THE DIPTEROUS GENUS DOLICHOPUS IN NORTH AMERICA. 21 



11. Third joint of fore tarsi more than half as long as second (Colorado). 



No. 154, coloradensis Aldrich 

 Third joint of fore tarsi just about half as long as second (California). 



No. 151, completus, new species. 

 Third joint of fore tarsi one-third as long as second (Wisconsin; Colorado). 



No. 157, amphericus Melander and Brues. 



12. Second joint of fore tarsi shorter, or at most scarcely longer than the two following 



joints taken together 13. 



Second joint of fore tarsi distinctly longer than the two following joints taken 

 together •. 15. 



13. Second antennal joint yellow (Washington) No. 198, plumosus Aldrich. 



Second antennal joint black 14. 



14. Third joint of fore tarsi yellow, fifth joint nearly as wide as long (Colorado; 



Idaho; Washington) No. 153, sufflavus, new species. 



Third joint of fore tarsi blackish, fifth about half as wide as long (Colorado; New 

 Mexico) .... No. 149, speeiosus, new species 



15. Third joint of fore tarsi infuscated at apex (Wisconsin). 



No. 157, amphericus Melander and Brues. 

 Third joint of fore tarsi wholly yellow 16. 



16. Third joint of fore tarsi more than half as long as second (Colorado). 



No. 154, coloradensis Aldrich. 

 Third joint of fore tarsi scarcely half as long as second 17. 



17. Second joint of fore tarsi two thirds as long as first (Colorado; Wisconsin). 



No. 157, amphericus Melander and Brues. 

 Second joint of fore tarsi scarcely half as long as first (Idaho; Washington). 



No. 153, sujflavus, new species. 

 Second joint of fore tarsi nearly or quite as long as first (Colorado; Wyoming). 



No. 152, aeratus, new specie'?. 



1 8. Middle basitarsi fringed with black hairs on both sides 19. 



Middle basitarsi plain, not fringed 20. 



19. Middle tibiae nearly t\vice as long as their femora (Massachusetts; New Hamp- 



shire) No. 137, wheelerii Melander and Brues. 



Middle tibiae not over one and one-fourth times as long as their femora (wide- 

 spread in U. S. and Europe) No. 128, plumipes Scopoli. 



20. Hind femora ciliated with long black hairs; front violet (Eastern States). 



No. 113, margi^natus Aldrich. 

 Hind femora without, or with pale, cilia; front green 21. 



21. Hind femora ciliated with long whitish hairs on lower inner edge (Eastern States). 



No. 134, gracilis Aldrich. 

 Hind femora without cilia below 22. 



22. Hind margin of -wing with a conspicuous sinus between the tips of fifth and sixth 



veins (Eastern States) No. 131, fulvipes Loew. 



Hind margin of wing normal, rather evenly rounded 23. 



23. Hypopygium rudimentary, lamellae not developed; tips of hind tibiae wholly 



yellow (Illinois) No. 176, imperfectus, new species. 



Hypopygium normal, lamellae rather large; hind tibiae slightly infuscated at 

 tip (New Mexico) No. Ill, dorsalis, new species. 



24. Middle tarsi wholly deep black, the first joint thickened about as the hind basi- 



tarsi are (New Hampshire; Labrador) No. 129, dusypodus Coquillett. 



Middle basitarsi mostly yellow 25. 



25. Fore tarsi ornamented 26. 



Fore tarsi plain 38. 



