ART. 23 TWO-WIXGED DOLICHOPODID FLIES VAN DUZEE 3 



13. One pair of femora more tliaii half black or greeu 14 



All femora yellow, tips of posterior pair may be broadly black 19 



14. All femora black or green, their tips may be yellow 15 



One or two pairs of femora largely yellow 18 



15. Face velvety black 15, velutina, new species. 



Face silvery white 16 



IG. Cilia of the calypters black (Alaska; Oregon; Washington; Idaho), 



11, albiventris Loew. 



Cilia of the calypters pale yellow 17 



17. Second and third abdominal segments largely yellow (New England; New 



Jersey; Montana; Idaho; Canada) 12, robusta Johnson. 



Abdomen with very indistinct yellow spots on second segment (Canada), 



14, bimaculata, new species. 



18. Fore femora black on upper and most of posterior surface; middle ones 



yellowish; hind pair blackened on apical half above (California), 



16, splendida, new species. 

 Fore and middle femora black with yellow tips ; hind ones with apical third 



black (New England) 31, obscura, new species. 



Fore femora black on basal half; middle ones on basal half of posterior 

 surface; hind femora black on more than apical third (Alaska), 



13, ciliata Van Duzee. 



19. Tips of hind femora black, at least distinctly infuscated 20 



Hind femora not, or scarcely darkened at tip 31 



20. Fore coxae almost wholly black 21 



Fore coxae yellow, sometimes considerably blackened at base 22 



21. Middle femora with a row of long black hairs on both anterior and pos- 



terior edges of lower surface (California) 21, californica, new species. 



Jliddle femora with one row of black bristles on the anterior edge of lower 

 surface, none on posterior edge (Ohio) 20, nigricoxa, new species. 



22. Second joint of hind tarsi not very much shorter than first, which has only 



the usual short hair 23 



Second joint of hind tarsi not, or scarcely half as long, as the first, which is 

 furnished with long bristles 29 



23. Fore and middle femora with conspicuously longer yellow hairs below 



(Middle and Eastern States; Canada) 23, calceata Loew. 



Fore femora and sometimes the middle ones also, with long black hairs or 

 bristles below, if they have yellow hairs below, then the hairs, are 

 scarcely longer than those on upper surface 24 



24. Hind tarsi wholly yellow 25 



Hind tarsi wholly black_ 26. 



25. Posterior surface of fore femora with long black hair ; posterior edge of 



pleurae black as usual (District of Columbia; New Jersey; New York; 



Pennsylvania; Massachusetts) 28, minuta Loew. 



Fore femora with only short black hair; posterior edge of pleurae yellow 

 (Maryland; Indiana) 29, flavipes, new species. 



26. Hind tibiae wholly black, still sometimes yellowish brown at base (New 



York; Canada) IS, thoracica, new species. 



Hind tibiae yellow with a black tip 27 



27. Scutellum with a few small black hairs on its disk ; hind femora broadly 



black at tip (Virginia to Canada) 17, albicans Loew. 



Hind femora wholly yellow or very narrowly black or brown at tip ; scutel- 

 lum bare on its disk 28 



