet. Archives, Vol. XVll, p. G.%. 10 NORTH AMERICAN FEVER TICK AND OTHER SPECIES. the fact that these animals are pests to the stockman throughout the greater part of the year is of very httle importance, while the latter cares little about such matters if he can only learn how to rid his cattle of them. Yet it is only by learning the life liistory that remedies to prevent them can be applied intelligently, and the fact that the knowledge attained is of practical value adds a double interest to their study." "^ In view of the evident importance of the work it is surprising that so little has been done in this country. In 1892, about a jenr pre- vious to the issuance of Smith and Kilborne's epoch-making bulletin demonstrating the tick transmission of fever, Dr. Cooper Curtice })ublished the first data regarding the life history of the cattle tick as Bulletin 24 of the Texas Agricultural Experiment Station. It was accompanied by excellent illustrations. The value of this work will be understood from the fact that it was of a pioneer character, and that all subsequent work has depended upon it. Nevertheless, it was of a preliminary nature and merely outlined matters that must eventually receive the most careful investigations. Prof. H. A. Morgan, principally in bulletins 51 and 56 of the Louis- iana Experiment Station, has added greatly to our knowledge of the cattle tick as well as other species. His work has such practical bearings that it has been the chief indication of the value of life- history studies in pointing out successful methods of eradication. Recently Messrs. Wilmon Newell and M. S. Dougherty, of the Louis- iana crop-pest commission, have published a valuable contribution which still further shows how every fact relating to the tick can be utilized in combating it. The above are the ijrincipai publications by American workers. There are many others which also contribute important facts. Among these are Connaway's, Schroeder and Cotton's, Ransom's, and others. In other countries excellent work has been done on related forms. In South Africa Prof. C. P. Lounsbury has macle scholarly studies of Afargaropus {Boopliilus) dexoloratus and many other species. In Argentina, Dr. F. Lahille has recently published the results of some of the most exhaustive work on ticks that has been done. These works, with others, are listed in the bibliography at the end of this bulletin. Notwithstanding the studies that have been conducted in this country, it must be stated that our knowledge of the tick is far short of what it shoidd be. There is a lack of knowledge of local variations, due to climatic influences, as well as such matters as dissemination. To supply this tleficiency, the Bureau of Entomology, in cooperation with the officers of several experiment stations, has undertaken a 'I Tex. Agr. Kxp. Sla. Hul. 24, p. 238. LOSSES OCOASIONKD BY CATTLE TICK. 1 1 careful study of the tick. Some of the results of practical bearino- are given in the following pages and others will be published from time to time. The writers desire to express their thanks to Prof. H. A. Morgan, director of the Tennessee Agricultural Experiment Station, for many most valuable and courteous suggestions in the course of this work. He has turned over to the wTiters many of his original notes and lias generously assisted in numerous other ways. LOSSES OCCASIONED BY THE CATTLE TICK. Undoubtedly the poi)ular idea of the damage caused by the cattle tick concerns itself with the actual death of cattle from the disease transmitted by the tick. Although this is a very important matter and would fully justify the most energetic attempts toward the eradication of the tick, it is really unimportant in comparison with the other losses. Mr. August Mayer, a practical' cattle breeder of Shreveport, La., and Dr. J. R. Mohler, of the Bureau of Animal Industry of tins Department, have made most careful, comprehensive estimates of the losses caused by ticks. The following summary is taken largely from their writings: 1. Loss by death from disease in young animals and those removed from temporarily tick-free localities (as, for instance, in cities) to places where they become infested. The enormous loss under this heading will be understood when it is recalled that every bovine animal in the tick area must suffer an attack of fever if it becomes infested with ticks. In an instance that came to the attention of the writers, 39 out of 40 calves dropped in a city died of tick fever when removed to an infested pasture. 2. Loss in weakened condition and stunted growth caused by the fever. 3. Loss by gross tick infestation. At the present time (March, 1907) hundreds of cattle in south Texas are dying from gross infesta- tion resulting from a mild winter. In extreme cases, Mr. Mayer estimates that as many as 200 pounds of blood may be withdrawn from the host during a single season. This makes a gain in weight impossible even in the best of pastures. Moreover, Prof. H. A. Morgan and other observers believe that gross infestation and the consequent general debility induce acute attack of fever even in animals ordinarily immune. 4. The tick makes hazardous the importation of pure-bred cattle. This prevents the upbuilding of southern cattle and at the same time largely deprives the northern breeder of a market that he should have. Moreover, the inability of the southern breeder to exhibit his stock in 12 NORTH AMKKIOAX FEVER TICK AND OTHER SPECIES. the north and of the northern breedei- to exhibit his in llie tick ai-ea is a handicap, the importance of which will be readily seen. 5. The necessary restrictions in the shipping- of southej-n cattle also handicap the breeder and affect the price. 6. The maintenance of the cjuarantine involves c-onsiderable annual expense for the protection of the cattle owners north of the line. 7. Minor losses may be grouped as follows : (a) In Texas, especially, the tick induces the attack of the screw- worm fly (Chrysomyia macel- laria Fab.); (h) there seems to be, as pointed out by Mr. Mayer, a considerable interf^^rence with the fecundity of infested cows; (c) the railroads are put to the expense of disinfecting cars and maintaining separate pens and the stockman to the expense of dipping — items which react on the price that southern cattle bring. All the losses that have been mentioned total a])])roximately $100,()()0,0()() each year. At jn'esent the loss, as indicated by Doctor ISIohler, amounts annually to at least 10 per cent of the value of the cattle. The (|uality of tlie animals is the lowest and the loss is greatest in the regions wIkm'c the natural conditions without the tick should ])roduce the iinest cattle ^\ith the least loss. But the damage may be better expressed by the stat(Mii(Mit that the tick makes profitable ])roduction practically im])()ssil)le in the South. Any successful system of agriculture nnist rest uj)on a diversification of crops, and this, in turn, depends upon animal husbandry to maintain the fertility of the soil. Therefore, until the tick is (U'adicated oi' j)laced under control, a rational .system of agriculture in the infested area is out of the ({uestion, and that achievement would mean almost as much to the North as to the South. THE LIFE HISTORY OF TICKS IN GENERAL. The following genei'al statement I'egai-ding the life liistoiy of ticks is taken fi'om Salmon and Stiles:" Ticks arc temporary parasites, attacking inamiuals. birds, and reptiles. Tliey do not appear to be so strictly confined to ('(nlain hosts as do parasites in general. Still, this may be more of an apparent than a real rnle. Certain it is that, although a given tick may he found occasionally on aTiiinals which are very dissimilar (dog ticks have, for instance, been found on snakes), still the ^arious s^peeies show a decided predilec- tion for certain hosts. The parasites copidate during the i)eriod of parasitism '' and suck the blood from their hosts. The female grows to a large size and eventually drops to the ground and « Seventeenth Ann. Rej)t. Bureau of Animal Industry, U. S. Dept. Agric, p. 398. ''This is not invariable. Arnhhjomnia aincrkanum scjmetimes copulates soon after the second molt, but f)efore it has gained a lio.st. It is likely that other sj)ecie.s also occasionally do so.— \V. D. H. and W. A. 11. LIFE HISTORY OF CATTLE TICK. 13 lays numerous eggs, which are usually more (h- less clustered together. The larva upon hatchhag possesses three pairs of legs, the fourtli pair being added. during I he first molt. Either the hexapod or the ortnpod form may allack its host. From the foregoing it will he seen that the eatth^ tick, lik(> other- ticks, passes thi'ough tlie following stages: Egg, larva (six-legged form), nymph, and adult. The eggs are nearly ronnd, dark hrown in color, and (h^posited in largo masses, held together hy the gtmnny secretion with wliich the female coats each egg as it is (le])osited. The next stage, known as the seed tick, differs remarkably from the later stages in the fact that six instead of eight legs are present. The stigmata are located be- tween the second and third coxa>, just anterior to the third coxa-, and problematic indications are seen between the first and second coxa\ No distinct genital or anal opening can be seen in this stage. The anterior legs are much larger than the others. They are waved violently tlu-ough the air when the seed ticks are distiu'bed either l)y the approach of a host or in any other way. After some time th(> seed tick molts and the next, or n^nnphal stage, is provided with eight legs. The absence of the genital opening will differentiate this stage from the following one. Ticks in the nymphal stage are frequently referred to in the South as "yearling ticks." After a second molt the adult form is reached. Copulation then takes place, and after engorgement the female drops to the ground for the purjjose of depos- iting eggs. THE LIFE HISTORY OF THE CATTLE TICK. As })ointed out by Morgan the most important fact about the (lattle tick {Margaropus annulatus Say), from the stand})oint of ])ractical control, is that the time of development on the animal is always shorter than the total of the preoviposition, oviposition, and incubation periods. This gives the farmer an opportunity to free his cattle ajid pastures of ticks l)}^ the same process of rotation. As a foundation for the surest and most economical procedure an a{;curate knowledge of the variations of the periods in the life history of the tick under different conditions is absolutel}" essential. Our effort in this bidletin is in a measure to supply this information. The work has been prin- cipalh" to obtain data necessary in the pasture eradication and feed- lot systems of eradication. We have consequently studied the devel- opment of the tick both during its existence on the animal, by means of a steer procured for that purpose, and during its life, under various conditions, when not attached to the host. 14 NUKTH AMERICAN FEVER TICK AND OTHER SPECIES. PERIOD PREVIOUS TO OVIPOSITION. The cattle tick, like other species, passes tln'ough a distinct i)eri()cl between the time of dropping from the host and the beginning- of ovi- position. When the tick drops, the eggs are not ready to be depos- ited, but must pass from the ovary through the oviduct. (See fig. 1.) Thus there is a definite physiological basis for a period which has a very practical l)(>aring on ])lans of eradication that depend upon a knowledge of the exact time to be allowed in removing cattle fi'om one inclosure to another. Lahille has used the term "prootoquie" for this period, but we shall refer to it merely as the preovipo- sition period. As will be seen from Table I the preoviposition period ranges from 2 to 40 days, depending upon tempera- ture. In the summer it averages between o and 4 days, and in winter over 20 days. It might be supposed that the data in the table referred to show a preoviposition pe- riod longer than normal on „,,.,, . , ., . account of the removal of Ju;. ].-l.enital apparatus of Margaroimf: mtcroplus: a, Position of eggs at time of dropping of tick from host; the tlcks artificially. HoW- b. position of eggs when oviposition begins. Uighly ever, oulv ticks about tO drop magnifipa (redrawn from Lahille). ' ^ ^\ere selected, and repeated tests with ticks actually dropped sIiowcmI that the method followed gives the natural preoviposition period. OVIPOSITION PERIOD. As will be seen from Table 1, the j)eriod occupied in oviposition ranges from 6 to 70 da^'s, depending upon the temperature. In the summer it averages 10 or 11 days, while in the winter it is two or three times as long. « LIFE HISTORY OF CATTLE TICK. 15 Table I. -Oviposition of Margaropus annulatus. July, 1905, to July, 1906, at Dallas, Tex. When collected. 1905. July 21.... Aug. 3 Sept. 18... Sept. 27... Oct. 12.... Nov. (■) Dec. f) 1900. Feb. 6 Feb. 21.... Mar. 23.... Apr. 6 Apr. 20.... May 4 May 22.... June 5 Juie20 July2 July 13.... To'^al... Averssp- Preoviposition period. Days. 3 Days. 2 3 3 3 4 10 21 Days 2.9 3.5 3.4 3.0 5.1 11.9 28.6 Oviposition period. Days. 13 11 18 19 44 04 70 [^^ Days 6 7 12 19 21 21 20 Days. 8.2 9.0 15.0 19.0 30.7 39.9 42.0 23.4 21.8 15.6 14.6 12.6 10.9 11.7 11.0 10.4 Period from drop- ping to end of ovi- position. Days. 14 13 20 21 48 79 Days. 8 U 14 21 21 33 Days 11.0 11.8 17.0 21.0 32.0 .50.8 71.0 .50.5 47.8 30.2 25.7 20.0 21.4 16.4 13.4 14.2 13.9 12.5 Number of eggs per tick. Eggs. 3,800 2,228 3, 875 2,311 2.689 3,946 2,134 3,496 2,437 2,260 3,412 2,070 3,180 2,881 2,407 2,292 2,397 515 1,460 147 10 1,118 1,281 2,197 1,701 1,391 152 843 1,135 1,060 Eggs. 1,185 1,971 1,779 2,009 1,941 1,058 2,891 2,251 2,2.50 1,802 1.950 1,837 2.068 32, 499 1,911.7 From Table I the following important, practical data are obtained: 1. The preoviposition period ranges from about 3 days in summer to as many as 28 days in winter. 2. The oviposition period ranges from between 8 and 9 days in summer to 42 days in winter. 3. The total period from dropping to the end of oviposition ranges from 11 days in summer to 71 days in winter. It should be noted that Table I gives the total period from drop- ping to the end of oviposition based upon the weighted averages of the preoviposition and the oviposition periods. Therefore the maximum total period may be somewhat longer than indicated, as, for instance, in cases where either the preoviposition of the oviposi- tion for some reason are prolonged beyond the average. EGG STAGE. The eggs are generally elliptical, but vary in shape on account of pressure and drying. In color thej are at first honey-yellow, but soon change to a deep yellowish brown. They are shiny and smooth. The average size in a lot of 10, measured by a micrometer^ was 0.54 by 0.42 mm. About the middle of the incubation period in many species a whitish spot appears on the eggs and becomes more conspicuous as the time for hatching approaches. This spot is 16 NORTH AMERICAN FEVER TICK AND OTHER SPECIES. located toward one end and seems to be due to the excretion of the embryo. In Margaropus anmdatus it is very conspicuous and is a certain indication of viabihty. The act of oviposition is most interesting. This process was referred to by Dr. Cooper C^n^tice." An analogous operation in Ixodes ricinushns recently been carefully described and illustrated by \^aieler/' and was earlier noted by Lewis.'' One of our asso- ciates, Mr. R. A. Cushman, has observed the operation. The follow- ing description is l)ased upon his notes : When oviposition is about to take place the capitulum is bent downward toward the genital aperture. This exposes a delicate, viscid membrane betwecMi the capitulum and the scutum. The membrane becomes distended and is projected out over the capitu- lum in two round.Ml l<>b(^s. practically covering it. This process is repeated several tiim>s b<>fore the (^o-g is finally ejected, the mem- brane being extruded and ivti-acted alternately while the capitulum is lowered and rais(Ml. Finally tlu^ white, membranous ovipositor is exten.led, turning inside out. until it touches the distended mem- brane. T1h> capituhun is new completely hidden. As soon as the ovipositor and membrane have come in contact the former slowly recedes, heaving the (>gg adhering to and partially enveloped by the ineml)rane. The egg riMuains in this i)()sition for a varying length of time. Then the membrane is withdrawn, rolling the egg along for a short distance on the dorsal surface of the capitulum. At the same time the ca])itulum is raised. Then the ])rocesses of distention and contraction of the membr:uie and lowering and raising of the capitu- lum aiv repeated s(>v(n-al times, the egg Ijeing finally completely coated by the viscid substance from the membrane and being finally pushed i)ack and d(>i)osited on \]\v anterior edge of the scutum. p:ach egg is laid in this manner, the tick backing slowly away and leavingMlie mass of eggs in front of her. The actual time consumed by the tick in laying a single egg is about 80 seconds, w^hile the removal of the egg and the resting period consume from one to sev- eral minutes, a much longer resting i)eriod being taken at intervals between lots of from 10 to 50 eggs. It has been impossible for us wdth the means at our command to demonstrate the ''paired, race- mose glands" of the membranous sac referred to by Curtice. As far as we have been able to s(>e, tho substance with which the eggs are coated is secreted from numerous minute glands scattered over the surface. "Tex. Agr. Exp. Sta., Bui. 24, p. 242. ?>.Tourn. Agric. Sci., 1906, p. 405. cProc. Rov. Mici-os. Soc, 1892. 3logy, U. S^ Dept. of Agriculture. Plate I. Jul. 72, Bureau of Entomology, U, S, Dept. of Agncultun Plate II. LIFE HISTORY OF CATTLE TICK. 17 In the manner described a mass of eggs grows steadily in front of the tick, while its body becomes correspondingly smaller as the process proceeds. The gummy secretion holds the eggs together so that the mass looks not unlike a large accunudation of minute brown beads. The number of eggs deposited varies greatly with the size of the female. The highest number recorded in our experiments was 3,806." The average of 189 ticks under various conditions was 1911.7, and this probably very closely approximates the average under natural conditions. The daily average, of course, varies also. The maxi- mum is generally reached from 7 to 9 days after deposition begins. The highest number for any 24-liour period was 826. The average for 20 ticks was 144. INCUBATION. Most important means of control of the cattle tick depend upon taking advantage of the fact that eggs remain on the ground for a considerable time before hatching. Provided there are no seed ticks present, it is perfectly safe to allow cattle in areas in which ticks may be dropped from them, as, for instance, in fields under cultivation for one crop season, if the animals are removed before hatching takes place. It will be seen that this has an important bearing on the process of relieving cattle of ticks by placing them for limited periods in different tick-free inclosures. Accordingly we have made an especial effort to obtain data regarding the period occupied in incu- bation under different conditions and in different seasons. In 1905 a number of experiments to determine the length of the incubation period were conducted, the eggs being placed in paper pill boxes. Subsequent work showed that this arrangement gives more rapid development of the embryo than takes place under normal conditions. Especially is the period shortened when an abundance d in July hatched in from 22 to 2(5 days. Eggs depositt'd in August liatchcd in from 23 to 32 days. In September eggs deposited prior to the 18th hatched in from 23 to 76 days. Eggs deposited after September 18 have not hatched up to February 20, with but two exceptions. These were eggs deposited October 3 and October 7, wliicli began to hatch on February 18. These eggs were placed in such a way that they were more exposed to the sun than other lots that have not hatched, deposited before and since the dates mentioned. LIFE HISTORY OF CATTLE TICK. 19 Table II. — Period of incubation of Margaropua nnnulnlii)t at Dnllns, Tex., 1906. under various conditions. iCggs (Ipposited. Apr. 13. Apr. 14. .\pr. 1.2. -\pr. 2/ . May 13. May l.T . May 28. May 3iJ. May 31 . June 9.. .June li». June 1 1 . June 21 . June 22. June 24 . June 24 . June 30. July 1 . . July 20. July 20. July 22. Julv 31 . July 31 . July 31. Aug. 1 1 . Aug. 12. Ilatdiing. Minimum | iiu-ubation i{ Kggs dcii period. ; June o . . May 30. May 31.. June 4.. June 14. June 12. J une 23 . June 26. June 27. Julys.. July 5.. July 7.. July IK., July 14.. July 16.. July 16.. July 20. July 22.. Aug. 10. Aug. 14. Aug. 14. Aug. 22. Aug. 22. Aug. 23. Sept. 4. . Sept. 3.- Days. a 29 127 128 "28 127 "26 127 128 ''23 123 ''23 ''21 122 ''22 126 C24 ''23 C23 124 ''25 Aug. Aug. Aug. Aug. Aug. Aug. Aug. Aug. Aug. Aug. Aug. Aug. Sept. Sept. Sept. Sept. Sept. Sept. Sept. Sept. Sept. Sept. Sept. Sept. Sept. Sept. 8. . Sept. 6.. Sept. 9.. Sept. 18. Sept. 10. Sept. 11. Sept. 13. Sept. 14. Sept. 10. Sept. 20. Sept. 21. Sept. 23. Sept. 23. Sept. 24. Sept. 27. Sept. 26. Oct. 7... Oct. 10.. Oct. 15 . . Oct. 24.. Oct. 26.. Nov. 5.. Dec. 2... Dec. 2... Feb. 20.. Minimum incubation period. Day.'i i2S ''24 ''23 132 ''23 f24 123 C24 ''24 ''24 C25 127 C23 6 24 127 -^25 C29 ft 32 137 c41 ''43 153 ''76 i76 ''148 1 The eggs were placed in open-bottom test tubes in sand in the open air. They were protected from the direct rays of the sun at all times by a cheese-cloth screen, fp to 11 a. m. they were within the shade of the house. '' In open-bottom test tubes in soil exposed to sun at all times. c In open pill boxes outdoors protected from sun and rain at all times. RELATION OF TEMPERATITRE TO INCUBATION. In th(^ series of experinieuts just referred tt) accurate data on tem- perature were obtained. Standard maximum and minimum ther- mometers kept in an instrument shelter were used. In Table III the records of temperatures are given together with the average incubation periods for the various lots of eggs imder observation during different months. The data show that there is an intimate relation between temperature and the period of incubation. The shortest average minimum incubation period (23.4 days) occurred when the average temperature was liighest (80.2° F.). The longest average minimum incubation period (137 days) occurred with the lowest average mean temperature (53.2° F.)., Between these ex- tremes there is a graduated correspondence between temjierature and incubation. 20 NORTH AMKRI(;AN FEVER TICK AND OTHER SPECIES. Table III. — Relation of tcniperaturr to period of inriibntion in Margaropiis annulatu^ at Dallas. Te.r.. 1905-1906. Month erceptible mortality among them. I.ONCJEVrPY OK SEED TICKS. The time that seed ticks may survive without a host is a most important matter in plans for control. Our experiments on this point have been of two kinds— (1 ) with seed ticks from eggs deposited by females placed on the ground in favorable circumstances, thus giving absolutely natural conditions, and (2) with seed ticks in glass tubes, where they could be observed more closely. In the first .series, which w^as instituted at the suggestion of Pro- fessor Morgan, several hundred engorged ticks wwo |)lace(l on tl;e ground at regular intervals. The only inclosure was a cylinder of 2-inch-mesh wire screen about 4 feet in diaineter to pr-event (hsturb- ance. The seed ticks from females placed under tiiese conchtions accumulated in enormous numbers on the blades of grass or stakes provided for the purpose (see PI. I, fig. 2). Table V gives the num- ber of days the seed ticks survived in these experiments, together with other data. It wall be seen that the shortest period w^as 49 days and the longest 159+ days. However, the important period is from the time of dropping of the adults to the death of the resulting seed ticks, since the farmer must always suppose in rotating his cat- tle that adults were dropped on the day of removal from the pasture which it is desired to clean. This period ranged from 91 to 175 + days. It will be noted that there is considerable variation in the period of survival, even at the same season of the year. This seems to depend upon two factors, namely, the number of seed ticks in the bunches and the amount of rainfall. The larger masses survive longer, perhaps because the moisture is better retained, and heavy rains scatter and reduce the masses. It is probable, on account of the very large numbers of seed ticks in our experiments, that the periods given in the tables are somewhat longer than normally occur in the field. How^ever, such excessive numbers do sometimes occur in nature. For instance, wdien an animal dies of gross infestation thousands of ticks deposit in a very restricted area. Mr. J. D. ^litchell has seen cases of this kind in which the bunches of seed ticks were fully as numerous as in our experiments. t>(; NUKTH AMERICAN FEVER TICK AND OTHER SPECIES. Table V. — Longevity of seed ticks of Margaropus annulatus Say, at Dallas, Tex., 1906. When dropped. Period from dropping to oompletion of ovi- position. When hatched. Seed ticks all dead. Maximum period from drop- ping to death of all seed ticks. Period of life of seed ticks. Minimum. Maximimi. June 20 Days. 12 12 14 S Days. 18 18 21 19 10 16 Aug. 12... Aug. 15... Julys Aug. 14... Sept. 1.... Sept. 14... Oct. 8 Oct. 21. . . . Oct. 20. . . . Oct. 15.... Oct. 20. . . . Days. 110 120 154 80 91 17.")+ Days. June 23 a 67 May 19 107 Do.. Aug. (i 49 1.59+ a In this experiment the seed ticks wore accidentally disturbed. They would have lived some days beyond the period indicated. i Some alive Feb. 20. 1907. Ill the second series t)f experiments to tleterniiiie the longevity of seed ticks the eggs were placed in glass tubes with open bottoms. As will be seen from the footnotes to Table VI certain seed ticks in tubes were shaded at all times, others in tubes were exposed con- stantly to the sun. while the remainder were placed in pill boxes protected from sun and ruin. It is supposed that these diverse^ con- ditions give an av(M-age lengtii of survival that approaches closeh" to that occurring under natural conditions. The detailed results follow: Tahm-; YI. — Longirily of .sc(d ticks of Margaropus armnlalus Say, Dallas, Tcr., I'KiG. Eggs deposited.' Hatching." : Period Period •^pod tipL.j 24 July 10 Aug. 6 (b) Do do July 20 : July 22 Aug. 10 Aug. 14 ( '") July 1 do Oct. •'0 (6) .July ''0 "Do (b) July 22... (d) July 31 Aug. 22 do P'eb. 18 180 203 (e) Do ((/) Do Aug. 23 153 177 [b) open air. They were protected from Up to 11 o'clock a. m. they were also a For details regarding oviposition of these ticks see Tables I and II b The seed ticks were in open-bottom test tubes in sand in the o the dlrpft rays of the sun at all times by a cheese-cloth screen " shaded by the house. c In open-bottom test tubes in soil exposed to sun at all times. d In open paper pill boxes outdoors, protected from sun and rain at all times. Considerable numbers of seed ticks in all lots hatching after August 23, 1906, are still ahve (February 20, 1907). LiFE HISTOKY OF CATTLK TICK. 27 PARASITIC PERIOD. The data already given regarding- the periods of preoviposition, incubation, and survival of seed titks have an important bearing on the time required to free pastures or other inclosures from ticks i)ro- vided the cattle are removed. The data given under the present head- ing, on the other hand, show the time required at different seasons to free cattle of ticks by placing them in inclosures from which the ticks have been eliminated either hy systematic starvation or hy the use of naturally tick-free areas, as, for instance, fields that have been in culti- vation for one crop season. In this work we have utilized a grade Durham steer, 17 months old at the beginning of the experiments. (See PI. II, fig. 1.) By means of kerosene emulsion he was carefully cleaned of the thou- sands of ticks infesting him when obtained. Thereafter he was thor- oughly washed to remove traces of the insecticide and hundreds of seed ticks were applied. Under proper precautions to avoid the steer's accidental infestation, these ticks were allowed to reach maturity. ^\iter the ticks of each infestation became adult the steer was thoroughly cleaned and placed in another inclosure, which in each case had been carefully disinfected by means of spra3^s. This process has now been repeated until ten infestations have been reared covering the period between August, 1905, and March, 1907. The details are given in Table VII. In rotation systems the minimum developmental periotl is the most important, because the cattle must be removed l)efore the earliest developed ticks have had offspring to reinfest them. Therefore special reference is made in the table to the shortest periods found, although the longest and the averag(^ are both given. The following deductions may be made from this table : 1. The period from attachment to dropping ranges from 21 to 58 days. It should be noted that in the longest periods the limit was reached by only one or two belated ticks, the majority approaching the average. 2. The average period ranges from 26.5 to 43 days. 3. The average parasitic period is normally souk^ tlays longer in winter than in summer. But warm winter weather, as happened in infestation No. 9, may reduce the period even below the average for the summer. 4. The slowest developing ticks of one infestation may occupy from 10 days (in the summer) to 32 days (in the winter) longer than the most rapidly developing ones. The rapidity of development of the ticks of the same infestation depends somewhat upon their location. Those on the portions of the body where the blood supply is most abundant develop most quickly. In general it seems that heavy infes- tations tlevelop a little more quickly than light ones. This may be 28 NORTH AMERICAN FKYER TICK AND OTHER SPECIE^ due to the fact that, in hght infestations with widely scattered ticks, fertihzation is less likely to take place than in other cases where the males may fuid the females more readily. We have been unable to determine that unfertilized females occupy longer in development than those that are fertilized, but our impression is that they do. The table also shows that the principal variation in the time of development of the ticks of the same infestation takes place not in tho larval or nvmphal but in the a(hdt stage. Tahlk \ll.— I>< rflopiiinU of .\furyaropii.s tnuuilaltis on star at Dallas, Tex. Ap- ph- ca- tion When appliod. No. 1 1905. Aug. If) Sept. 27 Nov. 11 4 (i 8 !) 10 1900. Jan. It) Aug. 2 Sept. 5 Oct. b Nov. 29 n 1907. Jan. 1 Mini- inum Second larval I molt, stage. I Aug. 28 Oct. 4 Nov. 22 Jan. 25 May 31 Days. 12 \ug.lO-ll Sept. 12 Oct. 14 Dec. 8 Sept. 2 Oct. 12 Nov. 28 Feb. :i June I) July 10 Aug. 18 Sept. 22 Oct. 21 Dw. 14 Adults dropped. Mini- Mini- nym- phal 1 First, stage. Last. pe- riod adult stage. Day.^. Days. 5 Sept. 15 Sept. 27a 13 8 Oct. 21 Nov. 8 9 li Pee. S Jan. 9 10 ii Fell. 17 Mar. 8 14 j C. June 14 .lune ;« 8| Inly 24 Aug. 5 8 7-8 Aug. 25 Sept. 11 7 10 1 Sept. 2(i Ot^. U 4 7 Oct. :«) Nov. 12 9 11 Dec. 22 Jan. 1 8 ti Jan. 24 Kel). -.i 10 N^eTi l^"'od from "^ I attaciiment to ,ov- dropping. , 1 drop- Maxi-, Mini- j Aver- ped. mum.:inum. age. Days. 3() .■53 43 41.5 31 31 31.5 2(). 5 :«. 5 28 Days. Days. 20 42 30 10 42 24 13 .'59 27 11 51 :g 9 ;S9 23 37 25 14 40 23 23() 31 21 2(H) .37 24 55 .33 23 35 33 23 DEVELOPMENI" ON HOST. When the larval tick.s (hid t hciiis("lv(>s on the host they rapidly dis- appear in the liair and jittach themselves to the skin. They are principally found on such ])arts as tlie legs, bell}', and dewlap that come in contact with the bunches on the grass, but maybe found on an}' part of the host. In cases of severe infestation they practically cover the entire surface of the body, even the eyelids being infested. In from 7 to 12 days the larval ticks molt and enter the nvmphal stage, in which they have eight instead of six legs. The nymphal stage is further distinguished from the larval stage by the presence of a pair of large stigmata quite in claced. TMs tick was found detached on March 1 and trying to crawl out from the hairs which had been glued together to hold it in place. At tliis time it was not fully engorged. It began depositing eggs on March 18, and con- tinued oviposition until April 26, reaching a total of 523 eggs. An attempt was made to cause these eggs to hatch, but without success. It is not likely, however, that the failure to hatch was due to the experience of the tick. It is probable that the state of engorgement may have had sometliing to do with the matter, and, moreover, at the time of the year when the eggs were under observation it is exceedingly difficult to cause them to hatch. After the experiment that has been mentioned repeated attempts were made to obtain other cases of reattachment. Ticks at various stages were placed on « Lahille (Contr. 1' Etude Ixodides Ai-gentine, p. 112) had previously detailed a num- ber of experiments in the reattachment of Margaropus {Boophilus) microplus. It was found that immediately after molting the ticks would more or less frequently reattach after being removed artificially. Nothing, however, was found to indicate that the parasites naturally detach and reattach on the host. 80 NOETH AMERICAN FEVER TICK AND OTHER SPECIES. the steer and confined to limited area by means of vaccination shields. In no case under this manipulation did reattachment take place. Recently, however, a tick removed just before the second molt became adult in a pill })ox and reattached after 25 hours. ADULT STAGE. Adult females are the ticks that are generally seen, and their appearance is familiar to most persons. The males (which do not become engorged) are generally overlooked, although they may be easily found attached to the skin of the host direct h- beneath the females. This gives rise to a rather prevalent popular idea that females carry young with them. The following descriptions are taken from the work of Salmon and Stiles:" Afale.—liody ..val. naiTowed „n Innit, bn.adost (J. 3 inin.j at s^iigmal plane, 2.15 to 2M mm. long. Scutum reddish ')rown, covering entire dorsal surface, prolonged in front by two pairs of i^rojections— one pair of more prominent dorso-lateral projections, dorsal of anterior projection of coxas I, and one pair somewhat less prominent and more median, ventro-median of first pair and nearer the neck. Two cervical furrows shallow, extending more or less distinctly 1o the posterior border; may be somewhat interrupted in the middle; a median furrow present in posterior half, may be very indistinct; posterior margin of body divided into festoons, which mav be only slightly marked. Relatively large circular pores, witli extruding .short bristly hairs, scattered over entire surface. Eyes small and pale, often problematic, at I intercoxal space Ventral surface lighter tlian dorsal, all portions provided with short stout hairs; geni- tal pore, broad, transverse, between coxte II; anus slightly posterior of stigmal pUine- (wo pan-s of anal plates (clypei): one pair elongate, rectanguhu- lo triangular, close to anus, in some cases extending cephalad to middle of coxa- IV. and caudad to near or beyond posterior margin, tlie anus being about at the middle of the length, in other (;ases extending from height of middle of stigmal area to beyond posterior margin of body; the median border longer than lateral border, the former prolonged into a point posteriorly, the postero-lateral margin may be nearly straight, or somewhat curved, or irregular in outline, thus presenting broad tooth-like projections; lateral and contigu- ous to each of these shields is found another shield somewhat similar in form, but smaller in size. Median caudal appendage ab.sent. Capitulum 450 to 500// long, ' base similar to that of the female, but a little straighter, longer, more salient in front of dorsal shield, into which it penetrates by a sort of rectangular neck, lateral projec- tions not very prominent. Mandil>les mOn long, digit about 90//; internal apophysis with straight base and broad iMfuh' point; external apophysis bidentate, the terminal subventral tooth may be very small while the proximal tooth is strong and large, or both may be large. Hypostome similar to that of female, four distinct rows of tee'th on each half. Palpi about 190// long, similar to those of female. Legs strong; coxae large, those on each side contiguous, as broad as long; coxaj I triangular, apex may be pro- longed anteriorly beyond the corresponding anterior point of dorsal shield, reaching anterior angle of base of capitulum, or may be very short, base posterior and more or less distinctly bidentate, the teeth short, often slightly pronounced, or quite promi- nent, the lateral tooth in .some cases prolonged into a well-marked spine. Tarsi like those of female. " " The cattle ticks (Ixodoidea) of the United States: - 17th Ann. Rept. Bur. Animal Industry, U. S. Dept. Agric, pp. 420-424, 1901. LIFE HISTORY OF CATTLE TICK. - 31 Female. — Body elliptical, as broad in front as in back, usually somewhat con- stricted in middle, near IV pair of legs; may attain 13 mm. long, 7.5 mm. broad. Color exceedingly variable; live specimens vary from a tawny yellow (younger forms) to an olive green (very old specimens), alcohol specimens from yellow to red or black; the excretory system often shows tlu-ough the cuticle as tortuous whitish canals. Dorsal shield (scutum) very small, visible as a dark brownish spot in a depression at anterior end of median line; usually about 1.1 mm. long by 0.8 to 0.9 mm. broad, decidedly emarginate anteriorly to receive capitulum; lateral borders nearly straight and par- allel- in anterior portion, from antero-lateral points to eyes, then convergent from eyes caudad, forming a more or less bluntly rounded posterior angle in median line; cervical grooves 'divide the anterior half of scutum into three more or less equal lon- gitudinal fields, and diverge posteriorly; surface of scutum provided with short bris- tles which are more numerous near anterior border and near the eyes than elsewhere. Eyes rather small near anterior third of margin of scutum. On nearly the entire length of dorsal surface of body are two antero-posterior grooves, interrupted or nearly effaced near plane of IV pair of legs, and ending a short distance from the shield and from posterior margins of body; also, an unpaired median groove in posterior half of body; all three vary with the muscular contractions and may more or less com- pletely disappear when body is replete. Ventral surface shows four pairs of mon; or less distinct marginal constrictions corresponding to the four pairs of legs, the IV constriction being most marked, antero-median region also depressed at insertion of capitulum; vulva small, median, at plane of coxae I; sexual grooves corresponding to the paired dorsal grooves; but showing some variation in different specimens; median groove extending from anus to posterior margin. Anus about on border of second and last thirds of body. Stigmata short oval; stigmal pore slightly crescentic, convexity lateral; stigmal field with numerous larger and smaller wart-like structures, forming a zone near the margin. Cuticle of entire body finely wrinkled, liearing short hairs. Capitulum very short, about 800// from posterior dorsal margin to anterior end of hypostome; base of capitulum hexagonal, enlarged on its dorsal surface: in- serted in emargination of scutum; lateral projections not very prominent. Mandibles 860/^ long, digit 120//. Internal apophysis conical (Neumann), bidentate (Fuller), with its base near the terminal extremity; external apophysis with tlu-ee successive teeth, one terminal, subventral, small; the second stronger; third large. Hypostome rather spatulate, broad, a little longer than the palpi, provided on each half with four rows of nine to ten nearly regular denticles, which do not extend to the base. Palpi very short (310/0, subconical, articles at least as broad as long; first article par- tially hidden under the antero-dorsal border of the base of the capitulum; second article pedunculate, dilated in a salient crest in its middle portion, thus forming a prominence inward (toward median line) and outward, and provided with strong hairs, especially on the inner prominence; third article smaller, subtriangular on its dorsal surface, where it forms a projection in and out; fourth article small, cylindrico- conical, infero-terminal. Legs rather thin, short (pair I, 2 mm.; pair II, 2.5 mm), yel- lowish brown, first articles darker than the others. Coxae: pair I subtriangular, pos- terior border bidentate or biundulate, the division in many cases indistinct. Tarsi I unicalcarate, II to IV bicalcarate. Pulvillum about half as long as claws. Stiff l)ristle-like hairs on all articles. EFFECT OF CONTINUOUS COLD AND HEAT ON ENGORGED FEMALES. Twenty-five ticks were used in the experiments with cold, which were conducted durmg the month of August, 1906. A mean tem- perature of about 48° F. was maintained, with extremes ranging 82 NORTH AMERICAN FEVER TICK AND OTHER SPECIES. from 34 to 53 _. M ith exposure up to 300 hours practically all ticks recovered and m most cases deposited viable eggs. In cas;s of more than 300 hours exposure practically all ticks survived, but none deposit(Hl via})le eggs, although in many instances oviposition took JV ?noo^'' ''^ ^-^P^""^^"t« with heat a mean temperature of from J8 to 102 was mamtamed. Up to 103 hours of exposure to this temperature practically all ticks deposited eggs that were viable With exposure at the same mean temperature of from 144 to 21S hours duration, eggs were deposited, but were found not to be viable 1 hey were dry and shriveled when deposited Some of the females survived heating for the h.ngest period, namely, 218 5 hours \Vith an exposure of 103.5 hours or more, however, a least one-half succumbed. EFFECT OF DIRECT SUNLIGHT ON ADULTS. Eleven unengorgcd fcn.ales placed i„ a box exposed to the direct ^- of the ju,n m SeptemW died in three days. Seven unmatured females m dirc^c sunhght from morning until noon seemed dead at noon. They did not survive until the next dav, although they were removed from the direct sunlight at 2 o'clock." Similar experiments showed that death resulted in the case of engorged females after a few hours exposure to the sun. In experiments with eggs, tubes were sul,jected to direct sunlight for one day. Wlu>n n.oistened while kept^ ui these tubc^, hatching seems to take place normally, and hatching foll,>w(Ml m similar experiments in ^vh\v}x the e-o-s were kept dry. '^'^ EFFECT OF SUBMERGENCE IN WATER ON ENGORGED ADULT TICKS. Adult ticks have remarkable resistance to the elFect of submergence as has been pointed out to be the case with eggs and seed ticks. The iinmediate effect of submergence is to cause a cessation in the activ- ity of the ticks, while they become somewhat distended apparently from the absorption of water. In August and September, 1905 a considerable number of experiments were conducted in which" the adult ticks were submerged in water from the city mains at Dallas I ex. Judging by the experiments with seed ticks and eggs mentioned elsewhere it is not likely that water impregnated with foreign matter would have changed the results. During the months mentioned a period of submergence of 24 hours did not result in the death of any appreciable number of ticks used in repeated experiments After one or two hours the specimens recovered from the immediate effect of submergence and proceeded to deposit eggs which were found to be LIFE HISTORY OF CATTLE TICK. 38 viable. With between 24 and 48 hours' submergence the number of ticks that recovered diminished rapidly. Occasionally specimens recovered after a period of submergence of over 48 hours. For instance, the specimen collected on July 12 and submerged for 50 hours survived and deposited viable eggs. Later in the season (that is, in October) somewhat difl'erent results were obtained in experi- ments in the submergence of adults. In this month many ticks recovered after from 50 to 90 hours of submergence. In fact, fully 50 per cent of the ticks submerged between these extremes regained their fidl activity. In one experiment two out of five ticks sub- merged in October for 91 j hours recovered and deposited viable eggs. Nevertheless a number of ticks submerged for 115| hours did not recover. The results that have been mentioned above indicate that where engorged ticks fall from cattle that are standing in permanent pools of water none will survive to deposit eggs. At the same time the results show that temporary flooding of from 24 to 100 hours' duration would not in all cases prevent ticks from depositing eggs. It must be noted in this connection, however, that the vitality of eggs depos- ited by ticks just prior to temporary flooding would not be interfered with by the water, although, of course, they might be washed away. DROPPING FROM HOST. It is a more or less prevalent popular idea that ticks have some sense which enables them to drop from a host in places favorable for oviposition. A few observations have shown, as was supposed in the beginning would be the case, that there is probably no such power of perception present in the cattle tick. The popular impres- sion probably had its origin in the fact that bunches of seed ticks are found most numerously in the places where the cattle collect for the benefit of shade or water. This phenomenon obviously is due merely to the collecting and standing of the cattle. Many observations seem to show clearly that there is no preference as to the time of dropping. In our experiments many ticks have been known to drop from host during the night and many others to drop during the day. LOCOMOTION. Some attention has been paid to obtaining data on the distance engorged ticks may travel after dropping from the host, since tliis has a practical bearing on double fencing in eradication work. In some experiments specimens w^ere placed on the floor in the laboratory and allowed to move at will. The total movement varied from 24 inches to 123 inches, the latter distance being covered in 52 minutes. 5795— No. 72—07 'd 34 NORTH AMERICAN FEVER TICK AND OTHER SPECIES. The effect of antiheliotropism was always in evidence in these exper- iments. The hght was admitted from different quarters at (hfferent times and the ticks ahvays changed their course so as to travel awa}' from it. These results are very similar to those published by Lahille from experiments with Afargaropus (Booj^hilus) microplus in Argen- tina. The distance engorged females will travel depends upon how soon they can reach shelter. If the}^ obtain protection under debris of any kind the}'^ seem to be disinclined to go farther. The greatest distance traveled on the ground out of doors was only 24 inches. It is popularly supposed that engorged female ticks often burrow into the ground. In a nund^er of experiments with light barnyard trash in tubes it was found that females will work their way down from one-half to IJ inches. In such cases the masses of eggs assume various shapes on account of the surrounding debris. (See PI. I, fig. ].) It was found that seed ticks from eggs so deposited had no difficulty in reacliing tlie surface. HOST RELATIONS OF THE CATTLE TICK. Margaropiis nnnvlatus was descril)e(l in 1S21) by Say "'from speci- mens taken on a Virginia deer in Florida." Since that time we have been unable to find records of the occurrence of the species on deer. However, a nundjer of instances have come to light recently in which undoubted specimens of Margaropus annulatus have been found on deer. The first of the.se cases was the result of an examina- tion made by Mr. R. C. Howell on a herd of tame deer in a park at Mount Pleasant, Tex., in October, 1905. Since that time Mr. J. I). Mitchell has found specimens on a deer at Oakville, Tex. Mr. T. R. Coker lias sent specimens from the same locality and host. In both of these instances the ticks were found on wild deer that had just been shot: In February of the prescmt year Mr. F. C. Pratt collected a few sj)ecimens of Margaropus annulatus from a dry deer liide at Kerrville, Tex., and in December he examined a fresh liide on which considerable numbers were found. The matter of the possible develoj^ment of Margaropus annulatus on various animals, among them guinea pigs, rabbits, dogs, and cats, has been studied by various investigators. Dr. J. W. Connaway's experiments in ^Missoin'i in 1897 showed that the ticks would not attach to rabbits or guinea pigs. They did attach to dogs in consid- erable numbers, but only one of them ever matured. Recently Air. B. II. Ransom has repeated the experiments with rabbits, dogs, and cats. On rabbits and dogs the ticks attached, but remained so only a short time. On a cat a female tick remained attached from July 25 to August 30 and molted on the host. Nevertheless, it did not reach engorgement. HOST RELATIONS OK CATTLE TICK, 85 In our experiments with ticks we have kept several dogs primarily for experiments with species other than Margaroims annulatus. At the same time we have repeatedly sprinkled thousands of seed ticks of Margaroims annulatus on these dogs, but in no case have we noticed that attachment took place. This, with the work of Comiaway, Schroeder, and Ransom, seems to indicate that dogs can play but a very unimportant part as hosts for the cattle tick. Ransom men- tions the fact that the collection of the Bureau of Animal Industry contains specimens of Margaropus annulatus collected from a dog, from which host Francis (1894) seems to have been the first to report it. One of the writers has had one case of an attachment of Margaropus annulatus to his person. This was a male specimen that attached between the fingers of the hand. It was removed after about half an hour. Mr. Ransom mentions a similar case in which, however, the specimen was a female and remained attached to his hand for twenty- four hours before it was removed. Attachment to human beings must be very rare. The junior author had worked with thousands of specimens of ticks before and after the single case of attachment that has been mentioned. In addition to the abnormal and unusual host relations mentioned above, there are not infrequent instances in which Margaropus annu- latus has been found to occur on horses, mules, and asses. All this work shows clearly the remarkable host restriction of the cattle tick that is most important from the viewpoint of its attempted eradication. The early records of Packard, showing the occurrence of the cattle tick on a porcupine and a similar record of its occurrence on the rabbit in Idaho, must have been due to a misidentification of the species. The strict instinct for the proper host in the cattle tick is shown in the extreme infrequency of attachments of ticks to each other. Thousands of ticks have been sent to the laboratory alive inclosed together in tin or wooden boxes. In only one case was it found that a tick had inserted its rostrum in another. This happened in a lot collected in southwest Texas by Mr. J. D. Mitchell on April 19. A female had inserted its beak firmly on the lateral dorsal portion behind the posterior coxse. The two specimens were placed in alcohol and still remained connected." RELATION BETWEEN RATION AND TICK INFESTATION. For several months after experiments were started at Dallas in placing seed ticks on the steer used for experimental purposes it was found that a surprisingly small proportion ever became adult. In "Since the above was written important discoveries regarding the occurrence of Margaropus annulatus on sheep have been made by the Bureau of Entomology. See Circular 91, Bureau of Entomology, U. S. Departmentof Agriculture, issued July 3,1907. 3(3 NORTH AMERICAN FEVER TICK AND OTHER SPECIES. man}^ cases from 5,000 to 10,000 seed ticks were placed on the animal, but only from 1 to 20 adults ever developed. Prof. H. A. Morgan made the suggestion, based upon the observations made by him in Louisiana, that the ration the steer w^as receiving was responsible for this remarkably small proportion developing. At his suggestion we changed the ration. The steer had been receiving daily 4.76 pounds of corn chops and 5 pounds of prairie hay. The inspection tag on the chops guaranteed not less than 9 per cent protein crude and not less than 4 per cent fat crude. At Professor Morgan's suggestion the corn chops were eliminated. Immediately a much larger percentage of seed ticks developed to adults on the animal, although his general condition did not seem to have been changed materially. While before a dozen adults from many thousand seed ticks was the maxi- mum, after the change in the ration hundreds developed fr<^m no larger numbers of seed ticks applied. ENEMIES OF TICKS. At one time it was supposed that sowbugs may sometimes be im})ortant factors in the destruction of tick eggs. A number of observations have shown that the greatly preferred food of these isopods is vegetation either live or decayed. In laboratory experi- ments Armadillidium vulgare was found to feed on dead ticks and also to devour the eggs whenever no other food was provided. Thirty- eight sowbugs, furnished with 897 tick eggs, consumed 366 at the rate of 3 eggs per day each. In another case two sowbugs devoured 159 tick eggs at the rate of 15 each per day. These results hardly seem to substantiate the impression that sowbugs may be of considerable economic importance. It should be emphasized that the experiments referred to were conducted in the laboratory, and the sowbugs were deprived of other food. Under natural conditions the results might have been quite different. The little "fire-ant" (Solenopsis geminata Fab.), which has recently been found to be acquiring a special taste for the boll weevil, undoubt- edly destroys many engorged ticks that have dropped to the ground. Experiments performed by placing ticks in the immediate vicinity of nests of this ant show that under such circumstances they must invariabl}' be killed. The nests of this ant are found throughout the pastures in the South, and the total of the work done by them must be considerable. A number of dipterous larva? have been found feeding upon tick eggs and an undetermined species of Phorida^ has been bred. At one time we were inclined to believe that a chalcidoid parasite of the cattle tick had been reared. Early in 1906 such a parasite was found in a pill box with the remains of an engorged tick placed there the fall before. Upon sending the specimen to Dr. L. O. How- ENEMIES OF TICKS. 37 ard it was learned that it belongs to a new species and creniis. Chalci- doids of the subfamily to which it undoubtedly belongs are known to be parasitic on various dipterous larvse. Upon reexamination of the remains of the tick a portion of a dipterous cocoon was found. Con- sequently the hymenopteron was probably not a parasite of the tick, although the interest remains, since the dipteron was probably para- sitic on the tick. A number of observations have been made showing that domestic fowls frequently learn to remove ticks from cattle in barn lots. Mr. F. C. Pratt observed a case in which the fowls regularly visited hides hanging up to dry for the purpose of picking up the ticks which dropped from them. Mr. J. D. Mitchell has witnessed '" jackdaws " (Qaiscalus major macrourus) picking ticks from cattle near Victoria, Tex., and the farmer informed him that he believed these birds kept the cattle practically free of engorged or nearly engorged specimens. Mr. S. E. McClendon, of the Louisiana Experiment Station, informs us that he has repeatedly seen kingbirds ( Tyrannus tyrannus) engaged in the same work. In connection with the enemies of ticks it may be stated that it seems likely that mice are of some importance. In the laboratory it was found that the best bait for mouse traps that could be used was engorged cattle ticks. It seems likely that in the pastures field mice may frequently devour ticks. Button and Todd (Human Tick fever, p. 17) write as follows: "Ticks are not without natural enemies. Rats eat adults with avidity, and ants carry off young ones and eggs. We have lost ticks in both ways. One occasion over two hundred young ticks were carried off in a single night by small ants." These remarks apply to OrnitJiodoros mouhata in West Africa. THE PRACTICAL APPLICATION OF THE INFORMATION RECORDED IN THIS BULLETIN. In the preceding pages at difl'erent places the special practical importance of the data discussed has been mentioned. As a matter of fact the work upon which this bulletin is .based has been planned to accumulate additional information for use in the practical work of tick eradication. Some methods of control are satisfactory in certain districts, but much less so in others. Plans that would be feasible along the northern border, for instance, where the tick is on a rather delicate equilibrium and is never found on the cattle for months during the winter, would not be applicable to the moist regions along the Gulf where the cattle are infested throughout the year. Of the various methods of eradication undoubtedly those of the widest utility are the ones which prevent the development of the tic4cs by breaking up the relation between them and the cattle. Of these, the more important are the feed-lot or soiling system for relieving the 38 NORTH AMERICAN B^EVER TICK AND OTHER SPECIES. cattle of ticks and the pasture-rotation system (to be used in con- junction with the former) for freeing the pastures. In the feed-lot or soiling system the basis is the time occupied for development on the host in connection with the time from the drop- ping of engorged females to the hatching of seed ticks from eggs deposited by them. In a tick-free inclosure, as a feed lot, cattle may be left to drop their ticks until it is time for the eggs from the first-dropped individuals to hatch. Information as to exactly when it will be necessary to move the cattle to avoid reinfestation is given in Tables I and II, which show the numbers of days at different seasons before ticks begin to oviposit after dropping and the time before the first eggs deposited will hatch. In July, 1906, for instance, this was from 25 to 27 days. The time required for all ticks to drop from cattle, which indicates how long they must remain in one or more, tick-free areas, is shown in Table VII. The period is from 31 to 59 days. The data necessary for an intelligent plan of freeing pastures, by removing the cattle until the death of the ticks, are given in Tables V and VI, showing the period from dropping to the death of all the resulting seed ticks. The former table shows tiiat if cattle were removed from a pasture on June 20, 110 days later it would be per- fectly safe to consider it tick-free. The data referred to above, together ^^^th the results of other experiments, have been arranged to cover maximum preoviposition and maximum oviposition periods, for convenience, in Table VIII. Table VIII.— /'(7-/o(/.s^ in the life hif. Second and third palpal segments extend laterally into sharp points; stigmata nearly circular Genus Mnrgnrnpvs (p. 40'). Second and third palpal .segments even: stigmata comma-shaped. Genus Rhipiccp/irilus (p. -17). 4. Eyes present; external hordor of ])alpi straight; cox:e I Indcntatc. Genus Ddiuaccnior (]>. 49). Eyes absent; external l)or(U'r oi palpi uneven; coxje I not l)idciilalc. Genus //.riiKiphi/sdlis (p. 52 K Subfamily Ixodin k. o. Anal groove surrounds anus anteriorly and opens jjostcriorly; eyes absent; stigmal l)late nearly circular Genus Ixodes (p. 54). .\nal groove surrounds anus posteriorly and opens anteriorly; eyes present; stigmal plate reniform Genus Awblynmma (p. 58 ). Lahille has recentl}'" published an inoenioiis gra])hic tal)le for the separation of the famihes and genera of Ixo(k)idea. Tt is reprodticod Familias Argasidae (^ SUB-ORDEN: ArPAGOSTOMA "c^'^.'^^ - Argas (X nrnithodoro5 - <^ HagmaphusaliS" ^ -JW Aponomma " ^ J*% _ Neumanmeiia lxodid«( ^ I ^,^ Ambluomma Art^opliL^^ . ., O Anopli po-^^^^^i Ommataj C^M^ [)pf mdcenlof ' |j)^...„_^- HLjalomma mh Rhipicephalus " '^^- 1 ^' \^ t^ @----Boophilus" Penssoplij O I ^ -•■■ ■ "r^" . , .g^% Anoi^ata W. L schalocephalus Fig. 2. liraphictable for the separation of tlic familu>s and genera of ticks. (From Lahille.) The underscored genera ato represented in the United .States. here as figure 2. The genera underscored are known to be repre- sented in the United States. The suborder Arpagostonia of Lahille is the same as the superfamily Ixodoidea of Banks, used by us. Family ABGASID-ffi. The family Argasida^ is represented by two genera, Argas and Ornithodoros. They are readily distinguished by the characters given in the table. The species are parasitic on mammals and birds. olxodides Argent., 1905, p. 21. 42 NORTH AMERICAN FEVER TICK AND OTHER SPECIES. Genus ARGAS. The species belonging to the genus Argas are nocturnal parasites of chickens, pigeons, and other birds, and occasionally attack mam- mals, man included. Two species are represented in this countr}^ — ^4. miniatus Koch and A. sanchezi Duges. The former has been found by Marchaux and Salimbeni to transmit spirillosis of fowls in -Brazil. There is some evidence of the occurrence of this disease in the United States. ADOBE TICK. i Ar common name used above. KOWl. TICK. {Art/da iiiiuidliis Kocli.)" This species was described in 1S44 by Koch from Demerara. The name Argas americanus, applied by Packard in 1873 and used largely by writers in this country, is a sj^nonym of A. miniatus. For excel- lent illustrations of this species see Salmon and Stiles, Ixodoidea of the United States, Plate LXXII and text figures. The species is well distributed over the world. The records include Persia, ^Vlgeria, Russia, India, Australia, South Africa, Central and South America, and, in the United vStates, Florida, Texas, New Mexico, Arizona, and California. In southwestern Texas it is found in large nund)ers in and alxmt chicken houses and out-door roosts, hiding away in crevices by day and coming out at night to engorge on the fowls. This species seems occasionally to attack mammals, as Mr. J. D. Mitchell has taken it once in Texas from the rabbit. As pointed out b}" Lounsbury, the sexes are so much alike that, except by the size, the onl}^ safe way of separating them is through the form of the genital orifice. To quote from him, "This orifice [genital] is situated just behind the mouth parts on the under side of the front of the body; that of the male is relatively inconspicuous a The name of this tick is in great confusion. The one used by the writers is that recently adopted by Banks. CLASSIFICATIOlSr AND HABIT8 OF TICKS. 43 and is surrounded by an oval ring, and that of the female appears as a transverse slit in the leathery surface. Both sexes are of the same dimensions when they become adult. The male, however, does not perceptibly increase in length and width by feeding, whilst the female does, and hence amongst specimens collected about a fowl house the females are generally larger than the males." Its life history has been worked out by Lounsbury at Cape Town. As brought out by him, the life cycle and habits are strikingly dis- similar in some important respects from those of the true ticks, the general habits being found much more like those of the bedbug (Cimex lectularius L.) As might be expected, we have found the stages in the life cycle to vary somewhat from those he found. Unlike the ticks of the family Ixodidse, this species feeds for but a few hours at a time, and then always at night, excepting in the larval stage, when we have found it to remain attached for five to eight days before dropping. There is also an extra nymphal molt. Unlike the ixodid ticks again, these do not die following engorgement, but live on, ovipositing repeatedly. Within a week or ten days from one feeding in warm weather they again find a fowl and engorge. As many as five different feedings as adults have been recorded by Louns- bury, each followed by the deposition of eggs. In our experiments seed ticks were placed upon a fowl and obser- vations made to determine the period of larval attachment. In about three days from attachment they became rounded and black from the engorgement of blood. A few hours before dropping they commenced to flatten and assume the typical Argas shape. Attach- ment continues for from five to eight days. In September and Octo- ber fourteen days were found to pass after dropping before molting took place. The attachment for second and third engorgements Lounsbury found to last but a few hours, about two weeks to pass after the second, and a like period following the third engorgement before moltino-. Table IX. — Ovipnsitinn of Argas nriniatiis at Dallas, Tex. ■ First engorgement recorded.- First oyiposit ion. When collected. From— To— Num- ber of days. ber of eggs. 1906. May 12 June 23 July 4 May 17 | May 30 May 16 May 23 May 17 May 29 May 18 June 3 May 18 May 24 May 16 May 22 May 2 May 20 Aug. 1 Aug. 10 12 14 8 13 .19 10 113 974 Do do Do... do 1.58 169 Do .do Do do 194 Do do 50 Do Mar. 24 Apr. 17-18 Do tin 83 ■ "" 44 NORTH AMERICAN FEVER TICK AND OTHER SPECIES. Table IX. — Oviposition of Argas miniatus at Dallas, Tex. — Continued. Second engorge- ment. Second oviposition. Tliird engorge- ment. Total \Vhcncollcot<'(l. From— iNum- berof To— berof ^ggs- days. num- ber of eggs. 190(;. Mav 12 Do Do Do Aug. 8- 9 Aug. 9-10 .\ug. 10-11 Aug. 15-16 Aug. 17-18 Aug. 23-24i) Aug. 7- 8 Aug. 18-19 Aug. 'U Aug. 15 Aug. 16 Aug. 21 Aug. 24 , 11 180 Aug. 21 7 199 Aug. 25 10 193 Sept. 4 15 1 148 Oct. 22-23 Sept. 3a 454 357 Do Do Oct. 17-18 342 50 Do 32 Mar. 24 Do Aug. i7 Aug. 24 Aug. 24 8 ! 55 Sept. 2 10 ' 154 Sept. 28^29 Oct. 16-17 185 237 a Dead. b Last engorgement. Adult ticks wei^ihed before and after engorgement were found to increase in weight more than 300 per cent. In order to determine the incubation period, 35 daily lots of eggs, deposited between May 16 and September 1, were recorded. Of these, four lots commenced hatching in 14 days, 26 in 15 days, and 5 in 16 days. In the incubator eggs deposited August 21 and subjected to a mean temperature of 99.8° hatched on August 29, the maximum temperature being 108°. From experiments carried out by placing eggs and seed ticks in an ice "box and exposing them continuously, these were found to be exceedingly resistant to cold. Eggs deposited August 27 were exposed from September 8 to October 1 to a mean temperature of 48.9°, a maximum of 67° and a minimum of 37°. These commenced hatching October 6. Two lots of larvae, one of 13, that hatched September 2, and a second of 30, that hatched Septem- ber 8, were exposed in the ice l)ox from September 8 to October 22 to a mean temperature of 45.9°, the maximum being 67° and the minimum 36°. These were all alive when removed and were as active as ever October 25. At Dallas larva? kei)t submerged in water to a depth of about an inch lived for 1 1 da^s. The length of life of this tick and its capacity to exist in the absence of a host are surprising. At Dallas larva? ke])t confined in summer in pill boxes immediately after hatching lived about two months, some surviving somewhat longer. Larva? of Margaropus annulatus kept under similar conditions live for but two or three days at the most. In Australia Robertson found the nymphs to live in pill ])Oxes for about the same j^eriod as we have found the larvae to survive. The longevity of the adult, however, is most remarkable. Riley reports an adult specimen as remaining alive in a corked vial without food for five years." Robertson has found them to remain alive for two years and three months and Dr. Cooper Curtice informs us that he has kept them alive without food for more than two years. In our experiments adults collected in March, 1906, and kept in corked a Pr, Ent. Sue. Wash.. III. p. 121. CLASSIFICATION AND HABITS OF TICKS. 45 vials are still alive, March 1 , 1907, althoii.— Stix- mal plate of i;iiii>i<-(jili(ihis sp., male. FiR. 6.— Sti.Kiiuil plate of Aiuhhitmnini inaruhifiiiii. female. Figa. 1, 2, mncli eiilarwd: tig. 4, more enlarged: tigs. ;i .5, (i, highly magiiitled. (Original.) 72, Bureau of Entomology, U, S, Dept of Agriculturi 2 , ■m^' ^ fe^ Stigmal Plates of Ticks. Fis. 1. -Stigmal philfsand anus ui Ih ninir, „i,„- „it, „.<. iumIc. Fifj. 'J.— Stigrmal plate .if same Fig. 3.— Stigmal plate ol Anihh/onnua raj, ,nirn.« , rualr. Pig. -1.— Same, female. Fig. •^.— .sii.a mal plate of Dermncentur mridhili.--. female. Fig. 6.— Stigmal plate of Bermaceittor occhlciitdlh Highly magnified. (Original.) CLASSIFICATION AND HABITS OB^ TICKS. 49 The incubation period of eggs deposited during the middle of April was 6 weeks and of those deposited at the end of that month, 33 days; seed ticks that emerged the first of June lived for 10 weeks, when kept in test tubes on sand. Attempts were made to rear this species by placing seed ticks on dogs, but with poor success, as few seemed to attach. A dog was infested with seed ticks on May 29, but none could be found attached. On July 13, however, three adult ticks, two partially and one nearly fidly engorged, were found between the toes on a front foot. One of the small ticks dropped July 14 and the engorged one on July 15. In the middle of October several males of this species appeared upon the dog, and these must have come from the above lot of seed ticks. They were found to change the location of their attachment from day to day. Our conclusion is that this species drops to the ground for both molts. Genus MARGAROPUS. Neumann stands alone in suppressing Margaropus (Boophilus) under Rliipicephalus. Although the two groups are closely related, it seems evident, not only from their structure but from their habits, that they form two distinct genera. Neumann's latest arrangement of the forms is as follows: R. {M.) annulatus (Say). Southern United States. E. {M.) annulatus var. australis (Fuller). Australia, the Antilles, and South America. R. (M.) annulatus var. calcarata (Birula). North Africa. R. (M.) annulatus var. decoloratus (Koch). South Africa. R. (M.) annulatus var. caudata Neumann. Japan. R. (M.) annulatus Y&T. .argentina Neumann. Province of Buenos Ay res. Neumann considers that R. (M.) microplus (Canest.) is very prob- ably identical with R. (M.) annulatus var. australis. The first portion of this bulletin deals with the sole North American representative of this genus, M. annulatus (see PL III, figs. 1, 3). Genus DERMACENTOR. This genus is characterized by the presence of cleft front coxae in both sexes, the fourth pair of an immense size in the male but normal in the female. The structure of the stigmal plate furnishes valuable characters in specific determination in this genus as do the porose areas. Salmon and Stiles in 1901 had but three species before them from the United States, which they identified as D. electus Koch (varia- lilis Say), D. reticulatus Neumann, and D. variegatus Neumann. 5795— No. 72—07 4 50 NORTH AMERICAN FEVER TICK AND OTHER SPECIES. The species which they then hsted as D. retindatus Neumann is now considered by Doctor Stiles and Mr. Banks as Neumann's D. occi- dentalis, described from specimens collected in Sonoma County, Cal- ifornia, and labeled D. occidentalis by Marx. The D. reticulafus of Salmon and Stiles is now considered by Banks as alhipictus Packard. While D. reticulatus Fabricius is widely distributed, being found in Europe and Asia, so far as known it has not been taken in this coun- try. D. parumapertus, described hj Neumann in 1901 from 4 female specimens taken at Lakeside, Cal., labeled as taken on a man and in a chicken house; and D. hifurcatus Neumann, from a wild cat in Texas, described as Ixodes and later referred to the genus Derma- centor, seem to come close together, although they may be distinct species. According to Mr. Banks, Ixodes nigrolineatus Packard is a Dermacentor. To those referred to can now be added Dermacentor nitens Neumann, which has been collected by Mr. J. D. Mitchell, of this Bureau, making a total of 7 described species so far known to occur in the United States. AMERICAN DOG <)!{ WOOD TICK. [ Dfrnidrenior raridbilis Say.) Synonymy (on the authority of Mr. Nathan Bankss): D. mnerivanus authors (not L.); D. clcctus Koch, 1844; Ixodes albipictus Pack. (1st Peabody Acad. Rept., p. (iti, not Guide and Am. Nat.); /. quinqnestriatus Fitch, 1871; /. robcrtsoni Fitch, 1871 ; /. pitnrtiiJiiliis Say. 1S^21C.'), This s})ecics is distinguished by the fmely j)unctate stigmal plate (see PI. IV, fig. 5) . It is widely distributed over the country, and has been taken commonly in northern and southern Texas and in Florida on the dog. In some sections of Texas Arnhli/oriinia maculatum and RMpicephahis sp. are the common ticks on the dog, which is also the case with /. scapularis in Florida. Neumann records a male taken on a rabbit, Lepus callotis, by Duges, at Guanajuato, Mexico. Cattle also serve as hosts. Prof. H. A. Morgan records 7,378 eggs as deposited by a single tick between May S and 2(1. These eggs commenced hatching on August 20, an incubation ]>eriod of 27 days. Our records include data on the deposition of eggs by a tick collected April 30, oviposition commenc- ing Mav S. The details follow: T A B 1. K NIL. Or ipos it ion of Dennac ■nlor variabilis H XimilxT of pggs depos ited - c, : 2 ;: :■ i = :: i 1. ' 5 ' 2 ' g ?S , Si s ! ?; , s S S s ii 1 5" i, ' i, 1 & s 1 ^ & 32 72 124 232 251 320 237 246 217 257 ^235 253 ,153 II! 1 1 1 1 ! 1 35 104 34 1 6 , (a) 2802 CLASSIFICATION AND HABITS OF TICKS. 51 In five lots of eggs deposited in April the incubation j^eriod varied from 37 to 43 days. Four lots deposited during May prior to the 10th hatched in 33 or 34 days. Seed ticks that hatched from eggs dejiosited May 10 lived until November S or 10, being alive November 6, but all were dead on November 10. The i)eriod of survival was thus six months from deposition. Under summer temperature Prof. II. A. Morgan found engorgement of the adult to take place in from 5 to 8 days. He concludes that the larva^. and nymphs attach to mammals other than cattle, as the s])ecies has only been found on cattle in the adult stage, and attempts to cause seed ticks to attach failed. np:t tick. {Dermacnitnr orcidcntalis Neiuiiaim.) This species (see PI. IV, fig. G) was received by Marx from Occi- dental, Cal. He determined it as a new species, labeling it D. occi- dentalis. Several writers have made use of this name, but it remained for Neumann to describe it for the first tune in 1904, placing it as a variety of D. reticulatus Fab. Curtice in 1892 referred to it briefly as D. americanum (variabilis). It is now considered by Banks to be a distinct species and is the one referred to by Salmon and Stiles as reticulatus. The true D. reticulatus Fab. is not represented in our col- lections, although it may possibly be found to occur here when a thorough tick survey is made. The species seems to be a western one, being found in the region of the Rocky Mountains especially. The Bureau of Entomology and Marx collections contain specimens from California, Washington, British Columbia, Colorado, New Mexico, and Texas. Salmon and vStiles also record specimens from Oklahoma and Tennessee. In a specimen taken from a deer skin at Kerrville, Tex., we have what is apparently this species, there being some doubt because of the poor condition of the individual. The recorded hosts include cattle, horse, sheep, deer, and man. EI.K TICK. ( Dermaccntor albijyictns Packard.) Dei-maccntor albipictus Packard, Am. Nat., II, p. 559; Guide to the Study of In- sects, 9th ed., -p. 662. Not 1st Kept. Peabody Acad., p. 66. (See Banks, A Cata- logue of the Acarina or Mites, latter in tliis country. He recognizes //. cJiordeilis Packard as tlu^ form occurring in the eastern United States. A South Afi-ican species, //. JeacM, has been determined by Louns- bury to transmit mahgnant jaundice of dogs. The larva and nymph both drop fi-om the host to molt. Both engorge quickly, sometinu^s in less than 48 hours from the time they attach; usually, however, remaining from 65 to 75 hours. HABHIT TICK. {IhevHiphiisdlix 1( pon's-jxilii.^li Synonym: Gonixodes rostralis Diu'es. Packard). Packard described this species (see figs. 7, 8, and PI. Ill, fig. 2) in 1869 from a female sj)ecimen collected at Fort Macon, N. (\, on a Fig. S.—Hscmap,\ y.-alis leporis-palustris: Coxa' of male and female. Greatly enlarged (original). i-abbit, Lepus palustris. Marx reported the species as quite com- mon in Kansas, Texas, and Cali- fornia. Dr. Cooper Curtice has taken an engorged female from a horse in Texas, and it has been col- lected in Mexico, the host not being given. Neumann mentions an engorged female in the museum of Paris labeled ''from Brazil" and a Fig. 1 —Uxmaphy sails leporis-paluslris: ulum and scutum of female, dorsal Greatly enlarged f original). 54 NORTH AMERICAN FEVER TICK AND OTHER SPECIES. molting n}' mph taken on a Paradoxurus by P'orbes in the Malaysian archipelago. Lahille reports it from Argentine Republic. During the past two years it has been collected in Texas by agents of the Bureau at eight different times from rabbits and hares. The species seems to be generally restricted to the genus Lepus, but two instances of other hosts having been recorded and these probably accidental. On the rabbit the ear seems a favorite place for attachment. As a more extensive collection of the tick is made it will undoubtedly be found to occur in a much greater territory than is now known. A few notes on the life history of this species have been made by us. ' \\KI.J ; XIII. — V i posit ion of Unnidj Jnjml ,s Up >ris-p(ilustris. Number of eggs deposited— Total. lo- May 1 May iviay May 24. May 25. May 26. May May May 29. May 30. May 31. June 1. June 2-3. 2G0 no 47 228 70 146 39 48 •1 43 98 7 29 17 72 3 22 22 63! 4 : 14 12 21 13 ^l\ 4 (a) 1,112 57 326 99 7 9 13 7 1 (a) Table XIV. — Period of incubation and longevity of fl:rmaph>isalis leporis-palusliis. Eggs depos- Hatching ited. commenced. Minimum inc'ui)a- tion period. Remarks. May 20-23 May 24-29 September 2-5 . June 20 June 23 September 26 . 3') 24 March 5, dead. March 5, dead. May 11, dead. Subfamily IXODIN^. Three genera of this subfamily, CVratixod(»s, Ixodes, and Ambly- oinina, are represented in the fauna of the United States. They may be readily distinguished. The Ixodes have long club-shaped palpi, the form of the tliird segment being typical of the genus (see PL III, fig. 4). The male and female have only the first coxjb provided with a spine of varying size; the anal groove surrounds the anus anteriorly, opening posteriorly; eyes are present. In Amblyomma the palpi are long but cylindrical; the male has a long spine on the first and fourth coxie, while in the female only the first coxa^ have spines, the others possessing tubercles; the anal groove surrounds the anus posteriorly and opens anteriorly. Ceratixodes, with pointed palpi, occurs on sea birds. Genus IXODES. (The Castor Bean Ticks.) Previous to 1796 all ticks were placed under the Linntean genus Acarus. In that year Latreille erected the genus Ixodes, giving /. ricinus as the type species. For many years following all ticks CLASSIFICATION AND HABITS OF TICKS. 55 were described as belonging to this genus, as is the case with the species of Say, Fitch, and Packard. Of the genera represented in the United States this has the hirgest number of species. Fourteen are recognized, as follows:" /. ricinus L., I. frontalis Panzer, I. scapularis Say, I. fuscus Say, I. brunneus Koch, /. urise White, /. cookei Packard (wSynonynis: 7. cruciarius Fitch, and /. hexagonus of S. & S., on the authority of Nathan Banks), /. arcticus Osb., I. diversifossus Neuni., I. dcntatus Neum., /. angustus Neum., I. 'mchoatus Neuni., I. sndptus Neuni., and I. californicus Banks. Of these, four have been taken in Texas by agents of this Bureau — ricinus, cool'ei, scapularis, and sculptus. Comparatively little is known of the life cycle of the species of Ixodes. The work of E. G. Wheler on ''Louping III and the Grass Tick" (/. ricinus) is about all that has been done. It seems prob- able that all species drop to molt. As Mally ascertained to be the case with /. pilosus in South Africa, we have found engorged females of I. scapularis to dry up in captivity before ovipositing. From Wheler's studies and our experience moisture seems to be a necessity in order that molting may take place. The longevity of the larvae of ticks of this genus must be excep- tional, even when some of the long-lived s])ecies of other genera are considered. Wheler mentions larva? (7. plumbeus?) which hatched on October 9, 1898, from eggs laid in August, that lived until the beginning of August, 1899, or about 10 months. They were kept in a bottle with a sprig of moss and some damp sand. AMERICAN CASTOR BEAN TICK. (Lrodcs cookri Packard.) Synonymy (on the authority of Natlian Banks) : Ixodes cruciarius Fitch ; /. licragnnus S. & S. (not hexagonus Leach, 1815); I. hexagonus var. longispinosa Neuni. This species(P]. Ill, fig. 4) was described by Packard from speci- mens on a woodchuck, Arctomys monax, at Salem, Mass. Neu- mann, in 1899, placed the American form with the European 7. hexagonus, but in 1901 he separated the two as varieties. Salmon and Stiles, in 1901, followed Neumann, who at that time had all their specimens. Banks has examined the National Museum material and considers longispinosa the same as 7. cookei of Packard, but states that there may be a true hexagonus in this country, though he has not seen it. a According to Nathan Banks, /. nigrolineatus Packard is a Dermacentor. 56 NOKTH AMERICAN B'EVER TICK AND OTHER SPECIEi^. We have taken this species in Texas from a goat, a raccoon, and a skunk. Neumann records it as taken in the United States from the otter, mink (Putorius vison), sheep (Texas), spermophile, domestic cat (Maine), fox (Cohirado), weasel, porcupine, and marmot. EUROPEAX CASTOR BEAX TICK. il.rodis rifiuiis LinnaMis. ) From its general distnl)Utioii throughout Euroj)e this species has been called the European castor bean tick. Mr. Banks informs us that in this species the front tarsi are longer than in am^ other species of the genus found in the United States; that in structure it is very similar to /. scajmlaris, but the porose areas are larger and closer together and the scutum is more angulate on the sides than in that species. Neumann, in his list of hosts of the adult stage, includes sheep, goat, cattle, horse, stag, roebuck, dog, cat, fox, ferret, hedgehog, and man; the nymphs and larv.ne having occasionally been found on lizards, birds, hares, rab- bits, squirrels, ])olecats, ferrets, hedgehogs, mules, bats, and mice. In the United States he lists it from Maryland, ''Carolina," Florida, California, Kansas, and Texas, on Lepus sylvaticus, Fells pardalls, cattle, opossum, gray fox, panther, and wild cat. While we have expected to find it frecjuently in Texas, in but a single instance has it been taken. This was by Mr. F. C. Pratt, at Mountain Home, from a dog. In Louisiana Prof. II. A. Morgan reports it as found on mink in all its stages, but on cattle only in the adult stage. Although this is an old and widely distributed species, but little study has been made of its life history, that of E. G. Wheler, of Englantl. in 1S09, standing practically alone. His most valuable studies were made to di^termine the relation of the tick to "louping ill" of sheep, with whicli.in the light of present knowledge, it seems to have only an accidental connection." The following is the sub- stance of Wheler's observations ma(h» in England and published in 1899: The a(kut fenuiles are readily recognized before they become dis- tended by their deep-red bodies, dark-brown legs, sliield, and other points. The males are of a uniform dark brown. A record of 2,050 eggs fi-om a single female is given, and a very interesting account of the remarkable process of oviposition. I^arvae, upon fmding a host, attach, and remain for aliout 2 days, by wliich time the}^ are distended, black, and globular. Fully distended larva? received February 7 and kept in a bottle became hard, dry, and torpid, but on April 29, after 11 weeks, were found to have changed into nymphs and resumed active habits. After molting the nymph takes up its position on the herb- age, just as the larvae had done, for a chance of attachment to a host. o Journal of the Royal Agricultural Society of England, Vol. X, pt. 4. CLASSIFICATION AND HAHITS OK TICKS. 57 Whereas adults seem to, confine themselves niostly to sheep, cattle, and deer, the larvae and nymphs attach themselves very readily to various hosts, such as horses, dogs, and human beings. About a dozen distended nymphs taken from sheej") May 29, though kept moist, had the same dry appearance as the larvae, as before described. These molted about July 19, about 11 weeks after removal from the host. For some time previous they had appeared dead, no motion of the extended legs being perceptil:)le. Of these about half proved to be males. About 10 days passed before the sexes attained their proper color and strength. On reacliing the adult stage both males and females again wait on herbage for a passing host. At tliis time, as well as after distention of the female on the host, an action which appears to be sexual intercourse freely takes place even in confine- ment. The rostrum and other mouth parts of the male are inserted in the genital opening of the female, which is situated between the bases of the posterior pair of legs. On the host the females grad- ually distend, and in the course of so doing vary much in color and appearance, so much so in this case that it is difficult to believe that they are of the same species. Of the exact periods of engorgement we are not informed. Under unfavorable conditions larvae have been kept alive for 4 months. NAmiphs were kept alive for 6 months and adult males and females for 4 months, being still alive at the time of writing (1899). Without moisture, when kept in a dry empty bottle, neither larvae, nymphs, nor adults survived more than 2 or 'S chiys. Females exposed to 25° F. for a night were found to be but little affected. This species, according to recent investigations of Kossel and others in Germany, transmits European piroplasmosis of cattle. The fact that the organism Piroplasma higeminum is the same as is found in tliis country lends great interest to investigations to determine whether /. ricinus may not transmit Texas fever in the ITnited States. BLACK-LEGGED TICK. {I.rodcs srapularis Say.) Say states that tins species is rather common in forests, and is fre- quently found attached to dift'erent animals. Xeumann has not recognized the species, but Banks has identified it with a form com- mon in some parts of the South. In Texas we have collected it from deer and dogs, and in Florida from dogs. In the latter State it seems to be very common, and was taken at Havvthorn, Orlando, and Fort Myers. This species is remarkable for the size that the engorged seed tick reaches. These are as large or larger than the engorged nymph of Margaropus annulatus, although the adult is not as large as the adult Margaropus. Large numbers of seed ticks and adults have been 58 NORTH AMERICAN FEVER TICK AND OTHER SPECIES. taken on dogs, though as yet not a single nymph. Tliis suggests the remote possibiht}^ that the species may pass from the larval to the adult stage at a single molt. SrrLPTl RED TICK. {Ixodes sculptus Xtniinann.) This sj^ecies was descril)ed in 1904 from a female specimen taken with a female /. ricinus in the Santa Cruz Mountains of California. So far as known it had not been taken since until Mr. F. C. Pratt col- lected it on prairie dogs at Sherwood, Tex., November 2, 1906. More extensive collection will undoubtedly show a wider distribution than is now known. Genus AMBLYOMMA. The species of the genus Amblyomma are distinguished by the palpi, which are long and cylindrical. The male has the fn-st and fourth coxa^ armed with a long spine; the female has only the first cox;e with a spine, the others with tubercles. As far as known all the species drop from the host for each molt. Lounsbury has found Amhlyomnia lichrnum to be the transmitter of heartwater in cattle, sheep, and goats, and has carefully worked out its life history. The genus is represented in the Ignited States by four species — americanum, cajerniensc, maculaturu, and tuberculatum. A fifth species, A. multipunctum, is described by Neumann from two speci- mens taken on a tapir and an antelope (Dicrmiocerus furcatus) in ''North America." These are reported as collected by Donckier. As no species of tapir is found north of Nicaragua it seems probable that ^'1. ninltipundunt nmst have been takry spot (m the scutum of the female. It is widely distributed, having- been reported from Labrador to Florida, and also from Guatemala and Brazil. After Margaropus annulatus, it is the most important tick in the United States. Though found more commonly on cattle we have taken it from man, horse, mule, dog, goat, hog, deer, scjuirrel, and wolf, and it appears to attack mammals generally. In portions of Louisiana and Texas it becomes a pest of considerable importance to moss gatherers and other persons who spend much time in the forests. It has been repeatedly taken in Texas during the summer of 1906 on the clothes or attached to the body of agents of the Bureau. Packard mentions a case in which one buried itself in the arm of a young girl, producing a raised tumor. In May it was found on a herd of dairy cows near Dallas in large numbers, though only an occasional specimen of Margaropus annu- latus was present. The proprietor of the dairy stated that they were very annoying through their attaching to milkers. Mr. J. D. Mitchell has found it in the vicinity of Kcrrville and Llano, T(>x., to be the most important species, being much more numerous than the fever tick. In that region the cattle suffer greatly from it. Its abundance seems to be due to the large numbers of sheep and goats kept in that section. These serve as hosts, spreading it broadcast, at the same time reducing the bunches of Margarojms annulatus seed ticks. Table XV. — Ovrposilion of Amblyom m,a americanum. Collected- Oviposition. Period of ovipo- sition. Dropping to end of ovi- position. Number of eggs From— To- Mar. 26 May 13 May 25 May 27 do Apr. 20 May 18 May 21 June 5 June 7 June (i June 9 June 5 June 10 Daps. 16 14 9 12 11 14 10 15 Days.^ 22 20 20 19 •22 IS 23 10 Apr. 27 May 2 May 15 2 .108 May 19 5,040 Do 2, 659 Do do.. . 1,736 Do do 950 Do Do ....do... ....do.. . 1,510 1,306 Total... s 21.2 19 137 2. 126 Our records regarding oviposition, as shown in the above table, are from 10 engorged ticks. It will be seen that the maximum number of eggs deposited by an individual was 5,040, deposition continuing for 12 days; the minimum, 950, with a deposition period of 10 days; an average of 2,126 eggs deposited in 12 days. Morgan records as many as 6,519 eggs. 60 NORTH AMERICAN FEVER TICK AND OTHER SPECIES. Table XVI. — Incubation and longevity of Ainblyoinma ainericanuni. Com- menced to hatch. Minimum incuba- tion period. Seed ticks aU dead. Period of— Eggs depo-sited. Oviposi- tion to death. Hatching to deal li. Apr. 1.5-17 June 3 Days. 50 42 42 35 33 Sept. 13 Days. 152 Days. 103 Apr. 2.5 June 5 Miiv 2,S /iiid 29 Mav30;ind 31 July 1 July 1 Nov. ea Nov. 22 103 177 129+ 145 n One or more alive. From the above table it will be seen that the incubation period in April and May is about 7 weeks. Eggs deposited in the latter part of May hatched in 5 weeks. Prof. II. A. Morgan has found some specimens to pass the first molt on the host, drop- ping in about 10 days fol- lowing that molt, or just previous to the second molt. The greater num- ber (h-opped in from 4 to 7 (hiys. The molting of the nymph was found to last 6 weeks. Engorge- ment of the adult in March and April occupied from 7 to 11 days. The resistance of the fe- male to water seems to be similar to that of the fever tick. Seven females were submerged for 18 hours, all becoming active fol- lowing removal from the water. The next day all hours. Onlv one, an unenfrorged Fig. 9.-.4mW were again submerged for specimen, survived. In the adult stage both sexes will reattach, as seems pr()ba])le in the larval and nymphal stages. Mr. Mitchell has observed adults on grass in tlie act of copulation. CAYENNE TICK. ( Anihhjomnta cnjrnnni.^e Fab. ) Synonyms: /. crenatum Say (Banks). A. mirtum Kocli (Banks). I. lie r rem: Duge.s (Neuni.), .1. sculplus Berlcsc (Noum.i. Tliis species was described from Cayenne in 1794, no host being CLASSIFICATION AND HAl^ITS OF TICKS. fil given. The writers' opinion of the specific identity of specimens from Venezuela, on cattle, with Texas specimens, on horse and peccary, is confirmed by Mr. Banks. The species may be distinguished from maculatum readily by the characters given in the table. (See also figs. 9 and 10 and PL IV, figs. 3, 4.) The species has been reported from, and seems to be generally dis- tributed through Mexico and Central America. It has been reported from Colombia, -Venezuela, Brazil, and Argentine Republic in South America. Neumann also reports it from Cuba and Jamaica. In Texas Mr. J. D. Mitchell has taken it in Live Oak County from the peccary and horse. Mr. Banks reports specimens from I^ouisiana, Mssouri, and Florida. In addition to the hosts mentioned it has been reported from toad (Bufo agua), capy- bara (Ilydrochxrus capyhara), an ant-eater, and man. Stoll, in the Biologia Cen- trali - Americana, states that this species is the most com- mon of all Ixodidae in Central America, and gives some in- formation concerning its hab- its. He has never found the male in a parasitic state, but has found it free on grass antl bushes in Guatemala. The fe- male, which he states abounds in the woods and fields on grass and bushes, is occasion- ally brushed ofi" by horses, cat- tle, or dogs, and even man. It adheres tenaciously to the sldn, remaining when undisturbed for several days until filled with blood. If forcibly removed, the beak breaks ofi^ and remains in the wound, causing a disagreeable and sometimes painful inflammation. The young, wliich are distinguished by the inhabitants of Guatemala by the name of "mostacilla," hang to the grass in clusters of thousands, especially during the dry seasons. By their creeping on the skin and frequent biting the^^ form one of the greatest plagues of travelers. In a letter accompanying specimens of tliis species from Venezuela the writers are informed that the ticks do great damage by producing fever in cattle, which become weak and in many cases die. It hardly seems possible that the malady can be Texas fever; nevertheless tliis species may possibly transmit some disease. Fig. 10. — Amblyomma cajennenxe: Coxte of female. Greatly enlarged (original) 62 NORTH AMERICAN FEVER TICK AND OTHER SPECIES. Tablk XVII. — Record nf deposition of an engorged tick, Amblyomma cajennense, col- lected on peccary April 29. Number of eggs deposited— 67 o 1 85 1 278 2 1 S 1^ 22 213 336 307 2 S 1 1 206' 119 >> 60 1 68 1 33 1 1 ll' 3 II 0(a) Total 44 259 289 33 23 2,650 a Dead. It will be seen that oviposition continued for 20 days from IMay 9, a total of 2,650 ejjgs being deposited. Eggs deposited May 14 com- menced hatcliing June 21, an incubation period of 38 days. Two seed ticks from eggs de- posited May 14-25 were alive November 6, a pe- riod of more than 5 months from deposition. The fact that this pro- longetl survival included summer months shows remarkable vitality in the seed ticks of this species. Seed ticks of Margaropus annulatus seldom survive over 3 months in the summer. GULF COAST TICK. (Amblgomnm manilatinn Koch.) Synonyms : A. tig r in u m Koch, A. tenellum Koch, A. ru- bripes Koch, A. ovatum Koch, A. triste Koch, A. complanatmn Berlese (the prccx-ding on the authorityof Neumann), Dermacentor ocddentalis Marx of Niles (Morgan). This species was described by Koch in 1844 from ''Carolina," no host being given. Prof. H. A. Morgan calls our attention to the fact that it was referred to as Dermacentor occidentaUs Marx by Niles.« It .seems to be the common species along the Gulf coast of Louisiana and Texas. (See figs. 11, 12, 13, and PI. Ill, fig. 6.) It was taken by Mr. J. D. Mitchell of this Bureau from cattle, horses, dogs, and man in Cameron Parish, La., and Calhoun, Jackson, and Victoria counties, Tex. In the Marx collection there is a male specimen ll.-Ajnbhiomma maculattim: Mouth parts of fi'inalf. Greatly enlarged (original). aBul. Va. Agric. Exp. Sta., VII, No. 3, pp. 28, 29, PI. IV. CLASSIFICATION AND HABITS OK TICKS. 63 It soems (jiiite illoctod had been recorded as taken from cattle at Memphis, Tenn. probable that the animal from which the tick was c bred in the Coast sec- tion. There are also several specimens in the Marx collection taken in Texas. Neu- mann reports it from Paraguay, Uruguay, Brazil, Mexico, and in the Ignited States from California, Texas, and Tennessee, the latter based upon the tick before mentioned as collected at Memphis. He mentions 2 males and 1 female as being taken on a coleopteron, Cercus camj^estris, at Buenos Aires, Argen- tina. Laliille reports it from Argentine Re- public, where the fa- vorite host is the dog. He mentions the fact that it is used by the Indians as a leech in certain cases of inflammation. The male is especially large, much more so and more elongate than either A. cajennense or A. aineri- canum. Mr. Mitchell reports that while he has observed the sexes in close proximity on the animals he lias as yet to find them in coitu. He lias frequently noticed them to copu- late after being removed from the animal. However, in Argentina, Lahille states that several males are usually found attached in the immediate vicinity of each female. Mr. Mitchell states that on one oc- casion he found 7 females clustered f on a cow between the ear and the horn with no male near. In another case he found a cluster of 5 females on the neck of a dog with no male in the immediate vicinitv. He has also seen instances where as maculalum: itly enlarge Fu;. 13. — Amblyomma maculalum: Scutui fomale. Greatly enlarged (original). 64 NORTH AMERICAN FEVER TICK AND OTHER SPECIES. many as 5 males were located very close together without any females, and other cases on various parts in which both sexes were found together. This species is very firmly attached to the host. While Rhipiceplialus sp. can be removed easily A. ma culatwm can not be removed without evident pain. Attempts were made to rear the species upon dogs. On October 11 seed ticks were placed upon two small dogs. Eight were found attached on the 15th. For the first five or six days after attach- ment the seed ticks increase slowly in size, remaining of a light color ; then in a few hours they seem suddenly to engorge with blood. The color of the body becomes purplish and afterwards still darker. On the fifth day from placing seed ticks on the dogs 8 were found still light in color and 1 dark. On the sLxth day 2 were taken that had just detached themselves, leaving 2 dark and 4 light on the host. On the seventh day 3 were found to have dropped during the night ; 2 dropped and the remaining 1 engorged during the day. On Octo- ber 19 the eighth tick was found to have dropped during the night, making a mininmm period of 5 days and a maximum period of 8 days for attachment of larval stage. Several of the engorged larvie were kept on moist sand to molt, but shriveled and died. Th(> incubation period for eggs deposited from the 1st to the 11th of Se])t(Miiber varied from 26 to 81 days. Seed ticks from these eggs were still alive on March 1, 1907. LAND TITRTLE TICK. {Arnhlyominn tithirndaliini Marx.) This species was described by ]\Iarx in 1894 from specimens col- lected by Hubbard at Crescent City, Fla., from the Florida land tur- tle, Gopherus (Xerohates) polyphemus. Neumann reports a male specimen from Cuba. We have received 3 specimens collected in February, 1907, by Dr. A. W. :Morrill in Florida on a land turtle (Gopherus sp.), presumably the same as the host of the original specimens. BIBLIOGRAPHY. No attempt has been made to make this bibliography complete. In Section A, relating to the cattle tick of North America and the problems caused by it, the literature is scattered through many experiment station bulletins, veterinary journals, bulletins of the Department of Agriculture, and other publications. Only the more important are included. In Section B, relating to foreign disease- BIBLIOGRAPHY. 65 transmitting ticks, the literature is found for the most part in the governmental publications of South Africa and Australia, although recently important memoirs have been issued in Germany and France. As in the preceding section, we give only the more important publi- cations that are now available. For a very complete bibliography of this subject down to 1903, containing 221 titles, see A. Schmidt below. In Section C, relating to ticks as transmitters of human diseases, there is at present but a scanty literature. It is practi- cally all referred to by us. In Section D, relating more particularly to the classification of ticks, practically all of the works dealing with North American species are listed, together with the more impor- tant foreign publications. For a more extended list, see Salmon and Stiles, 1901, below. SECTION A. Relating to the North American Fever-Tick Problem. Butler, Tait. 1902. — The breeds of V)eef cattle and l)eef ])n)ducti()ii in Norlli Carolina N. C. State Bd. Agi-., bul. 23, no. 7. Pages 48-51 deal with: "Cattle tick an obstacle to tlic dcvclopincnt of the cattle industry." 1903.— Ileport of State Veterinarian in Rept. Comm. Agr. N. ('. for 1902, pp. 40-47. Regarding the cattle quarantine, the extermination of the cattle tick, losses from tick fever, and the tick an obstacle to the improvement of the quality of the cattle of the State. 1903.— The cattle tick and its relation to tlie cattle industry of North Cai-olina , no. 5, pp. .376-378, May. .\ report of progrcs.s in cxtenniiialion iiiul ii continuation of the two articles pub- lished in the above Journal October, l.S9(i, and January. IS'.tT. D.\LiiYMPLE, W. II.. II. .\. M<)U(iA\, and W. R. Dodson. 1898._Cattle tick and Texas fever a tly to the data furnished by Doctor Curtice in Texas Bulletin 24. 1899. — Immunization against Texas fever l)y Idood inoculaticm 7 Lewis, L. L. — Continued. 1899. — Texas fever. An ai'count of experiments <()kla. Asji-. Kx]i. Sia.. Iml. :','.!, pp. 28. figs. 5, May. 1900. — Means of preventing Texas fever f tlie Sonthern cattle tick . 139-152. Froggatt, Walter W. 1901. — The fowl tick {Argas americanus Packard) K.v of Maryaropnx inicropiu.s. LiGNIERES, J. 1900. — La Triste/.a on Malaria bovine dans la Republicjue Argentine, pp. 1-172, pis. 14. LOUNSBI^RY, C. P. 1899. — The bont tick Amblyomma hchrpcMm Koeh di.sease." "Ticks and malignant, jaundice, ricks and heartwater," pp. 16-41. 1903. — Ticks and African coast fever pnuUruhiliix. ]:. ftimus, R. crrrlsi. and R. capensis is briefly outlined. 1904.— Transmission of African coasi fcvci- . pi>. 1-7, j)ls. :5. Reprint: Agr. Journal. ('a])c (iood IIoi)c, .\pril. 1904.— Report of the (iovcrinuenl Kiitomolot^nst for the Cape of (iood llo])e for 1903. Includes "ticks and malignant jaundice" and "ticks and lieartwater," "ticks and South African coast fever," pp. 11-45, pis. 7 1905.— Tests of substances for tick destruction <.'\gr. Journal Cape (iood Hope, vol. 2(i, ])p. 387-395, March. 1905.— Report of the Government Entomologist for the Half Year ended June 30, 1904. Contain.sa special report, "licks and Africancoast fever." pi). 1()--J.">. Mally, C. W. 1904.— Notes on the so-called paralysis tick. Lodes pUo.vis -5S0. Spirillosis of chickens and other I'dwis t nmsiiiif teil by A t-.w.s- inini(iln.'<. MOTAS. 1903.— The role of ticks in llie deveh.innent of carccag < ixot. Pcabody Academy of Science, pp. 1-14. Contains descriptions of following new species of American fonns: Ixodes per punc- Intus, unipunctata {=Amb'y')wma americanum), leporis-palustris {Hsemaphysalis), chordeilis, borin (-^ Mirgircpux anvnUit-us), hihronii, vnponenxis (P.. A.), albipictns (X. .V,), iiifiroliiiralns. cookri. 1873.— Descriptions of new insects. Aracluuda V . S. (W'ological Survey of M<.nt., Idaho, Wyo., Utah. 1872; pp. 740-741. Includes Ixodes bon'.i Kiley (= Mcrq-trdpiis nvmihitiis) and Argas americanus n. sp., with figures of (>aeh. Rn.EY, C. Y. 1893. — Rei)ort on a small collection of in.-^ects made during the Death Valley Expedition <'TT. S. D. A., ]5iol. Surv., N. A. Fauna, no. 7, Part II, }). 252. Lists spven si)ecies of Ixodida — determined by Doctor Mar.x. Salmon, D. E.. and Ch. W. Stilks. 1901. — See al)ove. Say, Thomas. 1821. — An account of the arachnides of the United States !>, 73, 74 ^A. miniatus 42 - habits 42 miniatus. haljits, life history, synonym 42-45 transmitter of spirillosis of fowls 42, 71 persicus, bibliographic reference 71 sanchczi. habits 42 in Arizona and Now Mexico 73 spp. , effects of bites 70 transversa, in Galapagos Islands 73 78 INDEX. Page. Argasida\ habits 41 table (if genera 40 ArinadilUdium riilgatr. eating eggs of cattle tirk 36 Arpagostoma. ( See Ticks.) Ass. host of Margaropits annulatus 35, 39 Ornithodoros megnini 45 Bats, hosts of Ixodes ricinus 56 Beaver, ho.st of Dermacentor alhipidus 52 Birds, enemies of cattle tick 37, 39 hosts of Argas 42 Argasi(la> 41 Ixodes ricinus 56 sea. hosts of Coratixodes - 54 Boophihis annulatus=Margaropus annulatus 9 aastralis, in Philippine Islands : 69 =;Margaropus 9 Bufo ugiiu, host of Ambhjomma cdjennense 61 Capybara. (See Ilydrocharrus capybara.) Cariacus canadensis, host of Dermacentor albipictus 51 Cat . host of Ixodes cookei and /. ricinus 56 Maryaropus ayinulatus 34, 68 wild, liosl of Dermacentor bifarcutiis 50 Ixodes ricinus 56 Cattle, hosts of Atriblyotnuia americanum 59 cajennense 61 mac'ulatum 62 Chrysomyia macellaria 12 Dermacentor occidentalis 51 / variabilis 50 Ixodes ricinus 56 Ornithodoros megnini 45 infestation by cattle tick affected by ration 35-36 tick. (See Tick, cattli', and Margaropus annulatus.) Ceratixodes, structure and hosts 54 Cercns cavipestris, host of Amhhjomma maculatuni 63 Chalcidoid, with remains of cattle tick, probabh' jiarasite of dipieroii 36-37 Chicken. {See also P'owls. ) liouse. occurrence of Dermacentor parumapirtus 50 Chrysomyia macelhiriu. attack on cattle following that of tick 12 Deer, host of Atjibh/omina americanum 59 l>irmacd.s srupularis 57 Margurnpus (innulatus ' -^4, 39 Dcrmncciitor (intcriniiiuui author.'^, not Linn;vus,=7>. rnriabilis 50 in ( 'olorado 73 { variabilis) Curtice^D. occidentalis 51 (dbipiclus. distribution and hosts 51-52 Packard (Am. Nat., and Guide;, D. rcticulatus Salmon and Stiles (in part) a synonym 50 bifurralus. on wild-cat 50 clectus^D. variabilis 49, 50 nigroiinealus, in United States 50 INDEX. 79 Dermacentor nilens, distribution and hosts 52 Occident alls, distribution, hosts, sjmonjTns 51 Neumann, D. reliculatvs Sahnon and Stih's (in part) a synonym 49-50 '^[les=^ Amblyovimo indculdtiim •)2 transmitter of Rocky Mountain spotted fever 72 )>(inivt(ij>ertus, in a chicken house and on man 50 reticulutus Fabricius, not yet found in United States 50-51 Salmon and Stiles (in part)=Z). albipictits 50 Salmon and Stiles (in part)=i). ocddenlalis 49-50, 51 species in United States, structure 49-50 variabilis, habits and life history 50 in Florida 73 synonyms 50 variegatus, listed from United States liy Salmon and Stiles 49 Dicranocenis furcatus, host of Amblyomma tiwlli /unu-tuni 58 Dipteron, probable parasite of cattle tick 37 Dipterous larva>, enemies of cattle tick 3() Disease, human, transmission by ticks, bibliography 72 possilile transmission by Aniblyonniid mjennense til Denuaceiilor alhipidus 52 transmission l)y foreign ticks, bibliography G9-72 ticks 40 Dog, host of Ambhjonivia nmericanum 59 cajennense 61 maculatutn 50, 62 Dermacentor variabilis 50 Ixodes ricinus 56 scapularis ' 50, 57, 58 Mdrgaropus annulatus 34-35 Ornithodoros viegnini 45 Rfnpicephalus sp 47-48, 50 Dove. (See Zenaidura macroura.) wild turtle, host of Argas sanchezi 42 ' • Elk . " " (See Cariacus canadensis . ) Feed-lot system for eradicating cattle tick ;'>7-:'.8, (57 Felis pardalis, host of Ixodes ricinus 56 Ferret, host of Ixodes ricinus 5() Fever, African coast, of cattle, transmission l)y live species of Rhi])ic('phalus. . 48, 70 human, transmission by ticks 72 in cattle, said to be produced l)y Ainbh/oiniiui cajennense 61 Rocky Mountain spotted, transmission by Dermacentor occidentnlls 72 splenetic. {See Fever, Texas. ) Texas, losses 1 1-12 may it be transmitted by Ixodes ricinus? 57 transmission by cattle tick ( Margaropus annulatus) .... 10, 11-12, 40, ()9 " Fire-ant. ' ' (See Solenopsis geminata. ) * Flea, jigger. (See'Sarcopsylla penetrans.) Flooding. (iSee aZso Submergence. ) effect on seed ticks of cat th- t ick 24-25- Fowls, enemies of cattle tick 37, 39 Fox, host of Ixodes cookei and /. ricinus ,,.,,..,,,, ,'!!. 56 Freezing, (^ee Temperature.) 80 INDEX. Page. Goat, host of Amblyomina americanum 59 Ixodes cookei and /. ricinus 5() Gonixodes rostralis^Hsernaphysalis leporis-palustris 53 Gophenis polyphemus. host of Amblyornma tuberculatum 64 Ornithodoros furicata 4(i sp., host of Amblyornma tuberculatum (M Greasing, method of eradicating cattle ticks 07 Guinea pig, not a host of Margaropus annulatiis 34 Hxmaphysalis chordeilis, in United States 53 condnna, in United States 53 leachi, transmitter of malignant jaundice* of dogs 53 leporis-palustris, habits, synonym 53-54 structure and United States species 52-53 Hand-picking, method of eradicating cattle ticks 67 Hares, hosts of Hsemaphysalis leporis-palustris 54 Ixodes ricinus 56 Heartwater, in cattle, sheep, and goats, transmission l)y Amblyomma hebraeum. 58 Hedgehog, host of Ixodes ricinus • 56 Hog, host of Amblyomma americanum 59 Ornithodoros turicata 46 Horse, host of Amblyomma americanum 59 rajennen-se 61 maciilatum 62 Dermaccntor nitens 52 occidentalis 51 Hirmaphysalis leporis-palustris 53 Ixodes ricinus 56 Margaropus annulatus 35, 39 Ornithodoros megnini 45 Host relations of ticks 12 Houses, occurrence of Argas sanchezi 42 Hydrochserus capybara. host of Amblyomma cajennense 61 Insecticides, resistance of Argas miniatus • 45 Ixodes albipictus Packard (Am. Nat. & Guide )=Dermar£ntor albipictus. Packard (1st Peabody Acad. Rept.)^=I)ermacentor variabilis. . . 50 reference to original description 74 americanus, reference to original description 73 angustus, in United States 55 annulatus= Margaropus annulatus 74 reference to original description 74 arcticus, in United States ' 55 ■ bibronii, reference to original description 74 bifurcatus=Dermacentor bifurcatus 50 horealis, bibliographic reference. 73 bons, bibliographic references 74 = Margaropus annulatus 74 brunneus, in United States 55 cali/orniais, in United States 55 chordeilis. reference to original description 74 cookei, hosts, synonyms 55-56 reference to original description 74 crenatum = Amblyomma cajennense 60, 74 • reference to original description 74 INDEX. 81 Page. Ixodes cruciarius=I. cookei 55 reference to original description 73 dentalus, in United States 55 diver sifossus, in New Mexico 73 erraticus, reference to original descrii)ti(in 74 fimbriatus^ Ixodes borealis, male 73 frontalis, in United States 55 fuscous ifuscus), reference to original description 74 fuscus. in United States 55 hal)its 55 herrer;iR= Amblyomma americanum (iO hexagonus S. & S.=I. cookei 55 var. longispinosa= I. cookei 55 inchoatiis, in United States 55 leporis-palustris=IIscmaphysalis leporis-palustris 74 reference to original description 74 naponensis, reference to original description 74 ni(]rolineat\is=Dermacentor nigrolineatus 50, 55 reference to original description 74 (?) odontaLgise= , reference to original description 73 orbiculatus= Amblyomma americanum (?) 74 reference to original description , 74 perpunctatus, reference to original description 74 pilosus, bibliographic reference 71 drying up of engorged females in captivity Ijefore ovipositing. . . 55 plumbeus ( ?) , longevity of larvae 55 punctidatus=Dermacentor variabilis (?) 50, 74 reference to original description 74 quinquestriatus=Dcrmacentor variabilis 50 reference to original description 73 re.duvius=I. ridnus 70 ricinus, bibliographic references (17, 70, 72 connection with "louping ill" of sheep only accidental 56 habits and life history 56-57 in Santa Cruz Mountains, California 58 may 't transmit Texas fever in United States ? 57 oviposition process 1(5 transmitter of European piroplasmosis of catth^ 57, (J8 type of genus 54 robertsoni= Dermacentor variabilis • 50 reference to original description 73 scapularis, drying up of engorged females in captivity Ix'forc ovipositing. 55 habits 57-58 in Florida 73 on dog 50, 57, 58 reference to original description 74 sculptus, distribution and host 58 species in United States 55 sp., from Arizona 73 structure in genus 54 unipunctata=Amblyo)nina aincricniinni 74 reference to original description 74 5795— No. 72—07 6 82 INDEX. Page. Ixodes urise, in United States 55 variabilis^Dermacentor variabilis 74 reference to original description 74 Ixodidee, subfamilies and genera 46 table of subfamilies and genera 40 Ixodinse, structural character and genera 46 structure of genera 54 table of genera 41 Ixodoidea. (SeeTu-ks.) "Jackdaw." (See Quiscaliis major inacronriis.) Jaundice, malignant, of dogs, transmission l)y Hxmuphysnlis icarlii 53 Jigger flea. (See Sarcopsijlla penetrans.) Kingbird. (See Tyrannus tyrannus.) Leech, use of Amblyomma maculatum ])y South American Indians. 63 Lizards, hosts of Ixodes ricinm 56 Llama, host of Ornithodoros turicata 46 Lepns callotis, host of Dermacentor variabilis 50 palnstris, host of Ilieinaphysalis leporis-paliistris 53 sylvatieus, host of Ixodes rxeinus 56 Longevity of Argas miniatns 44-45 Ixodes 55 Ornithodoros mcgnini 46 "Loujjing ill," of slieep, connection of Ixodes ririniis only accidental o9 Mammals, hosts of Amblyonuna americamun • 59 Argas 42 Argasida; 41 Man, host of Amblyonuna americanum 59 cajennense . 61 maailatwn 62 Argas 42 Dennaeentor oecidentalis 51 parumapertus 50 Ixodes rieinus 56 Margaropvs annulatus 35 Ornithodoros megnini 45 turieata 46 Margaropus unnalatits. (See also Tick, cattle.) habitat 49 host relations 34-35, 39 in Florida 73 New Mexico 73 Ixodes bovis a synonym 74 outranked as a pest, locally, by Amblyomma ameri- canum 59 placed in genus Rhipicephalus by Neumann and Ful- ler 47 transmitter of splenetic or Texas fever 40, 69 var. argenfina, habitat 49 aiistralis, habitat 49 M. microphis prol)ably a synonym 49 calcarata, habitat 49 caudata, habitat 49 INDEX. 83 I'age. Margarnpus atiniddtiis, v;ir. (hcolortilii.s, etc., sludii's l)y Loiinslmiy 10 luil)itat 19 viabilit y in eggs 15- 1 (i correct generic nanu' for cattle tick (Boophihis anntdatus) 9 habits and structure distinguishing it from Rliipiccphahis 47, 49 micropliis, antiheliotropism 34 bil)liograpliic reference 70 genital apparatus 14 locomotion M probably= M. annulatus \ar. aiialralix 49 reattachment to host L'9 Marmot. (See also Arctomys monax.) host oi Ixodes cookei 56 Mice, hosts of Ixodes ricinus ^ 50 probable enemies of cattle tick '.M Mink. (See also Putorius vison. ) host of Ixodes ricinus 5G '"Mostacilla,"' Guatemalan name for young of Anihlj/omnid cajennense (il Mule, host of Amhlyomma americanum 59 Ixodes ricinus 50 Margaropus annulatus 35, 39 Opossum, host of Ixodes ricinus 50 Orniihodoros americanus=0. megnini, adult 73 habits 45 megnini, habits 45-40 Ornithodoros americanus and RJiijnrJiopriniii spiuosum synonyms 7;i movbata, bibliographic reference 72 enemies 37 transmitter of human tile of genera 40-41 Rhipkephaliis uppendiadatus, bibliographic reference 71 bursa americamis, reported from Jamaica 47 capensis, bibliographic reference 71 decoloratus, transmitter of spirillosis in cattle 72 evertsi, bibliographic reference 71 habits and structure distinguishing it from Margaropus 47, 49 sanguineus (Ann. Rpt. Bur. Animal Industry f. 1905, p. 35 1 = Rhipicephalns sp. of j)resent bulletin 48 in Panama 47 simus, bibliographic reference 71 sp., habits and life history ^. . . '. 47-49 in Colorado 73 on dog 50 same as R. sanguineus in Ann. Il])t. liur. Animal Industry 1. 1905, p. 35. 48 undetermined species from Colorado and Porto Rico 47 Rhynchoprium spinosum=Ornithodoros megnini. nymph 46, 73 Roebuck, host of Ixodes ricinus 56 Sarcopsylla penetrans, introduction into Soutli Africa 46 Screw-worm fly. (See Chrysomyia macellaria.i Sheep, host of Dermacentor occidentalis 51 Ixodes cookei and /. ricinus 56 Margaropus annulatus 35, 59 Ornithodoros megnini 45 Skunk, host of Ixodes cookei 56 Snake, Ornithodoros turicata in burrow 46 Soiling system, for eradicating cattle tick. {See Feed-lot system. ) Solenopsis geminata, enemy of cattle tick 36 Sp(>rmophile, host of It odes cookei 56 S})irillosis of fowls, transmission by Argas miniatus 42 Spirillum (Spirachsete) obermeien, prol)able cause of human tick fever 45 Splenetic fever. {See Fever, Texas.) Squirrel, host of Amblyomma americanum 59 Ixodes ricinus 56 Stag, host of Ixodes ridnus 56 Steer, used in experiments on cattle tick 27 Submergence, in water, effect on engorged adult cattle ticks 32-33, 39 incubation of cattle tick 22, 39 Sunlight, direct, effect on adult cattle ticks ; 32 Tapir, host of Amblyomma nrultipunctum 58 INDEX. 85 rage. Temperal ufc. effort on engorged females of cattle t ick 31-32 seed ticks of cattle t ick 24-25 in relation to incubation of cattle lick 19-21 Texas fever. [See Fever, Texas. ) Tick, adobe. (See Argas sanchezi.) Australian. {See Boophilus australis.) black-legged. (See Ixodes scapularis.) blue, common, bibliographic reference 69 bont. (See Amblyomvia hebrseum.) castor bean, American. (See Ixodes cookei.) European. (See Ixodes ricimis.) cattle. (See also Margaropus annidatus.) adult female, description 31 male, description 30 stage 30-34 adults as affected l)y direct sunlight 32 submergence in water 32-33, 39 attachments of specimens to each other 35 bibliography ()5-()9 control. (See eradication methods.) descriptions of adults 30-31 development as affected by ration of host 35-36 on host 28-30 dropping from host 33 egg stage 15-23 eggs as affected by heat and cold 21-22 submergence in water 22, 39 indication of viability 15-16 number deposited 17 percentage hatching 23 engorged adults as affected by submergence in water 32-33, 39 continuous cold and heat 31-32 enemies 3()-37, 39 eradication, from United States possible 9 nicthods 37-39 most important factor 13 host relations - 34-35, 39 importance of knowledge of life history 9-10 incubation 17-23 period 17-21 infestation affected by ration of host 35-36 knowledge of variations of periods in life history esscmtial 13 lack in knowledge of local climatic variations and dissemination . 10 larval stage 23-30 nonparasitic period 23-2() parasitic period 27-30 life history 13-33 locomotion 33-34, 39 longevity of secnl ticks 25-26 losses 11-12 male, position on host with relation tf) female 30 molts of larval stages 28-29 most important factor from standpoint of control 13 86 INDEX. Pasre. Tick, cattle, nymphal stage 28-29 oN'iposition period 14-15 process 16-17 periods in life history upon which means of control are based. . 38 practical application of data 37-39 preoviposition period 14 previous work on life history 10 reattachment to host 29-30 seed ticks as affected by submergence in water 24-25, 39 longevity 25-26 tick stage 23-30 nonparasitic period 23-26 parasitic period 27-30 submergence as affecting eggs 22, 39 engorged adults 32-33, 39 sunlight as affecting adults 32 temperature as affecting engorged females 31-32 incubation 19-21 seed ticks 24-25 transmitter of Texas fever 10, 11-12 Cayenne. (See Amblyomvia cajennense.) dog, American. (See Dermacentor variabilis.) brown. (See Rhipicephalus sp.) elk. (See Dermacentor albipictus.) fever, human, bibliographic reference 72 t ransmission by Ornithodoros moubata 45 Norlh American. (See Margaropiin annnlatus and Tick, cattle. ) fowl. (S(>c also .l/Y/r;.s' miniatus.) bibliographic reference 70 Gulf coast. (Se(> Amblyomma maculalum.) horse, tropical. {See Dermacentor nitens.) land turtle. (See Amblyomma tuberculatum..) lon(> star. (See Amblyomma americanum.) net. (See Dermacentor occidentalis.) paralysis. (See Ixodes pilosus.) rabbit. (See Hsemaphysalis leporis-palustris.) s(;ulptiu'ed. (See Ixodes sculptus.) spinose ear. (See Ornithodoros megnini.) turicata. (See Ornithodoros turicata.) wood. (Se(> Dermacentor variabilis.) Ticks, l)ibliography 65-75 castor bean . ( See I xod es . ) classification and distribution, bibliography 73-75 habits 40-64 foreign, that transmit disease, bibliography 69-72 graphic table for separation of families and genera, from Lahille 41 habits 40-64 host relations 12 key to families, subfamilies, and North American genera 40-41 • life history, general statement 12-13 transmitters of disease 40. 65-72 work by Lahille 10 "yearling," name given to ticks in nymphal stage 13 INDEX. 87 Page. Tie-rope, method of eradicating cattle ticks 67 Toad. {See Bufo agua.) Turtle, land. (See Gopherus ijolypheriias.) Two-field method of eradicating cattle ticks 67 Wapiti. (See Cariacus canadensis.) Weasel, host of Ixodes cookei 56 Wolf, host of Amblyomma americaniun 59 Woodchuck. (See Marmot and Arctomys monar.) Xerobates polyphemus. (See Gopherus polypheinus. ) "Yearling ticks," name given to ticks in nymphal stage 13 Zenaidura macroiira, host of Argas sanchezi 42 F. Mr '08 ^