THE DIPTEROUS GENUS DOLICHOPUS 11^ N^ORTH AMERICA. 13 



All femora black, slightly yellowish at extreme base and tip; posterior pair 

 ciliated below with long white hairs, without long hairs above (Washington). 



No. 31, melanderi, new species. 

 9. Fore tarsi nonnal; third antennal joint nearly three times as long as wide; 



arista' very short, subapical (Indiana) No. 40, angusticornis, new species. 



Fore tarsi with its joints narrowed at base; third antennal joint rather small, 

 normal (Washington) No. 42, litoralis, new species. 



10. Middle femora mostly yellow 11. 



Middle femora largely or wholly black 17. 



11. Hind femora black 12. 



Hind femora mostly yellow 13. 



12. Last two joints of middle tarsi compressed and fringed (Alaska; Idaho; New 



Mexico; Utah) No. 66, raripes Coquillett. 



All tarsi plain (Idaho) No. 51, sedulus, new species. 



13. Hind femora wholly yellow (Colorado; Idaho; Nevada; Utah). 



No. 62, amnicola Melander and Brues. 



Hind femora black at tip, at least above; middle ones with a black streak 



above or below 14. 



14. Hind femora black above on whole upper edge 15. 



Hind femora black at tip (Labrador) No. 61, hryanti, new species. 



15. Costa with a knotlike enlargement at tip of first vein (Alaska). 



No. 60, solidus, new species. 

 Costa not or scarcely at all enlarged at tip of first vein 16. 



16. Hypopygium small, its lamellae yellowish; posterior femora without cilia below 



(New Hampshire) No. 65, brevicauda, new species. 



Hypopygium normal in size, its lamellae whitish; hind femora with a few white 

 hairs below near the tip (New Hampshire ; Colorado ; Alaska) 



No. 44, xanthocnemus Loew. 



17. Middle femora infuscated at base, gradually becoming yellow toward their 



apex 18. 



Middle femora black, sometimes yellow at tip 22. 



18. First antennal joint long and slender (Alaska) No. 64, humilis, new species. 



First antennal joint short as usual « 19. 



19. Hypopygium short, its lamellae yellowish (New Hampshire) 



No. 65, brevicauda. new species. 

 Hypopygium of normal size, its lamellae whitish 20. 



20. Hind femora ciliated below near the tip with a few white hairs 21. 



Hind femora without cUia below (Idaho) No. 51, sedulus, new species. 



21. Cilia of the calypters black (New Hampshire; Colorado; Alaska). 



No. 44, xanthocnemus, new species. 

 Cilia of the calypters yellowish (Washington) No. 42, litoralis, new species. 



22. Hind femora ciliated with long hau's below 23. 



Hind femora without cilia below, or with the cilia very short 28. 



23. Hind femora ciliated with long black haii-s 24. 



Hind femora ciliated with pale hairs 25. 



24. Wings with a conspicuous brown cloud in front, opposite the cross vein (Colorado.) 



No. 47, partitus Melander and Brues. 

 Wings without a brown cloud (eastern) No. 45, albiciliatus Loew. 



25. Hind tibiae swollen, subfusiform, mostly black (South Dakota; Colorado; 



Idaho ; Wyoming) No. 27, conspicuus, new species. 



Hind tibiae slightly enlarged at tip, yellow with sharply defined black tips.. 26. 



26. Hind femora ciliated with a few long white hairs below; fore tarsi plain; costa 



with a small knot-like enlargement at tip of first vein (New Hampshire; 



Colorado; Alaska) No. 44, xanthoaiemus, new species. 



Hind femora with short cilia below 27. 



187329—21 2 



