AMERICAN DIPTERA. 183 



Ablautus trifarius. 



Ablautus trifarius Loew, Cent., VII, 63, 18G6. 



Ablautus trifarius Osten Sacken, Biologia, Dipt., I, 168, 1887.* 

 9 • — Length 6-7 mm. — Grayish pruinose, on the dorsum more brown- 

 ish; abdomen with three rows of black spots; legs wholly brownish 

 yellow. 



Grayish pruinose, head of the same color; bristles of the basal seg- 

 ments of the antennae, vertex, occiput, and thoracic dorsum, scutellum, 

 sides of first abdominal segments and of the legs, wholly yellowish. 

 Face densely clothed with white pile reaching to the antennae, black 

 only on the oral margin; beard white, dense, and extending well 

 upwards; the basal segment of the black antennas with rather short 

 black pile. Dorsum with the characteristic pile and bristles, the stripes 

 nearly obsolete, dark, the geminate stripe divided by a grayish line 

 and much abbreviated behind, the lateral stripes hardly noticeable, 

 interrupted. Scutellum densely clothed with a grayish bloom which, 

 when viewed from behind or in certain lights, appears shining white, 

 its margin armed with the closely set yellowish bristles mentioned 

 above. Abdomen black, grayish pruinose, opaque, each segment be- 

 ginning with the second with a median and two lateral rather small 

 black spots on the anterior margin, one median, and one on each side; 

 the eighth segment is wholly black; pile short, white, backward 

 directed, chiefly on the sides of the segments. Legs brownish, tibiae 

 and tarsi much lighter; closely covered with long recumbent white 

 hair and long erect yellowish bristles; on the tarsi the bristles are 

 part black. Claws wholly black. Wings pure hyaline, veins black. 



Type. — M. C. Z. A single female in rather poor condition. 

 Habitat. — California (type). 



OSPRIOCERUS. 



Ospriocerus Loew, Cent., VII, 51, 1866. 



Ospriocerus Schiner, Verh. Zool.-Bot. Ges., 1866, 846; quotes 



orig. desc. 

 Ospriocerus Coquillett, Ent. News, IX, 37, 1898; synopsis of 



species. 

 Ospriocerus Williston, Biologia, Dipt., I, 303, 1901; notes. 



Large elongate black species, with or without red on the 

 abdomen. Head narrower than the thorax, almost as high 

 as broad, with the vertex but slightly depressed. Antennae 

 elongate, the first segment not less than three times the length 

 of the small cup-shaped second, the third, more than the 



* A specimen from N. Sonora, Mex., which he doubtfully refers to 

 this species. 



