THE DIPTEROUS GENUS DOLICHOPUS IN NORTH AMERICA. 101 



Calypters pale yellow with black cilia, which are decidedly yellow 

 in certain lights; halteres yellow. 



Wings (fig. 57) very slightly tinged with brown in front; veins 

 dark-brown, yellow at the root of the wings; costa black, not enlarged 

 at tip of first vein; last section of fourth vein only a little bent near 

 basal fourth, from which point the third and fourth veins approach 

 each other and are nearly straight, their tips rather close together; 

 hind margin of wing slightly indented at tip of fifth vein; anal angle 

 rounded, still rather prominent. 



Female. — Face wider than that of the male, third antennal joint 

 about as long as wide; trochanters brown or black; middle femora 

 black with yellow tip; hind femora with one preapical bristle; fore 

 and middle tarsi wholly yellow; hind tibiae blackened at tip for 

 about one-third their length. Wings as in the male, except that 

 the bend in fourth vein is beyond basal third and the tips of third 

 and fourth veins are a little farther apart. 



It may prove that this is a different species from the male described 

 above, as it has but one preapical bristle and the middle tarsi are 

 yellow. vStiil the wing venation would indicate that they belong 

 together. 



Described from one male and one female taken in Polk County, 

 Wisconsin, by C, F. Baker in July. 



Type.— Male, Cat. No. 23006, U.S.N.M. 



No. 58. DOLICHOPUS LATICORNIS Loew! 



Dolichopus laticornis Loew, Neue Beitr., vol. 8, 1861, p. 12; Mon. N. Amer. 

 Diptera, pt. 2, 1864, p. 29. — Aldrich, Kansas Univ. Quart., vol. 2, 1893, 

 p. 7. — Melander and Brues, Biol. Bull., vol. 1, 1900, p. 148. 



Male. — Length, 4.2-5 mm. ; of wing, 3.5-4 mm. Face rather wide, 

 scarcely narrowed below, silvery white, sometimes a little yellowish 

 just below the antennae. Front green or blue green. Antennae 

 (fig. 58a) wholly black; third joint large, more than twice as long as 

 wide, pointed at tip; arista inserted near apical third, about as long 

 as the antennae. Orbital cilia wholly black. 



Thorax green, sometimes with coppery reflections which form 

 indistinct vittae on the dorsum; pleurae dulled with gray pollen. 

 Abdomen dark green, sometimes with coppery reflections, its sutures 

 narrowly black; the white pollen on its sides forms large spots on 

 the lower edges of the segments. Hypogyium black; its lamellae 

 of moderate size, somewhat triangular in outline, rather acutely 

 pointed at tip, white with a very narrow dark border which is more 

 distinct near the apex, not jagged on apical margin, fringed with 

 small dark hairs. 



Coxae black with yellow tips and white pollen; anterior pair with 

 minute white hairs on the front surface. Fore and hind femora 



