4 PROCEEDINGS OF THE NATIONAL MUSEUM vol. G6 



28. Fore coxae distinctly blacliened at base and with conspicuoiis blaciv hairs 



(Maine; Mass;uiuisetts ; Canada) 22, sericata, new species. 



Fore coxae wholly yellow, almost bare except for the bristles near the tip 

 (Quebec) 24, albicoxa, new species. 



29. Hind basitarsus wholly black (California) 9, argentiventris, new species. 



Hind basitarsus mostly yellow 30 



30. Hind tarsus with its joints as 32-13-13-10-9, first joint mucli thickened and 



with numerous bristles (Virginia to Canada 25, calcitrans Leow. 



Joints of hind tarsi as 50-20-18-11-8, their first joint scarcely thickened 

 and with a few bristles on each edge, of lower surface (Vermont; New 

 York; New Jersey; Ontario) 26, setipes, new species. 



31. Antennae yellow, third joint very narrowly black on upper edge (Kansas; 



Louisiana) 30, flavicornis, new species. 



Antennae black or brown 32 



32. Hind basitarsi with numerous bristles ( Virginia to Canada ) , 



25, calcitrans Loew. 



Hind basitarsi with only the usual short hair 33 



83. Hind basitarsi wholly black or nearly so 34 



Hind tarsi wholly yellow, or slightly darkened at tip 39 



34. Hypopygium large, contracted in the middle (fig. 19), its lamellae long and 



curved (New Jersey; Connecticut; Rhode Island) 27, aldrichi Johnson. 



Hypopygium not large or contracted, normal 35 



35. Posterior edge of pleurae and first abdominal segment yellow 36 



Posterior edge of pleurae and first abdominal segment blackish 37 



36. Second and third abdominal segments with a longitudinal black or green 



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



Second and third abdominal segments wholly yellow, except the narrow 

 hind margins (New York; Canada) 24, albicoxa, new species. 



37. Fore coxae wholly pale yellow with silvery pollen ; middle femora with only 



short hairs below (Ontario; Quebec) 19, currani, new species. 



Fore coxae blackened at base, or wholly black ; middle femora with long 

 black or brown bristles below 38 



38. Fore coxae wholly black (Ohio) 20, nigricoxa, new species. 



Fore coxae yellow, blackened at base (Maine; Massachusetts; Canada), 



22, sericata, new species. 



39. Arista inserted before apical third of third antennal joint (Marylaml; 



Indiana) 29, flavipes, new species. 



Arista inserted close to the tip of third antennal joint as usual (East- 

 ern States) . 28, minuta Loew. 



Females 



1. Abdomen without yellow on the dorsum, at most with indistinct lateral 



spots on second segment 2 



Abdomen with distinct yellow ground color on some of the segments 15 



2. Scutellum with hairs on its disk 3 



Scutellum bare, except the marginal bristles 6 



3. All femora wholly yellow, except sometimes at tip 4 



Fore and middle femoi-a more or less blackened at base 5 



4. Hind femora wholly yellow 7, scutellaris, new species. 



Hind femora broadly black at tip 14, bimaculata, new species, 



5. Cilia of the calypters yellowish 12, robusta Johnson. 



Cilia of the calypters black 15, velutina, new species. 



G. Fore and middle femora black on basal half or more- 13, ciliata Van Duzee. 

 All femora yellow, the tips of posterior pair may be black 7 



