OSTEN SACKEN ON WESTERN DIPTERA. 247 



3fale. — Frontal triangle black, with short, erect, black pile ; face with 

 a dense covering of short snow-white pile ; antennae black ; occiput 

 black, with appressed white hairs along the orbits; thorax grayish - 

 black, with a dense covering of delicate, downy, whitish-gray pile, which 

 iu an oblique light looks altogether white ; the few bristles on the ante- 

 scutellar callosities and on the scutellum are whitish, almost colorless; 

 abdomen black, with the same covering of grayish-white pile, which is 

 longer here on the sides. Halteres whitish ; knob brownish. Legs black, 

 densely clothed with white scales ; spines on femora and tibite whitish- 

 yellow. Wings, including the costal cell, of a pure hyaline ; veins, ex- 

 cept at the root, black; costal and first longitudinal brown. 



Female. — Like the male, but the front is slightly brownish pruinose, 

 and has, besides the erect, black pile, some short, recumbent, yellowish 

 hairs. The hind margins of the abdominal segments are beset with 

 some short, appressed, whitish hairs, forming cross-bands. 



Hah. — I have a single male, which I took near the Salt Lake, Utah, 

 August 1. One of the females is from Sonoma County, California, July 

 6; the other from the Shasta district (H. Edwards, July, 1875). 



Oncodocera. 



Oncodocera leucoprocta Wiedemann, i, 330 (Mulio); male (syn. 

 Oncodocera dimicUata Macq., D. E., ii, 1, 84, female). — Middle and 

 Southern States ; Illinois ; Wisconsin. 



Leptochilus modestus Loew, Centur., x, 40. — Texas. ) I do not know 

 Aphcebantus cervinus Loew, Centur., x, 39. — Texas. | these species 



BOMBYLIUS. 



The species from the Atlantic States may be grouped as follows : — 



1. Anterior half of the wings brown, with a well-defined, sinuous, pos- 



terior limit of that color : 

 fratellus Wied., i, 583. 



Syn. — vicinns Macq., ii, 1, 93. 



aWipectus Macq., 5e suppL, 82. 



ccqualis Harris (nee Fabr.), 3d edit., 604. 



major Kirby, Fauna Bor.-Am., 312. 



2. Wings brown at base, and with brown spots on the posterior half: 



jndchellus Loew, Centur., iv, 47. 

 pygiiucus Fab., Wied., i, 351. 



3. The brown of the basal half of the wings is gradually evanescent 



posteriorly : 



airiceps Loew, Centur., iv, 49. 



mexicanus Wied., i, 338. 



Syn. — /((Zn&rtsis Macq., 5e siippl. (Synonymy on the antliority of Mr. 



l}hiladelphicus Macq., ii, 1, 99. ^ Loew, in litt. 



varius Fab., Wied., i, 335. 

 ralidus Loew, Centur., iv, 48. 



