266 ERNEST A. BACK. 



third segment but little longer than the two preceding taken together. 

 The usual thoracic stripes are dark brown, the white or yellowish 

 bloom in their intervals forms the following pattern: a median line, 

 attenuated posteriorly; a figure in the shape of a tuning-fork, having 

 the end of the handle in front of the scutellum, connected with the 

 end of the median line; a broad stripe on each side between the 

 humeral and the posterior callosities, attenuated and abbreviated 

 before reaching the latter; these lateral stripes are twice connected 

 by pruinose cross-bands with the branches of the tuning-fork, the 

 second time, along the transverse suture. Scutellum black, with 

 black pile; grayish pruinose anteriorly. Pleurae grayish pruinose, 

 with a stripe of more dense silvery-gray bloom on the lower part; the 

 trichostical hairs black. Abdomen black, polished, with a bluish reflec- 

 tion on the first five segments; each of these, and often the sixth, has 

 a large white pruinose spot on each posterior lateral margin; the sides 

 of the abdomen are clothed with white hairs, which become gradually 

 shorter posteriorly and do not reach beyond the fifth segment; hypo- 

 pygium black, with black pile. Legs black; bristles on the tibiee black; 

 femora with long white hairs on the under side; the hind pair also on 

 the upper side near the base. Halteres reddish-yellow. Wings hyaline 

 on their proximal half, including the discal cell; the distal half has a 

 slight grayish tinge; cross- veins clouded with brown. 



Type. — M. C. Z. Two female co-types. 



Habitat. — Catskill Mountain House (type; July), N. Y.; 

 White Mts. and Mt. Washington (C. W. Johnson), N. H. 



The above description is Osten Sacken's, altered somewhat 

 so as to include the male, of which I have seen a single spec- 

 imen, belonging to Prof. C. W. Johnson. "The altogether 

 black legs; the strong contrast between the brown thoracic 

 stripes and the whitish pruinose intervals between them; the 

 altogether black beard, etc., will help to distinguish this 

 species." — Osten Sacken. 



A female specimen from Mt. Ranier, Wash., in the collection 

 of the University of Kansas is very close to lyriatus and alleni, 

 more so to the former, but differs in that the pile of the face 

 is white in the middle; the hind tibiae are reddish at base; the 

 pleurae more densely pruinose above; the thoracic dorsum is 

 black with a distinct figure in the grayish bloom which re- 

 sembles Osten Sacken's tuning-fork, but the handle is very 

 broad where it touches the scutellum, and there is, between 

 the two prongs, a short line of bloom that extends in between 

 the black geminate stripe. 



