400 THE NOETH AMERICAN EMPID^—COQUILLETT. vol. xvm. 



46. Veuter destitute of a bristly process in front of the hypopygium 47 



Venter furnished with two curved, bhxck, bristly processes in front of the 



hypopygium; filament of the latter hidden ; length, over 6 mm. .hevigata. 

 Venter with a single large process bristly at the posterior cud; thorax sub- 

 opaque gray pollinose, with three subshiuing black \ittx.. rirgaia (p. 408). 



47. Wings brownish; length, 3^ mm 48 



Wings hyaline 49 



48. Anterior branch of third vein straight and nearly perpendicular, fourth vein 



not reaching the wing margin. . lahiata. 



Anterior branch very oblique, filament of hypopygium very thick ohesa. 



49. Fourth vein reaches the wing margin; anterior branch of the third vein 



curved and very oblique, scutellum bearing four bristles; length, 5 to 

 6 mm sociabilis. 



Fourth vein reaches the wing margin, scutellum bearing six or more bristles; 



length, 6 to 8 mm ravida (p. 403). 



Fourth vein not reaching the wing margin ; anterior branch of third vein 



straight and nearly perpendicular; length, nearly 4 mm distans. 



50. Posterior femora not ciliate with scales 52 



Posterior femora ciliate with nearly erect scales 51 



51. Anterior tibia; ciliate with scales distaus. 



Anterior tibia) not ciliate lahiata. 



52. Abdomen shining or subshiniug 53 



Abdomen opaque, light gray pollinose, legs slender, base of femora and of 



tibia? yellow; length, 4 mm stenoptera. 



53. Abdomen depressed, very robust, hind femora furnished with stout black 



spines on the under side ; length, 6 to 7 mm 54 



Abdomen compressed, slender, hind femora destitute of spines on the under 



side ; legs slender ; length, 5 to 6 mm sociabilis. 



54. Thorax opaque, costa of wing bearing a long bristle near its base, contact 



of the fourth posterior cell with the discal equal to the contact of sec- 

 ond basal cell with the fourth posterior otiosa (p. 407)* 



Thorax wholly shining, costa of wings destitute of a long bristle, contact of 

 fourth posterior cell with the discal nearly twice as long as the con- 

 tact of the second basal cell with the fourth posterior lo'vigata. 



Thorax shining except four pollinose vittiB virgata (p. 408). 



55. Anterior branch of third vein terminates in the costa 56 



Anterior branch of third vein usually terminates in the second, this branch 



and the small and posterior cross veins bordered with brown, all 

 femora and tibi;e of female ciliate with nearly erect scales. c?aitsa (p. 401). 



56. Legs of female not ciliate with scales 57 



Legs of female ciliate with nearly erect scales; scutellum bearing only two 



bristles ; length, 3 to 4 mm distans. 



57. Wings colorless; length, 4 mm corimis. 



Wings brownish ; scutellum bearing about twenty bristles, length 5 mm. . hictuosa. 



EMPIS LORIPEDIS, new species. 



Male. — Head black, gray pollinose ; eyes separated as widely as the 

 posterior ocelli, facets of a uniform size; antenuse black, third joint 

 somewhat over twice as long as the first, slender, tapering gradually to 

 the middle, thence of an equal breadth ; style nearly one-third as long as 

 the third joint; i)roboscis one and one-half times as long as height of 

 head, palpi yellow. Thorax black, opaque gray pollinose, marked with 



