AMERICAN DIPTERA. 215 



8. Thorax yellow in large part 9. 



Thorax wholly black 15. 



9. Head black 11. 



Head yellow 10. 



10. Head narrow tersus Coquillett. 



Head broad flavirostris Loew. \^ 



11. Thorax with black vitta 12. 



Thorax with no vitta 13. , 



12. Proboscis mostly yellow inesograinnms Loew.«^ 



Proboscis black ; wings elongate caligatus sp. nov. 



13. Front femora somewhat thickened 14. 



Front femora not thickened flavirostris Loew. 



14. Proboscis wholly black •.• • -Ijetus Loew. 



Proboscis yellow at base iilipexus sp. nov. 



15. Legs slender, femora subequal Ticarius Walker. 



Middle femora at least enlarged 16. 



16. Tibial spur wanting; posterior cross-vein nearly perpendicular 17. 



Spur of middle tibige present ; cross-vein oblique 19. 



17. Abdomen wholly shining; thoracic bristles yellow 18. 



Abdomen pollinose; some bristles black canus sp. nov.*^ 



18. Mouth-opening very large hians sp. nov. 



Mouth-opening normal iiiops sp. nov. 



19. Antennae wholly black 20. 



Antennae in part yellow 25. 



20. Tarsi strongly annulate 21. 



Tarsi uniform or at most weakly annulate 22. y 



21. Third antennal joint long, lanceolate seqiialis Loew.v/'^ 



Third antennal joint short, oval trivialis Loew female. 



22. Both third and fourth veins subparallel with axis of wings, abdomen not 



pollinose ■ • ■ • 23. 



Either third or fourth sinuous, bending backwards; abdomen pollinose. 



incurvus sp. nov.**' 



23. Hind metatarsi yellow, at extreme tip dark 24. 



Hind metatarsi uniformly dusky gravidas sp. nov.V 



24. Species 2 mm. long, wing 2 mm., arista equal to antenna.. .liastatus sp. nov. 

 3 mm. long, wings 5 mm., arista longer than antenna. . -caligatus sp. nov. 



25. Proboscis black 26. 



Proboscis yellow tenellus sp. nov. 



26. Front end of pleura to the posterior side of the front coxse, also lateral mar- 



gins of the metanotum, encroaching slightly on the pleura, opaque, 



gray pruinose (Alaska) gilvipes Coquillett. 



The smooth "plaga" much reduced iu size 27. 



27. Sixth vein not obsolete at the base 28. 



Anal cell incomplete ; tarsi annulate crassilemoris Fitch. >/ 



28. Middle tarsi of the male black, the front tarsi whitish, of the female all the 



tarsi annulate discifer Loew. 



Tarsi more uniform lateralis Loew. 



TKA.NS. AM. ENT. SOC, XXVIII. JULY, 1902. 



