126 PROCEEDINGS ENTOMOLOGICAL SOCIETY 



Antennas yellow, except at tip of the third antennal joint; front 

 in the female as wide or slightly wider than either eye; one 

 or two pairs of frontal bristles descending below the base of 

 antennae; sides of face each one-fifth as wide as the median 

 depression; the facial ridges bristly on the lowest half; 

 the third antennal joint five times as long as the second; 

 arista thickened at least on the basal two-fifths; penulti- 

 mate joint usually longer than broad; thorax dusted 

 yellowish-gray pollinose; wings subhyaline, slightly smoky 

 tinged costally; apical cell open, the third vein bearing 

 two or three bristles at its base. Length, 6 to 9 mm. Four 

 females from Opelousas, Louisiana, May, 1897, and Ger- 

 mantown, Pennsylvania. Type, 4063, U. S. National 

 Museum. (Can. Ent., vol. XXX, p. 234.) tarsalis Coq. 



9. Legs black; bristly hairs or macrochaetse on the sides of the 



face arranged in a single row 10 



Legs yellow; bristly hairs or macrochaetse on the sides of the 

 face not arranged in a single row; the tip of proboscis, the 

 sides of the first two abdominal segments, and usually 

 the apex of the abdomen yellow; front in the male one-third 

 to one-half as wide as, in the female as wide as either eye; 

 parafrontals, parafacials, and the cheeks yellowish-gray 

 pollinose; three or four pairs of frontal bristles descending 

 below the base of the antenna?; facial ridges bristly on 

 the lowest third; third antennal joint in both sexes 

 two to two and one-half times as long as the second ; arista 

 thickened on the basal two-fifths, the penultimate joint 

 as broad as long; thorax gray pollinose; scutellum bearing 

 three pairs of long marginal and a short apical pair of 

 macrochaetse; middle tibia? each bearing a single macro- 

 chaeta on the front side near the middle; abdomen gray- 

 ish pollinose; moderately carinate on the venter; bearing 

 both discal and marginal macrochaetse; wings hyaline; 

 apical cell open; the third vein bearing two bristles at its 

 base. Length, 8 to 10 mm. 3 males and 1 female from 

 Washington, D. C. (List Dipt. Insects, part IV, p. 779, 

 1849, Tachind) .- demylus Walk. 



10. Middle tibiae each bearing a single macrochaeta on the front 



side near the middle; front in the male as wide as, in the 

 female one and one-fifth times as wide as either eye; cheeks 

 one-third as broad as the eye height; sides of face each 

 one-fifth as wide as the median depression; facial ridges 

 bristly on the lowest fourth; parafrontals and parafacials 



grayish-white pollinose; the third antennal joint four 

 times as long as the second; arista thickened on the basal 



third, penultimate joint as broad as long; thorax gray 



