THE DIPTEROUS GENUS DOLICHOPUS IN NORTH AMERICA. 161 



This differs from Imstatus Loew in having the lamella on the arista 

 longer; the hypopygium is much shorter and the lamellae are very 

 much smaller than in hastatus; the wing has nearly the same lobe at 

 the anal angle, but here the hind margin is nearly straight between 

 the tips of fifth and sixth veins, while in Jiastatus it is deeply sinuous 

 between these points. 



The two species resemble each other very much in the form and 

 color of the antennae and arista, the lobe at tip of sixth vein, the 

 color of middle tibiae and the glabrous spot on theh upper surface. 



This is another example of the remarkable grouping of two or more 

 species with several prominent and striking characters in common 

 and yet with good distinguishing points by which to separate them, 

 which we meet in this genus. 



Type.- — ^In California Academy of Sciences. 



No. 111. DOLICHOPUS DORSALIS, new species. 



Male.- — Length 5.7 mm.; of wing 5.5 mm. Face rather wide, nar- 

 rowed a little below, silvery white. Front green, with white pollen 

 along the orbits. First antennal joint yellow, second mostly yellow, 

 but blackened at tip; thhd wholly black, about as long as wide, 

 somewhat orbicular in outline, still a little pointed at tip. Lateral 

 and inferior orbital cilia yellowish white, about five of upper cilia 

 black. 



Thorax green, dorsum with a narrow median and wide lateral 

 coppery vittae, considerably dulled with thick yellowish gray pollen. 

 Abdomen green with coppery reflections; white pollen on its sides 

 abundant and extending over the dorsum. Hypopygium black; its 

 lamellae large, somewhat triangular in outline, but with the upper 

 corner rounded, whitish with a moderately wide black border on the 

 apical margin, which is jagged and bristly, more deeply so at lower 

 corner. . 



Fore coxae wholly yellow, their anterior surface covered with 

 white pollen and minute black hairs, which are mixed with delicate 

 yellow ones on outer half. Femora and tibiae yellow. Middle and 

 hind femora each with one preapical bristle, the latter bare below. 

 Posterior tibiae a little infuscated on inner side at tip; the usual 

 glabrous stripe on upper surface between the two rows of large 

 bristles distinct but somewhat broken by a few little hairs. Middle 

 tibiae with three bristles below, a pair at apical third and one at basal 

 third; they have three quite distinct glabrous spots on upper side. 

 Fore tarsi a little longer than their tibiae, yellow, a little infuscated 

 toward the tip, fifth joint almost black; first joint a little longer 

 than the following two taken together, second half as long as first, 

 third and fifth of about equal length, fourth a little shorter. Middle 



