Book _ iBl^.!!/! UNITED STATES DEPARTMENT OF AGRICULTURE jn-^^wt. BULLETIN No. 1028 Contribution from the Bureau of Entomology L. O. HOWARD, Chief Washington, D. C. PROFESSIONAL PAPER March 13, 1922 APANTELES MELANOSCELUS, AN IMPORTED PARASITE OF THE GIPSY MOTH. By S; S. Ceossman,' Entomological Assistant, Gipsy Moth and Brown-Tail Moth Investigations. CONTENTS. Page. Introduction 1 Part I. — Description and life his- tory 2 History 2 Distribution in Europe 3 Description of species 3 Methods used in biological work- 4 Life history 5 Seasonal history 11 Feeding of parasitized larva» versus nonparasitized larvse 12 Longevity experiments 12 Hosts of A. mclanoscelus 12 Part II. — Introduction and estab- lishment 14 European work 14 Comparison of seasonal history in Sicily and New England 15 Page. Part II. — Introduction and estab- lishment — Continued. Abundance of A. melanoscelus in Sicily 15 Secondary parasitism in Sicily_ 16 Colonization in New England 16 Methods used to obtain material for colonization 18 Success of colonies and distribu- tion of A. melanoscelus 21 Dispersion 22 Secondary parasitism 23 The value of A. melanoscelus as a gipsy moth parasite 23 Abundance of A. melanoscelus in New England 24 Conclusion 25 INTRODUCTION. From the year 1905 to December 1, 1911, the State of Massachu- setts and the Bureau of Entomology, United States Department of Agriculture, shared the expenses involved in cariying on an investi- gation of the natural insect enemies of the gipsy moth {Porthet'i'ia dispar L.) and the brown-tail moth {Eicproctis chrysorrhoea L.) in Europe and of the introduction of parasites of these insects from 1 The writer wishes to acknowledge the efforts of all those who have been connected with the Gipsy Moth Laboratory during the period covered by this report, who have assisted at various times in gathering and recording some of the data from which this Ijulletin has been prepared. H. A. Preston and C. E. Hood took most of the photographs and W. N. Dovener made the drawing of the adult Apanteles. He wLshes especially at this time to express his appreciation and thanks to A. F. Burgess, who has general direction of the work, for his help and suggestions. 73070°— 22 1 2 BULLETIN 1028, U. S. DEPARTMENT OF AGEICULTURE. their native homes to New England. A comprehensive report^ of this work from its beginnings through 1910 has been published in Bulletin 91 of the Bureau of Entomology. Among the imported parasites which are now established is Afanteles melanoscelus Ratz., a double-brooded parasite of the gipsy moth. The following report has been prepared in two parts: Part I contains the description of the species and its life historj^, and Part II takes up its introduction and establishment. PART I.— DESCRIPTION AND LIFE HISTORY. HISTORY. The insect was described by Ratzeburg^ in 1844 very briefly as follows (translation) : Microgastcr ntelanoscelu