AMERICAN DIPTERA. 285 



10. Thorax trivittate tridentala Coquillett. 



Tliorax not trivittate 11. 



11. Abdomen largely black 12. 



Abdomen largely yellow 16. 



12. Antennse black 13. 



Antennae fuscous at base 15. 



13. Shining ; abdomoi in part yellow 14. 



Abdomen wholly black olIiuN Walker. 



14. Tip of hind tii)ije black loi'ipediN Coquillett. 



Tip of hind tibiae yellowish gladiator sp. nov. 



15. Tip of femora black eudaiiiidas Walker. 



Tip of hind femora concolorous with rest, reddish abcirus Walker. 



16. Base of abdominal segments fuscous, rest yellow sordida Loew. 



Tip of abdominal segments blackish, rest yellowish longipes Loew. 



Whole insect yellow female of hiinnile Coquillett (?). 



17. Cross-veins bordered with brown pceciloptera Loew. 



Cross-veins not bordered ... 18. 



18. Thorax with five vittte ; hind femora fuscous above inira Bigot. 



Thorax not vittate ; femora not darkened above 19. 



19. Abdomen yellow, with rather long yellow pile . . • ■ palli<la Loew. 



Abdomen fuscous, with short black hairs 20. 



20. Antennse yellow basally ; thorax opaque arillipes Loew. 



Antennae black ; thorax shining COloiiica Walker. 



21. Pile of thorax and at base of abdomen in part pale 22. 



Pile wholly black 31. 



22. Species of 3 mm. 23. 



Larger species of 5-10 mm 25. 



23. Stigma dark fuscous ; antennae black obeNa Loew. 



Stigma wanting ; antennae reddish at base 24. 



24. Abdomen more or less yellow coinpta Coquillett. 



Abdomen wholly black varipes Loew. 



25. Knob of halteres black ; abdomen largely shining 26. 



Halteres yellow ; abdomen opaque 27. 



26. Mesoiiotal hairs white coinautis Coquillett. 



Mesonotal hairs black bracliystoina Coquillett. 



27. Scutellum with 6 to 8 bristles; antennae black ravida Coquillett. 



Scutellum with fewer bristles ; antennae red basally 28. 



28. Dorsum of abdomen brown pollinose; scutellum with two bristles; legs of 



female ciliate, with short black scales. . . captiis Coquillett. 



Scutellum with 4 bristles ; legs not feathered 29. 



29. Pile of body luteous Aldrichii sp. nov. 



Pile of body white 30. 



30. Stigma brown, wings gray; abdomen blue-gray pollinose. 



avida Coquillett. 

 Stigma wanting, wings whitish; abdomen brown-pollinose. 



Isevicula Coquillett. 



31. Fourth vein incomplete; thorax evittate ; eyes of male contiguous (of the 



known males) 32. 



TRANS. AM. ENT. SOC, XXVIII. AUGUST, 1902. 



