AMERICAN DIPTERA. 285 



10. Thorax trivittate tridentata Coquillett. 



Thorax not trivittate 11. 



11. Abdomen largely black 12. 



Abdomen largely yellow 16. 



12. Antennae black 13. 



Antennae fuscous at base 15. 



13. Shining ; abdomen in part yellow 14. 



Abdomen wholly black oIliuN Walker. 



14. Tip of hind tibiaj black loripedi!!« Coquillett. 



Tip of hind tibiae yellowish gladiator sp. nov. 



15. Tip of femora black eiidaiuidas Walker. 



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



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



Tip of abdominal segments blackish, rest yellowish lougipes Loew. 



Whole insect yellow female of Iiiiinile Coquillett (?). 



17. Cross-veins bordered with brown pceciloptera Loew. 



Cross- veins not bordered 18. 



18. Thorax with five vittae ; 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. Antennae yellow basally ; thorax opaque arniipes Loew. 



Antennae black ; thorax shining colonica 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 obesa Loew. 



Stigma wanting ; antennae reddish at base 24. 



24. Abdomen more or less yellow compta Coquillett. 



Abdomen wholly black Taripes Loew. 



25. Knob of hal teres black ; abdomen largely shining 26. 



Halteres yellow ; abdomen opaque 27. 



26. Mesonotal hairs white comantis Coquillett. 



Mesonotal hairs black braeliystouia 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- • • caplllH Coquillett. 



Scutellum with 4 bristles ; legs not feathered 29. 



29. Pile of body luteous Aldricliii 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. 



IsBTicula Coquillett. 



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



known males) 32. 



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



