THE DIPTEROUS GENUS DOLICHOPUS IN NORTH AMERICA. 67 

 No. 28. DOLICHOPUS AGRONOMUS Melander and Brues. 



Dolichopus agronomus Melander and Brues, Biol. Bull., vol. 1, 1900, pp. 140 

 and 148.— Aldrich, Cat. N. Amer. Diptera, 1905, p. 299. 



Male. — Length 3.5-4 mm.; of wing 3-3.75 mm. Face rather 

 wide and perhaps rather long (Melander and Brues in their description 

 say it is very long, I should not call it unusually so, but it appears 

 longer on account of the lower portion below the usual transverse 

 ridge being very short). Front silvery white, still the green ground 

 color shows through in certain lights. Antennae wholly l^lack (fig. 

 28a); third joint large, nearly twice as long as wide, pointed at tip; 

 arista only a little longer than the antenna, inserted a short distance 

 before the point. Cilia of the lateral and inferior orbits white, a few 

 of the upper cilia black. 



Thorax green with slight bronze reflections; dorsum covered with 

 thin white pollen, which leaves a median shining vitta, this vitta in 

 some specimens is slightly coppery with a fine green line on each 

 side; pleurae more blackish with grayish pollen. Abdomen green 

 with coppery reflections along the center of the dorsum and narrowly 

 black at the incisures, covered with white pollen which is more con- 

 spicuous on the lower part of the sides. Hypopygium black; its 

 lamellae rather small, oval, jagged at apex where there are the 

 usual bristles. 



Coxae black with yellow tips and white pollen, that on the anterior 

 surface of fore pair silvery; the hairs on anterior coxae yellowish. 

 Femora black, their tips and the trochanters yellow; middle and 

 hind femora each with one preapical bristle, the latter with very 

 delicate whitish cilia on lower inner edge, the longest of these hairs 

 about half as long as width of femora (sometimes the cilia are shorter 

 and so delicate as to be easily overlooked). Fore and middle tibiae 

 yellow; posterior pair black, slightly thickened, the usual glabrous 

 stripe on upper surface narrow but extending their whole length. 

 Fore tarsi yellow, infuscated toward their tips (in the type specimen 

 black from the tip of the first joint), a little longer than their tibiae, 

 which are also short. Middle tarsi about one and a half times as 

 long as their tibiae, yellow at base, becoming blackish at tip. Hind 

 tarsi black. Calypters, their cilia and the halteres yellow (I do not 

 see the strong black hair among these cilia mentioned by Melander 

 and Brues in their description). 



Wings a little grayish (fig. 28) ; costa not or scarcely enlarged at tip 

 of first vein; last section of fourth vein bent before its middle, nearly 

 parallel with third beyond this bend, still the third vein bent back a 

 little at tip; hind margin of wing scarcely indented at tip of fifth 

 vein; anal angle nearly obsolete, the wing being much narrowed at 

 base; root of wing yellow, veins blackish. 



