537 D75S82 >t,o^ THE NORTH AMEEICAN SPECIES OF DROSOPHH^A By a. H. STURTEVANT ^. Published by the Carnegie Institution of Washington Washington, 1921 CARNEGIE INSTITUTION OF AVASHINGTON Publication No. 301 Copies c were first issued MAR 3 1921 ^3 7 PRESS OF THE NEW ERA PRINTING COMPANY LANCASTER, PA. CONTENTS. Page Page I. Introduction 1[/ Systematic account—Continued Acknowledgments 2 Cladochteta 53 II. Behavior 4 Acletoxenus 54 Reactions to light 4 Blaesochaetophora 54 Reactions to gravity 4 Sinophthalmus 64 Olfactory reactions 4 Gitona 64 *v ^(Courtship and mating 5 Pseudiastata 55 Cross-copulation 9 Idiomyia. 55 Experiments concerning sexual Zygothrica 55 selection 9 Dettopsomyia 56 L Sex-recognition by the male. 10 Camilla 56 Duration of copulation neces- Stegana 66 sary 11 Zaprionus 58 III. Genetics 12 Pseudophortica 68 Mutations in species other than Leucophenga 59 D. melanogaster 13 Chymomyza 61 IV. Physiological studies 15 Mycodrosophila 62 Effect of humidity on pupae. ... 15 Scaptomyza 63 ^i Effect of temperature on length Drosophila 65 of life 15 Definition and distribution. 66 • 15 A. Nutrition Group (Sigmoides tj^pe) 70 Natural food of Drosophila larvse 16 4^ Group B. (Flora type) 72 Banana agar 16 Group C. (Dubia type) 73 V. Parasites and enemies of Drosophila 17 Group D. (Lutzii type) 74 Fungus parasites 17 Group E. (Prognatha type) . 75 Nematodes and mites 17 Group F. (Funebris type) ... 78 Hymenopterous parasites 17 Subgroup 1. Yellowish or Predacious enemies 17 reddish species 78 VI. Anatomy 18 v Subgroup 2. Blackish or Eggs 18 grayish species 93 Larvae 19^' Group G. Miscellaneous spe- Pupse 22 V cies 103 Structure of the imago 24 Names recorded from North Head 24 America but not included in Antennae 26 the previous treatment 105 Proboscis 26 Genera not here considered as Eyes 27 drosophiline 106 Thorax 27 XI. Geological history 107 Legs 29 XIL Geographical distribution 108 Wings 29 Nearctic region 108 Halteres or balancers 31 Neotropical region 112 Abdomen 32 Palaearctic region 114 VII. Chromosomes 39 Ethiopian region 115 VIII. Intraspecific variability 41 Oriental region 116 Secondary sexual characters. ... 44 Polynesian region 116 IX. Methods of collecting and pre- XIII. Species hybrid 117 serving Drosophilinae 45 XIV. Specific differences vs. mutational X. Systematic account 48 differences 119 Systematic position of the dro- Specific cases of parallelism be- sophiline flies 48 tween mutant characters and Genera of Drosophilinae 49 characters of wild species. ... 119 Aulacigaster 51 XV. Catalogue of described species of Curtonotum 52 Drosophilinse 123 Apsinota 53 XVI. Bibliography 134 Titanochseta 53 Index 143 111 LIST OF ILLUSTRATIONS. PLATES. Page Plate 1. Eggs of certain Drosophilinae 18 2. Scaptomyza adusta, male; Drosophila busckii, male; Drosophila funebris, female 64 3. Drosophila immigrans, male; Drosophila melanogaster, male; Drosophila me- lanica, female 84 TEXT-FIGURES. Pack Fig. 1. Anterior spiracle of third-stage larva of Drosophila funebris 20 2. Cephalopharyngeal skeleton of third-stage larva of Drosophila melanogaster. 21 21 .3. Cephalopharyngeal skeleton of third-stage larva of Drosophila funebris 4. Cephalopharyngeal skeleton of third-stage larva of Scaptomyza adusta 21 23 .5. Wing of a newly emerged Drosophila simulans that has not yet unfolded 5. Head of Drosophila robusta 25 7. Side view of thorax of Drosophila funebris (diagrammatic) 27 8. Wing of Drosophila melanogaster 29 32 9. 10, 11, 12. Ovipositor plates 34 13, 14, 15, 16. External male genitalia .17. ObUque section through spermatheca of Drosophila obscura, showing sperm inside 35 18-31. Spermathecae, magnified 250 diameters 36 32-43. Spermathecae, magnified 250 diameters 37 44. Diagram of chromosome groups found in the Drosophilinse (after Metz) 39 45. Head of male, Drosophila melanogaster 92 46. Head of male, Drosophila simulans 92 93 47. Drosophila obscura. Front leg of male, showing two tarsal combs 97 48. Drosophila viriHs. Head 105 49. Drosophila superba. Wing of type specimen IV THE NORTH AMERICAN SPECIES OF DROSOPHILA. I. INTRODUCTION. DrosopMla melanogaster Meigen {ampelophila Loew) has in recent years come to be widely used as a laboratory animal, especially in the study of heredity. Its short life-cycle, great productivity, and the ease with which it may be bred have been chiefly responsible for making it so popular for this purpose. These small flies have been used not only in the study of genetics, but also in investigations dealing with cytology, behavior, and various phases of physiology. It has also been found that several other members of the same group are amenable to laboratory life, and these species offer numerous additional possibili- ties for interesting experimental work, which are now beginning to be exploited. In view of these facts, it has seemed to the writer that a systematic review of the group would be desirable. No comprehensive study of the American forms has hitherto been made, so that our knowledge of the number of species and of their distribution and habits is very fragmentary. Furthermore, much of the published data on these points is unreliable, for the reason that different names have sometimes been applied to the same form, or different forms have been given the same name. Even when material has been identified by the same entomologist, there is a large possibility of inconsistency—and this applies to the writer's own determinations, for it is very easy to go astray when identifying pinned material. It is hoped, however, that a beginning has been made in the undertaking of bringing order out of something very like chaos. There was another, somewhat different, reason for making a sys- tematic study of the group. There has been a very large number of mutations discovered in the laboratory races of Drosophila melano- gaster Meigen, and also of other species, particularly of D. virilis Sturtevant. It seemed to the writer that it would be of considerable interest to get an idea of how these mutations compare with the differ- ences between wild species of Drosophila. The comparison is difficult to make without crossing species and comparing the inheritance of mutations with that of specific differences. But fertile species hybrids have so far not been obtained in the Drosophilinse, though many 1 2 THE NORTH AMERICAN SPECIES OF DROSOPHILA. attempts to get them have been made. It nevertheless seemed desir- able to discover whether the kind of differences that distinguish wild species are also the kind that are appearing in the laboratory as muta- tions. This question will be discussed in detail later in this paper. An attempt has been made to bring together here the more important available information concerning the North American members of the tribe Drosophilinse, and more especially the genus Drosophila. Exotic forms are discussed occasionally, but no extensive treatment of them has been possible. The data concerning the taxonomy, anatomy, development, distribution, and habits of the group are pre- sented as fully as available material will permit. Only a brief survey of the experimental work on the group has been attempted, but a bibliography of the experimental literature (with the more important papers on other lines) is presented. ACKNOWLEDGMENTS. This study has been made possible only by the favors and encourage- ment received from many difTerent sources. It would not be possible to mention here all those who have helped in one way or another toward the completion of the undertaking. There are, however, several to whom my thanks are especially due. I have made extensive use of the collections and library of the American Museum of Natural History, and am under great obliga- tions to Dr. F. E. Lutz and Mr. A. J. Mutchler for the pains they have taken to facilitate this use. Professor J. M. Aldrich and the late Mr. Frederick Knab, at the United States National Museum, and Mr. C. W. Johnson, at the Museum of the Boston Natural History Society, have given me every facility for studying the material under their care. Extensive loans of material from these three museums have been of very great help. Through the kindness of Mr. Samuel Hen- shaw and of Mr. Nathan Banks I have been enabled to examine the Loew collection in the Museum of Comparative Zoology at Harvard. Loans of valuable material have been received from Mr. C. W. Johnson, Professor J. M. Aldrich, Professor A. L. Melander, and Mr. S. W. Frost. Dr. J. C. H. de Meijere has sent me several European species, properly named, and these have been very valuable for com- parison with American forms. Mr. C. G. Lamb has supplied valuable information concerning several exotic forms about which I was in doubt. Local collections of considerable interest have been sent to me by several people. The most significant of these are the follow^ing: Dr. 0. L. Mohr, from Norway; Professor J. Arias, from Spain; Mr. W. S. Adkins, from Tennessee and elsewhere; Dr. R. R. Hyde, from Indiana and Maryland; Dr. F. Pajoie, from Indiana; Mr. D. E. Lancefield, from Oregon; Mr. C. T. Ramsden, from Cuba; Mr. L. L. INTRODUCTION. 3 Gardner, from California; Dr. F. N. Duncan, from Illinois; Dr. C. W. Metz, from Cuba, Isle of Pines, Jamaica, Louisiana, Florida, Cali- fornia, and Long Island. Dr. C. W. Metz has not only furnished many specimens from inter- esting localities, but he has furnished a large amount of very valuable data concerning the habits of many rare species. He and the writer collected together in Cuba, and the material recorded here from Havana, Santiago de las Vegas, Guareiras, and Aguada Pasajeros, unless credited to some other collector, is the result of our joint efforts. Dr. Metz and I have worked together for several years in attempts to breed various species in the laboratory, and a very large part of the success that we have had is due to his interest, energy, and ingenuity.