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

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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 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 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. Dros