THE DIPTEROUS GENUS DOLICHOPUS IN NOETH AMERICA. 251 

 f 



No. 184. DOLICHOPUS TONSUS Loew. 



Dolichopus tonsus Lowe, Neue Beitr., vol. 8, 1861, p. 16; Mon. N. Amer. Dipt., 

 pt. 2, 1864, p. 47. — Aldrich, Cat. N. Amer. Dipt., 1905, p. 301. — Melander 

 and Brues, Biol. Bull., vol. 1, 1900, p. 148.^ — Johnson, Insectsof New Jersey, 

 1909, p. 756. 



J/aZe.— Length 6 mm. ; of wing the same. Face rather narrow, pale 

 golden yellow, more whitish on the lower part. Front green, some- 

 what shining. Antennae wholly black; third joint about as long 

 as wide, pointed at tip. Lateral and inferior cilia yellowish, about 

 seven of the upper cilia on each side black. 



Thorax green; dorsum with white pollen along the front and central 

 portions, which always leaves a median, shining vitta which is often 

 coppery and sometimes with copper spots on the sides; pleurae 

 dulled with white pollen. Abdomen green with coppery reflections; 

 the white pollen on its sides abundant and extending upon the dorsum. 

 Hypopygium black: its lamellae large, somewhat elliptical, but taper- 

 ing into the stem, whitish with broad black border on apical margin; 

 jagged and bristly at lower corner, above this fringed with pale hairs 

 to about middle of upper edge; from that to the base the hairs are 

 black. 



Fore coxae 3'ellow, clothed on anterior surface with minute yellow 

 and black hairs; sometimes they are mostly yellow and at others 

 mostly black. Middle and hind coxae black with yellow tips, femora 

 and tibiae yellow. Middle and hind femora each with one preapical 

 bristle, the latter without cilia below, but with a row of little yellow 

 hairs on lower inner edge, which are not longer than tne hairs on upper 

 edge. Middle tibiae with three bristles below, one pair at apical third 

 and one bristle at basal third, their basi tarsi with a large bristle above; 

 posterior tibiae scarcely thickened; the glabrous stripe on upper sur- 

 face poorly defined. Fore tarsi (fig. 184a) about one and two-thirds 

 times as long as their tibiae; second joint two- thirds as long as first; 

 third, fourth, and fifth of nearly equal length and each a little shorter 

 than the second; fourth and fifth joints much conpressed; fourth 

 white, silvery on the sides, nearly half as wide as long; fifth joint 

 black, a little wider than the fourth, with a silky luster on the sides. 

 Middle tarsi about one and one-fourth times as long as their tibia^, 

 infuscated from the tip of the first joint, still only the tips of the 

 joints black. ' Hind tarsi black from the base of the second joint, but 

 sometimes colored about like the middle ones. Calypters, their cilia, 

 and the hal teres yellow. 



Wings (fig. 184) grayish; costa not enlarged at tip of first vein; last 

 section of fourth vein bent near its basal third; hind margin of wing 

 slightly flattened between the apex and tip of fifth vein, scarcely 

 indented at tip of fifth vein; anal angle a little prominent, but the 

 wing narrowing from tip of sixth vein to the anal angle. 



