70 THE NORTH AMERICAN SPECIES OF DROSOPHILA. 



38. Genital arch of male with a hook-like posterior process (fig. 13); cheeks relatively 



narrow (fip. 45) melanogasler (p. 89) 



Genital arch with a cluiuslicll-liku pudterior process (fig. H); cheeks broader 



(fig. 46) simidans (p. 91) 



39. First oral bristle not twice second; not found in flowers funebris (p. 84) 



First oral bristle over twice second; live in flowers 40 



40. Brown ; costal index over 3.0 alfuri (p. 75) 



Black; costal index under 3.0 Irislani (p. 75) 



Not included in the above key: illola (p. 80 j. 



For purposes of description, the species of Drosophila listed below have 

 been separated into several groups. Of these the first three, typified by 

 D. sigtnoides Loew, D. florce Sturtevant, and D. duhia n. sp., respectively, 

 are fairly distinct. They might be separated as new genera if one were 

 inclined to multiply generic names. Perhaps the first two might be united 

 to form a single new genus. The groups typified bj^ D. lutzii Sturtevant 

 and by D. prognatha Sturtevant, respectively, are also fairly distinct, but 

 are harder to define satisfactorily than are the first three. Among the 

 miscellaneous species, D. opaca Williston and D. superba Sturtevant are 

 quite unusual, and each of these might serve as the type of a new genus if 

 one were so inclined. D. calloptera Schiner and D. guttifera Walker are 

 scarcely less anomalous. The other species, I think, may safely be con- 

 sidered as typical congeners of D. funebris Fabricius, the type. I have 

 been unable to even make a satisfactory arbitrary division of them into 

 groups. 



Group A. 



Prescutellars present; wings clouded; slender species; bristles and hairs brown; not 

 frequenters of fruit. 



Drosophila sigmoides Loew. 1872. Berlin, ent. Zeit., 16, 102. 



d^, 9 . Arista with about four branches above and" three below. Antennte yellowi 

 third joint brown. Front over one-third width of head, wider above; brown. Second 

 orbital about one-half other two. Second oral bristle less than half length of first. Carina 

 broad and flat; face yellow. Clypeus prominent. Cheeks yellow; their greatest width 

 about one-sixth greatest diameter of eyes. Eyes with short, fine pile. 



Acrostichal hairs in six rows; prescutellar bristles well developed. Mesonotum reddish 

 brown, grayish yellow between the dorsocentral rows. Scutellum grayish yellow. Pleurae 

 graj'ish brown. Legs yellow. Apical and preapical bristles on first and second tibiae; 

 preapicals on third. Bristles and hairs brown. 



Abdomen dull brown, no markings visible. 



Wings grayish, darker along anterior margin; blackish at tips of second, third, and 

 fourth veins and on both cross-veins. There is usually a clear spot between the second and 

 third veins, and another between the third and fourth. Posterior cross-vein distinctly 

 sinuate. Costal index about 4.0; fourth-vein index about 1.5; 5x index about 1.0; 4c 

 index about 0.7. 



Length body 2.3 mm.; wings 2.5 mm. 



Specimens examined: Cold Spring Harbor, New York (C. W. Metz); 

 Algonquin, Illinois (D. W. Coquillett); Plummer's Island, Maryland (A. K. 

 Fisher); Falls Church (Nathan Banks), Diggs (R. C. Shannon), Virginia; 

 St. Elmo (near Chattanooga), Tennessee (W. S. Adkins); North Carolina 

 (U. S. Nat. Mus.); Pickett Springs (near Montgomery, F. E. Watson), 

 Gulf crest, Kushla, Alabama; Piano (E. S. Tucker), type locahty (Loew 

 material), Texas. 



I have collected this form in southern Alabama by sweeping grass and 

 weeds. Attempts to get it to breed on fruit have not been successful. It 

 was not attracted to fruit that was exposed for several days in a small patch 

 of young plants of Solidago canadensis, from which D. sigmoides could be 

 swept at any time. The specimen from New York, however, was collected 

 by Dr. Metz on windfall apples. 



