278 ERNEST A. BACK. 



like that of dasylloides. It is hardly safe, having seen so 

 little material, to express the opinion that these two species 

 may eventually be proved the same, yet such is my conviction. 



Cyrtopogon dasylloides. 



Cyrtopogon dasylloides Williston, Trans. Am. Ent. Soc, XI, 11, 

 1884. 



"%. — Length 17 mm. — Black, thickly black pilose; mystax thick, 

 light yellow; coxae with white pile. Abdomen, except the tip, with 

 long, dense, furry, erect, light yellow pile; tarsi red; wings hyaline, 

 the distal half in front blackish. 



"Face very thickly light yellow pilose, on the lowest portion some- 

 what black; beard white. Style of antenna; short, thickened. Pile 

 of the front, occiput and of the first two segments of antenna; black. 

 Thorax thickly black pilose, dorsum nearly opaque, on the sides of 

 the middle in front a little brownish pruinose; bristles not strong. 

 Scutellum thickly pilose, not pollinose, convex. Abdomen nearly 

 parallel on the sides, polished, but its shape and color nearly concealed 

 by the very long, erect, furry, yellow pile, the first segment with a 

 very little black pile above on the sides, and the last segments and the 

 hypopygium wholly thickly pilose. Coxa; white pilose. Legs black, 

 densely black pilose, hind tibiss deep red, all the tarsi lighter red, the 

 front pair with white pile. Wings hyaline, the outer half in front from 

 the margin of the third vein blackish, a little lighter at the tip, and 

 fading out behind." 



Type. — University of Kansas. One male specimen. 

 Habitat. — Washington. 



The pile of the abdomen is evenly distributed and not at 

 all arranged in tufts. 



Cyrtopogon longimanus. 



Cyrtopogon longimanus Loew, Berl. Ent. Zeit., 1874, 360. 



Cyrtopogon longimanus Osten Sacken, West, Dipt., 303, 1877. 

 % . — Length 8-9 mm. — Translation by Osten Sacken from Loew. 

 The ground color of the whole body is, without exception, polished 

 black. The front with long black pubescence with which are mixed 

 some whitish hairs, or such which appear whitish toward the tip. 

 Antenna; black; the first two segments sparsely beset with black hairs, 

 partly whitish toward their tips ; the third segment very slender, 

 strongly coarctate in the middle; terminal style slender, a little more 

 than half as long as the segment. The long mystax reaches up to the 

 antennae, and is composed in the middle of hairs which are whitish or 

 black at their base only; the hairs on its outer side, all around, are 

 exclusively black, so that, seen from the sides, the mystax seems to 



