52 BULLETIN 116, UNITED STATES NATIONAL MUSEUM. 



York, Aug. 8; Toronto, Ontario, July 3 (Van Duzee); Montreal, 

 Quebec, Aug. 6. 



Type locality. — Saratoga, New York. Aldrich reports it from 

 Minnesota and South Dakota; Melander and Brues from Illinois. 



Type. — In Museum of Comparative Zoology, Cambridge, Massa- 

 chusetts; has been examined. 



No. 15. DOLICHOPUS ENIGMA Melander and Brues. 



Dolichopus enigma Melander and Brues, Biol. Bull., vol. 1, 1900, p. 139, fig. 



Male. — Length 4-5.2 mm.; of wing the same. Face rather broad 

 but short, silvery white, appearing dark gray in most lights. Front 

 shining green. Antennae (fig. 156) wholly black; third joint a little 

 longer than wide, somewhat conical in outline, scarcely pointed at tip. 

 Lower orbital cilia white; the black cilia descending about one- third 

 of the eye height. 



Thorax shining green, sometimes with bronze reflections; pleurae 

 a little dulled with gray pollen. Abdomen green with very slight 

 bronze reflections. Hypopygium black; its lamellae (fig. 15a) 

 moderately large, quadrangular in outline but the stem placed close 

 to the lower corner, yellowish white with a black border, which is 

 widest on apical margin, jagged and bristly at apex, its sides fringed 

 with little hairs. 



Coxae, legs, and feet black, the knees scarcely yellowish. Fore 

 coxae with white pollen and minute black hairs on their anterior 

 surface. Middle and hind femora each with one preapical bristle, the 

 latter ciliate with pale hairs on lower inner edge of apical half, which 

 are nearly as long as the width of femora (easily overlooked); hind 

 tibiae only slightly thicker than the others, the glabrous stripe on 

 upper edge can be seen as a shining line between the rows of large 

 bristles. Fore and middle tarsi a little longer than their tibiae. 

 Third and fifth joints of fore tarsi of nearly equal length, fourth a 

 little shorter. Middle tibiae with one bristle below, their basitarsi 

 without a bristle. Hind tarsi one and a fourth times as long as their 

 tibiae. Calypters and halteres yellow, the former with black cilia, 

 which appears more or less pale in certain lights, in the type specimen 

 it is almost white. 



Wings (fig. 15) grayish, a little darker in front; costa with a very 

 small knot-like enlargement at tip of first vein; last section of fourth 

 vein bent just beyond its basal third; hind margin of wing scarcely 

 indented at tip of fifth vein; anal angle rounded, only a little 

 prominent. * 



Redescribed from the 1 male type in the American Museum at 

 New York, taken at North Park, Colorado, .at 9,000 feet elevation in 

 July; and 4 males taken by J. M. Aldrich, at Marshall Pass, Colorado, 

 July 28, at 10,856 feet elevation. 



