THE DIPTEROUS GENUS DOLICHOPUS IN NORTH AMERICA. 103 



Coxae black with yellow tips and thin silvery pollen, anterior pair 

 with a few minute white hairs on the front surface. Fore and hind 

 femora black with tips and extreme base yellow. Middle femora and 

 their trochanters yellow. Middle and hind femora each with one 

 preapical bristle. Fore and middle tibiae and tarsi wholly yellow, 

 the latter scarcely darker at tip. Fore tarsi scarcely as long as their 

 tibiae, fourth joint shorter than fifth. Middle tarsi about one and a 

 fourth times as long as their tibiae, the tibiae being longer than their 

 femora. Hind tibiae mostly black, upper edge yellowish at base for 

 about one-fourth their length and shading into the black, the glabrous 

 stripe on upper surface rather wide, extending inside of the inner row 

 of large bristles for a short distance near basal third; their hairs long 

 and dense, especially on apical two-thirds. Hind tarsi shining black, 

 with stiff black hairs. Calypters, their cilia, and the halteres pale 

 yellow. 



Wings (fig. 59) grayish; costa with a very distinct enlargement at 

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

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

 converge, still their tips are not very close together; hind margin of 

 wing a little notched at tip of fifth vein, back of this notch it widens 

 a little; anal angle rather prominent. 



Female. — Face wide, grayish white; all femora black with extreme 

 base and tips yellow; fore tibiae and tarsi yellow; middle tibiae and 

 tarsi black with the articulations yellowish; hind tibiae and tarsi 

 wholly black; notch at tip of fifth vein not as conspicuous as in the 

 male; costa without an enlargement at tip of first vein; wings tinged 

 with brownish in front and along the veins; cilia of the calypters more 

 or less black. 



Described from 3 males and .3 females. Two males and 1 female 

 were taken at Montreal, Quebec, June 3 and 23; 1 pair were taken 

 by me at East Aurora, New York, June 2; and 1 female at Ridgeway, 

 Ontario, July 15. 



Tvyo^.— Male, Cat. No. 23007, U.S.N.M., from East Aurora, New 

 York. 



This differs from the male of laticornis Loew in having the hind 

 tibiae much darker, clothed with much longer hair, and its glabrous 

 stripe narrower; the middle femora wholly yellow, not black at base; 

 costal enlargement at tip of first vein more conspicuous; third and 

 fourth veins distinctly convergent at their tips. The females differ 

 in having the middle tibiae black with extreme tips yellow, and the 

 hind tibiae wholly black; the third and fourth veins convergent as 

 in the male, while in laticornis they are parallel at tip. 



