THE DIPTEROUS GENUS DOLICHOPUS IN NORTH AMERICA. 15 



5. Hind tibiae blackened at tip 6. 



Hind tibiae wholly yellow or only slightly inftiscated at tip 15. 



6. Last joint of fore tarsi more or less compressed 7. 



Last joint of fore tarsi plain 9. 



7. First four joints of fore tarsi plain, fifth a very little compressed (Regina; Canada.) 



No. 94, canadensis, new species. 

 Fourth and fifth joints of fore tarsi distinctly compressed 8. 



8. Hind femora with long yellow cilia below (Alaska; Europe). 



No. 119, plumitarsis Fallen. 

 Hind femora without cilia (Eastern States) No. 115, albicoxa Aldrich. 



9. Hind femora ciliated with long yellow hairs below 10. 



Hind femora without cilia below 11. 



10. Costa with a small knot-like enlargment at junction of first vein (Ontario). 



No. 104, flaviciliaius, new species. 



Costa a little enlarged at junction of first vein, gradually tapering to its tip (Maine; 



New York; Labrador) No. 107, serrafus, new species. 



11. Last four joints of fore tarsi of nearly equal length, each a little narrowed at base 



(widespread) No. 92, indigena, new species. 



Second joint of fore tarsi distinctly longer than third; last four joints cylindrical, 

 not narrowed at base 12. 



12. Third antennal joint long, acutely pointed, arista nearly apical; hypopygia) 



lamellae large (Massachusetts) ^ No. 95, acuius, new species. 



Third antennal joint obtusely pointed or rounded at tip, arista inserted 

 near the middle of the third joint; lamellae of moderate size, not large 13. 



13. Hind femora with a lower row of little black hairs on inner side, so that when 



seen from below there are two rows of little black hairs with a glabrous space 



between them on lower edge (eastern) No. 91, brevimanus Loew. 



Hind femora with the lower row of little hairs on inner surface yellow and 

 very delicate 14. 



14. Fifth joint of fore tarsi yellowish; the yellow hairs on lower inner edge of 



hind femora nearly one fifth as long as the width of the femora; costa with- 

 out an enlargement at tip of first vein; third antennal joint twice as long 



as wide No. 89, socius Loew. 



Fifth joint of fore tarsi black, not at all paler than those preceding it; hairs on 

 lower inner edge of hind femora very short; third antennal joint one and a 

 fourth times as long as wide; costa with a small but distinct knot-like en- 

 largement at tip of first vein (eastern). No. 90, socius, var. gladius, new variety. 



15. Hind tarsi entirely black or very nearly so 16. 



Hind tarsi yellow at base 23. 



16. Hind femora without cilia below 17. 



Hind femora ciliated on lower inner edge 18. 



17. Fore tarsi twice as long as their tibiae, with last joint much compressed (Hudson 



Bay Territory) No. 143, nudus Loew, 



Fore tarsi one and one-fourth times' as long 'as their tibiae, their last joint 

 only slightly widened (Regina; Canada) No. 94, canadensis, new species. 



18. None of the joints of fore tarsi compressed, but the last four joints narrowed 



at base (Maine; New York; Labrador) No. 107, serratu-s, new species. 



Last joint of fore tarsi much compressed, lamelliform 19. 



19. Enlarged last joint of fore tarsi with a white reflection on the outside (east- 



em) No. 188, palaestricus Loew. 



The same without a white reflection 20. 



20. Fore tarsi twice as long as their tibiae 21 . 



Fore tarsi one and a half times as long as their tibiae 22. 



