AMERICAN DIPTERA. 263 



6. Abdomen yellowish at base basalis Loew. 



Abdomen uuicolorous, dark 7. 



7. Stigma obsolete 8. 



Stigma at least fuscous 12. 



8. Legs fuscous to black 9. 



Legs paler 11. 



9. Thorax 4-vittate qua<Iri vittata Meigen. 



Thorax evittate 10. 



10. Thoracic hairs blackish ; halteres whitish ; veins pale- -leucoptera Loew.^ 

 Thoracic hairs pale ; halteres infuscated ; veins dark bella sj). nov. 



11. Abdomen opaque inacroplera Loew. 



Abdomen shining congregaria sp. nov./ 



12. Front metatarsi not thickened ; antennte at least three times as long as the 



head, its style twisted johnsoiii Coquillett. \r 



Male front metatarsi somewhat thickened; antennse shorter, the style 

 straight 13. 



13. Palpi black 14. 



Palpi testaceous 23. 



14. Knees more or less yellowish 15. 



Knees black 18. 



15. Wings blackish tristis Loew.^ 



Wings cinereous 16. 



16. Knob of halteres black miitabilis Loew. , 



Knob of halteres fuscous 17. 



17. Thorax vittate trivittata Loew.v 



Thorax evittate nugax sp. nov.v^ 



18. Thorax vittate 19. 



Thorax evittate 20. 



19. Pile of abdomen .vellow oana Coquillett. 



Pile of abdomen black baculifer sp. nov.'. 



20. Abdomen opaque iiiiicolor Loew. 



Abdomen somewhat shining 21. 



21. Wings dusky velutiiia Loew. 



Wings subcinei'eous 22. 



22. Thorax shining atra Loew. 



Thorax velutinous carboiiaria sp. nov.v 



23. Abdomen at base fuscous ... -baMalis Loew. 



Abdomen wholly black 24. 



24. Femora, except tip, black ; thorax with two obsolete vittse. 



breTipila Loew. 

 Femora more or less yellow ; thorax evittate 25. 



25. Knob of halteres black 26. 



Knob of halteres yellowish 27. 



26. All the femora testaceous gracilis Loew.v^ 



The hind femora not testaceous nigriTeiitris Loew. 



27. Pile of middle tibiie long seriata Loew. 



No long hairs on middle legs; second joint of front tarsi of the male not pro- 

 ceeding from the tip of the metatarsus Wheeleri Melander. s/' 



