THE DIPTEROUS GENUS DOLICHOPUS IN NORTH AMERICA. 163 



base, especially below. Hind tarsi black; first joint rather slender for 

 a DolicTiopus and with two large bristles on upper surface. Calypters 

 and halteres yellow, the former with black cilia. 



Wings grayish, more yellowish brown in front of third vein; costa 

 not enlarged at tip of first vein ; last section of fourth vein a little bent 

 before its middle; hind margin of wing scarcely indented at tip of 

 fifth vein, rather evenly rounded, the anal angle not being very 

 much developed. 



Described from 1 male which I took on Grand Island, Erie County, 

 New York, August 17, 1913. 



Type.—Male, Cat. No. 23030, U.S.N.M. 



No. 113. DOLICHOPUS MARGINATUS Aldrich. 



DoKchopus marginatus Aldrich, Kansas Univ. Quart., vol. 2, 1893, p. 17. — 

 Melander and Brues, Biol. Bull., vol. 1, 1900, pp. 135 and 148. 



Male. — Length 5.5-6 mm.; of wing 4.2-5 mm. Face rather wide, 

 white, sometimes more grayish. Front violet with a narrow green 

 edge above the antennae and along the orbits. First and second 

 antennal joints yellow, usually with the upper edge very narrowly 

 black; third joint black with the base or even half yellow, somewhat 

 conical in outline, but little longer than wide, obtusely pointed at 

 tip. Lateral and inferior orbital cilia pale yellow; about seven of 

 the upper cilia on each side black. 



Thorax shining green with bronze reflections, which often form a 

 median vitta on the dorsum; pleurae dulled with white pollen. 

 Abdomen green with coppery reflections on the hind margins of the 

 segments. Hypopygium black; its lamellae (fig. 113) rather large, 

 somewhat orbicular in outline, white with a rather wide, sharply 

 defined black border on apical margin, jagged and bristly at lower 

 apical corner, otherwise fringed on apical and upper margins with very 

 long curved black hairs. 



Fore coxae yellow with a blackish spot at base on outer side, ante- 

 rior surface with black hairs except at upper outer corner, where the 

 hairs are yellow. Middle and hind coxae yellow on inner side and at 

 tip, black on outer surface for two-thirds their length. Femora and 

 tibae yellow. Middle and hind femora each with one large preapical 

 bristle, the latter ciHated on lower inner edge with long black hairs, 

 the longest of which are longer than the width of the femora. Pos- 

 terior tibiae sUghtly thickened, infuscated at tip on inner side for 

 one-fourth their length and with a brown line on inner surface from 

 near their base to the middle, sometimes almost uniting with the 

 blackish color at tip, the glabrous stripe on upper surface broad 

 and conspicuous, a little broken before the tip by a few little hairs. 

 Fore and middle tarsi a little longer than their tibiae, darkened 

 toward their tips. Fore tarsi with the last^two joints black; first 



