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 



.3. Cephalopharyngeal skeleton of third-stage larva of Drosophila funebris 21 



4. Cephalopharyngeal skeleton of third-stage larva of Scaptomyza adusta 21 



.5. Wing of a newly emerged Drosophila simulans that has not yet unfolded 23 



5. Head of Drosophila robusta 25 



7. Side view of thorax of Drosophila funebris (diagrammatic) 27 



8. Wing of Drosophila melanogaster 29 



9. 10, 11, 12. Ovipositor plates 32 



13, 14, 15, 16. External male genitalia 34 



.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 



47. Drosophila obscura. Front leg of male, showing two tarsal combs 93 



48. Drosophila viriHs. Head 97 



49. Drosophila superba. Wing of type specimen 105 



IV 



