256 Journal New York Entomological Society. [Voi. xxl 



Mesonotum polished ; last section of the fifth vein shorter than the pre- 

 ceding section; front black; four dorsocentrals. (Mex.) 



picfa Coquillett. 



43. Sides of front yellow along the orbits; knees broadly yellow; hairs of 



calypteres black ; fourth vein ending at wing-tip, wings broad. (Eur.;* 



Wash.,* Ore.*) superciliosa Zetterstedt. 



Frontal orbits black ; knees narrowly yellow ; hairs of calypteres pale ; 

 fourth vein ending usually beyond the wing-tip (compare also luctuosa 

 in couplet 31) 44. 



44. Apical segments of J' abdomen yellow ; wings broad, the third and fourth 



veins somewhat divergent, the fourth vein ending much beyond the 

 wing-tip ; frontal lunule marked with a small white dot ; arista long 

 and pubescent. (N. H., Pa., Fla., La.,* 111.,* S. Dak.*) 



terminalis Coquillett. 



Abdomen black, the incisures more or less yellow ; the third and fourth 



veins subparallel, the fourth vein ending at or slightly beyond the 



wing-tip 45. 



45. Arista more than two times the length of the antenna, plainly pubescent, 



the antennse short ; wings broad ; frontal lunule white-pollinose. 



(Mass.,* N. J., Pa., La., 111.,* Wise, Wash.*) angulata Loew. 



Arista shorter, bare ; wings narrow 46. 



46. Antennae large, porrect, the arista thick ; sections of the fifth vein sub- 



equal ; scutellum black 47. 



Antenna small, the arista slender; discal cell small, the sections of the 

 fifth vein 1:2; scutellum yellow. (Wash.*) interfrontalis n. sp. 



47. Antennae strikingly large ; thorax pollinose ; four dorsocentrals ; frontal 



kmule often yellow, {viagnicornis Loew.) (Eur.;* Mass., N. J., 

 Pa., Ga., III.,* Wise.,* S. Dak., Col., Wash.*) . .grossicornis Zetterstedt. 

 Antennae not abnormal ; thorax subshining ; four or three dorsocentrals ; 

 frontal lunule black. (Proc. Ent. Soc. Wash., VI, 191, 1904-) (Cal.,* 

 Ore.,* Wash.,* Alaska.*) tccniola Coquillett. 



48. Antennae black, at least the third joint black 49- 



Antennae entirely yellow, sometimes the end of the antenna may become 



infuscated above 54- 



49. Front entirely yellow, or centrally yellow ; fringe and margin of the calyp- 



teres dusky 5 o- 



Center of front above lunule velvet black, bordered with yellow on the 

 sides ; wings narrow, the penultimate section of the fourth vein one 

 third as long as the ultimate section and longer than the posterior 

 crossvein, the sections of the fifth vein subequal ; calypteres and fringe 

 white ; pollinose species. (Mass., D. C, Ind.,* 111.*) . .marginata Loew. 



50. Plump shining black species, with black antennae and legs ; front narrower 



than long; two or three dorsocentrals. {platyptera Thomson.) ... .^'i. 

 Notum pruinose ; front square ; four dorsocentrals 53. 



51. Frontal orbits black, at least above; subantennal grooves more or less 



