414 THE NOB TR AMERICAN EMPID^—COQ UILLETT. vol. sviii. 



52. Inhabits California; both sides of hind femora and tibife, under side of mid- 



dle femora and outer side of middle tibia? of female, ciliate Avith nearly 

 erect scales ; length, 3 mm hictuosa. 



Inhabits Nebraska; all femora and tibite of female ciliate with scales., hvvigata. 



Inhabits Illinois; eyes of male contiguous, filament of hypopygium free, 

 slender, not flexuous, pile in front of halteres black, scutellum bear- 

 ing four bristles polita. 



Inhabits the Atlantic States; legs of female not ciliate with scales; eyes of 



male contiguous; filament of hypopygium hidden angustipennls. 



53. Middle and hind femora and hind tibiie of female ciliate with nearly erect 



scales; eyes of male contiguous; filament of hypopygium slender, not 

 flexuous ; inhabits the Atlantic States irevis. 



Middle and hind tibijB of male bearing black seta^, filament of hypopygium 



hidden, eyes of male contiguous; inhabits the Atlantic States., pectinata. 



Middle and other legs of females destitute of nearly erect scales ; eyes of male 

 contiguous; filament of liyi^opygium very thick, hidden except at 

 base; inhabits the Atlantic States umbrosa.. 



Middle and other femora and tibia' not ciliate with scales; inhabits Califor- 

 nia hifilaia (p. 424:). 



54. Thorax wholly shining, not pollinose; knob of halteres yellowish; discal 



cell and veins issuing from it normal ; eyes of male contiguous 55 



Thorax more or less opaque 58 



55. Filament of male hypopygium hidden, except sometimes on its basal third.. 56 

 Filament free, slender, not flexuous, upper facets of eyes of male much larger 



than the lower; his hind metatarsi much thicker than the others; 

 both sides of middle and hind femora and hind tibii^ of female, also 

 outer side of her middle tibi;p, ciliate with nearly erect scales; wings 

 grayish, stigma black ; length, 2 mm nana. 



56. Abdomen shining; length, 3 to 4i mm 57 



Abdomen opaque, wings whitish, stigma obsolete, third antennal joint short 



and broad, style minute ; length, 2 mm 2^"*'0- 



57. Scutellum bearing four bristles, pile in front of halteres black, outer side of 



middle tibije of male bearing numerous bristles ininijtus. 



Scutellum bearing only two bristles, pile in front of halteres whitish, outer 

 side of middle tibiii^ of male bearing only two bristles, both sides of 

 hind femora and under side of middle femora of female ciliate with 

 nearly ei'ect scales cHiata. 



58. Knob of halteres yellowish 59 



Knob of halteres blackish 92 



•59. Discal cell normal " 62 



Discal cell united with the first and second posterior cells, legs of female des- 

 titute of nearly erect scales ; pile of body whitish, third antennal joint 



broad, bases of first two tarsal joints white incompJeta. 



Discal cell prolonged nearly to the wing margin, legs of female not ciliate 



with scales ; length, 3 to 4 mm \ 60 



60. Two veins issue from the discal cell 61 



Three veins issue from the discal cell, the cross vein at its apex angular, scutel- 

 lum bearing two bristles in-egularis. 



61. Wings grayish, vein at apex of discal cell sinuous, never angular limhata. 



Wings hyaline at base, the apex dark gray, vein at apex of discal cell angular 



near its lower end; inhabits California ampliceUa (p. 431). 



62. Fourth vein reaches the wing margin 67 



Fourth vein obliterated before reaching the wing margin, legs of female 



destitute of erect scales; length, 2 to 3 mm 63 



63. Males 64 



Females 65 



