SYSTEMATIC ACCOUNT. 67 



Nearctic Species of Drosophila. 



1. Acrostichal hairs, just in front of dorsocentral bristles, in six rows 2 



Acrostichal hairs in eight rows -. 20 



2. Facial carina very small, absent or very narrow below; second oral bristle not 



over half length of first 3 



Carina broad below 5 



3. Yellow; third antenuul joint large, with long yellow hairs; fourth-vein index 



under 2.0 duncani (p. 86) 



Blackish; tliird antennal joint as usual; fourth-vein index over 2.0 4 



4. Costal index 3.0 or over; a comb of stout black bristles on inner side of basitarsal 



joint of first leg of male affinis (p. 94) 



Costal index under 2.5; no tarsal comb alabamensis (p. 102) 



5. Wings with about thirteen small dark spots along veins; mesonotum yellow, 



striped with reddish brown; first two to four oral bristles nearly equal. 



guttifera (p. 103) 

 Wings much clouded; posterior cross- vein sinuate; small prescutellars present. 



sigmoides (p. 70) 

 Wings clear, or slightly clouded along cross-veins or tips of longitudinal veins ... 6 



6. A pair of presutural acrostichal bristles present; yellowish-brown species. 



pulrida (p. 81) 

 No presutural acrostichals 7 



7. Second orbital about half length of first; only one large oral bristle; yellow species; 



2.7 mm. long ordinaria (p. 86) 



Second orbital less than half length of first 8 



8. Costal index not more than 2.1; Neotropical species, found in southern Florida. . . 9 

 Costal index not less than 2.5 10 



9. Reddish-brown species; bristles and branches of arista short; Uves in flowers. 



lutzii (p. 74) 



Yellow; bristles and arista as usual; lives in fruit ivillistoni (p. 89) 



10. Ground-color of mesonotum blackish or grayish, not at all jellowish 11 



Ground-color of mesonotum yellow, or reddish brown 16 



11. Second oral bristle over half length of first; fourth-vein index about l.S 12 



Second oral less than half first 13 



12. Carina broad; costal index about 3.0; 2.7 mm. long virilu (p. 97) 



Carina narrow; costal index about 4.0; 1.5 mm. long pseudomelanica (p. 94) 



13. Carina distinctly sulcate; mesonotum grayish polUnose, irregularly marked with 



reddish brown ; 3 mm. long sidcata (p. 96) 



Not as above 14 



14. First coxae black below; 2.5 mm. lung see robustu, below 



First coxae brown ; 2 mm. long 15 



15. Mesonotum blackish brown; " cheek " one-sixth greatest diameter of eye. 



melanica (p. 95) 



Mesonotum brownish black; " cheek " one-third diameter of eye. inelanissima (p. 95) 



16. Wings clear; abdomen banded; only one large oral bristle melanderi (p. 82) 



At least posterior cross-vein slightly clouded 17 



17. Reddish yellow; abdomen banded; Neotropical species found in soutliern Florida. 



cardini (p. 78) 

 Yellow, not reddish 18 



18. Abdomen with interrupted posterior dark band on each of first four segments, 



and a median anterior spot on third, fourth, and fifth segments. 



tripundata (p. 82) 

 Abdomen spotted, but without median spots 19 



19. Dull yellow; tips of longitudinal veins not clouded transversa (p. 81) 



Shining yellow; tips of second, third, and fourth veins clouded quinaria (p. 80) 



20. Carina minute; small prescutellars present; wings much clouded inversa (p. 71) 



Carina not minute; prescutellars not clearly differentiated; wings clear or with 



small clouds along veins 21 



21. Mesonotum yellow, with distinct blackish longitudinal stripes; second orbital 



nearly as long as third busckii (p. 77) 



Mesonotum hght gray, with numerous dark-brown spots; carina sulcate 22 



Mesonotum not distinctly marked 23 



