SYNOPSIS OF NORTH AMERICAN SYRPHID^. 151 



COPESTYLUM.* 



Copeslylnm Macquart, Dipt. Exot. le Sii])])!., ViA, 1846. 



Wholly like some species of Volucella (e. g., V.fasciata, V. satur, etc.), 

 -except in the structure of the nnteniine. Body short; abdomen short, 

 broad, oval, fasciate : legs rather slender. Face produced directly down- 

 wards, obtusely conical below, pointed and notched at the tip, slightly 

 tuberculate below the middle; front arched; antennae situated near 

 upper third of head in TJrofile, slender, first joint very short, second 

 joint a little elongate, third joint slender; arista inserted near tlie base, 

 longer than the joint, thickened throughout its length, densely plumose 

 with short, flattened, hair-like pile, appearing under a low-power glass 

 like a solid mass, under a higher power (20-30 diameters) the arista 

 shows a gradual thickening to near its end; tlie pile is fine near its in- 

 sertion, but flattened beyond, in structure not unlike elongated scales 

 from some lepidoptera. Eyes pilose, contiguous in male. Wings as in 

 Volucella, marginal cell closed and petiolate, tip of fourth vein bent in- 

 ward, small cross vein near middle of discal cell, oblique. Type of 

 genus C. marginatum (Say) O. S., Xorth America. 



Copestylum marginatum. (Plate VII, 1iy;s. 1, la, Ih.) 



roluecUa vian/inata Say, Jour. Acad. Phil., vi, 167,3; Conipl. Wr., ii, 360; 



Ostou Sacken, West. Dipt., 333. 

 Copest)ihtm_flavircntris Maeqnart, Dipt. Exol. le Sapj)!., 12.'); pi. x, lig. 16. 

 Copestylum mari/iiiaii(m Otsten Saekeu, Cat. Dipt., 130. 



EahitaL—Maxico (Say), Venezuela (Macq.), Texas, Arizona, Mon- 

 tana, California! 



5.9. Length, to 11*"'". Face whitish yellow, with a black median 

 stripe, reaching from, or near, the base of the antennne to the oral mar- 

 gin ; cheeks black, shining, with a narrow yellow stripe running from 

 the eye to the oral margin, sometimes the yellow predominates, leaving 

 only a black stripe; antennne varying from alight yellowish -red to quite 

 black, second joint about one-third the length of the third joint. Frontal 

 triangle black, shining, or with two oblong yellow spots near the orbit 

 (var. lentum, name new), pile usually light-colored, sometimes black; 

 front in female black on the upper half, on the sides below the yellow 

 of the face sometimes extends up, partly cut off by an expansion from 

 the black at the base of the antennie; near the middle of the front are 

 two small, oval spots, that are sonietimes wanting, at other times con- 

 fluent with the yellow of the sides. Thorax black, shining, with whitish 

 pile, which is longer on the pleurae; sides of dorsum with a stripe, en- 

 tire or interrupted, and two spots in front of the scutellum, yellowish. 

 In other specimens the pile is longer, mixed with black, or wholly black, 

 and the yellow of the dorsum is entirely wanting (var. lentum). Scutel- 

 lum yellow, with white, blackish, or black pile. Abdomen black, with 

 *Ko7r//, a .strikiug, and dTvXoi, a style. 



