42 BULLETIN 31, L'XITED STATES NATIONAL MUSEUM. 



scare, on tbe sides longer, whitish. Legs yellow ; hind femora, except 

 basal third and tip, a ring on the outer part of hind tibiae, and the hind 

 tarsi, brown or blackish; sometimes the black is of greater extent on 

 the hind legs, and there may be brownish rings on the outer part of 

 middle femora and tibiae. Wings hyaline. 



$ , Face wholly shining black, except the thin whitish pollen below 

 the antennae and on the sides below the tubercle. Frontal triangle 

 small, slightly swollen, lightly fossulate, pile black. Thorax and scu- 

 tellum wholly shining black, with only a slight bronze or coppery re- 

 flection; pile black, rather long, esjiecially in front; behind, intermixed 

 with reddish yellow. Scutellum wholly shining black, pile loug, black, 

 with reddish yellow, the latter more conspicuous as a fringe on the un- 

 der side of the margin. Abdomen opaque black ; the first segment, large 

 spots on the anterior angles of the third, the fourth segment wholly, and 

 likewise the hypopygium, shining, metallic greenish black ; pile on 

 the disk black ; on the sides toward the front, longer, yellow. Legs 

 black, tip of all the femora, base and tip of the tibiae, and the extreme 

 base and tip of all the tarsal joints, yellowish red. Wings distinctly 

 yellowish or brownish in front toward the base. 



Five males and forty females taken together (Jackson, N. H., July 

 25-30,) assure me that they must belong together. The females agree 

 precisely with the description of pallqjes, except that they are all larger, 

 while the males agree equally well with tristis, the female of which 

 Loew describes ; and the only differences which it shows from the above 

 are that the legs are black, except the knees and base of the tibiae, and 

 the light-colored humeri are not mentioned. In some of my female 

 specimens, however, the front and middle legs are in large part black- 

 ish, and in one they are almost wholly black. Two male specimens from 

 Washington Territory and Oregon 1 refer to this, although the pile of 

 the dorsum of the thorax is wholly black, and the legs are less black, 

 the front and middle tibiae having only a black ring, and the first two 

 joints of the tarsi yellowish. They are also distinctly larger. 



Chilosia cyanescens. (Plate III, figs. 3,4.) 



Chiloda cyanescens Loew, Ceutur., iv, 67 (male). 

 ? Chilosia plumata Loew, ibid., 68 (female). 



Habitat. — Connecticut, New Hampshire!, Illinois (Loew). 



<J. Length, 5 to 6™°^; of wings, 6 to 7™"'. Blackish blue, shining; pile 

 of the front and thorax black, of the abdomen light colored. Antennae 

 small, yellowish red, third joint ovate; arista black, plumose. Face 

 wholly black ; except on the moderately projecting tubercle, lightly pol- 

 linose. Eyes bare. Frontal triangle small. Margin of the scutellum 

 with black bristles; on the under side with whitish pile. Abdomen 

 wholly shining. Femora black, at the tip reddish yellow ; anterior and 

 middle tibiae reddish yellow, with a black ring ; hind tibia* black, the 

 base somewhat broadly, the tip narrowly, reddish yellow ; the first two 

 pairs of tarsi yellow, their last joint black, hind tarsi black, the third 



