36 THE NORTH AMERICAN SPECIES OF DROSOPHILA. 
any at all, and Aulacigaster leucopeza (fig. 18), in which three are 
present. As the figure shows, these are of a somewhat unusual type; 
and two of them are attached to a single duct. This is normal for 
the species, as it has been observed in specimens from Alabama and 
also from Illinois. 
b 
20 
22 
23 
24 21 
(if 27 
25 Be 
30 31 29 28 
Fics. 18-31.—Spermathece. Magnified 250 diameters. 18. Aulacigaster leucopeza. 
19. Leucophenga varia. 20. Chymomyza amcena. 21. Mycodrosophila 
dimidiata. 22. Scaptomyza graminum. 23. Drosophila affinis. 24. Dro- 
sophila busckii. 25. Drosophila caribbea. 26. Drosophila duncani. 
27. Drosophila funebris. 28. Drosophila guttifera. 29. Drosophila immi- 
grans. 380. Drosophila melanica. 31. Drosophila melanogaster. 
According to Wesché (1906), most of the non-muscid Diptera have 
three chitinized receptacles with three separate ducts, although none 
is seen in the Dolichopodide, Lonchopteride, and Phoride, and only 
