256 ERNEST A. BACK. 



"Face yellow above, silvery below; mystax, pile of front, of antenna? 

 and the beard white. Antennas black, rather acute at tip. Dorsum 

 of thorax densely covered with whitish-yellow bloom, the pile of nearly 

 the same color; pleura? polished black, with small patches of yellowish- 

 white bloom. Abdomen slender, wholly polished. Legs black, the 

 front femora on the under side, the tip of middle femora and more or 

 less along the under side, the hind femora at tip, the four anterior 

 tibia? except the immediate tip and the hind tibia? on rather more than 

 the basal half, light reddish-yellow; hind femora much thickened, 

 more so comparatively than in albius. Wings on the basal half light 

 yellow, from the cross- veins on blackish." 



Type. — University of Kansas. Three male specimens. 



Habitat. — Washington (type); Mt. Hood, Ore.; White Mts., 

 N. H. (Osten Sacken and Geo. Dimmock) ; North Mt., Pa. 

 (June 9, C. W. Johnson). 



There are specimens of this species in the collections of the 

 M. C. Z., Univ. of Ks. ; National Museum, and that of Prof. C. 

 W. Johnson. See note under albius. 



Dioctria vera n. sp. 



$. — Length about 7 mm. — Very slender polished black species with 

 very slender hind femora and unusually large metatarsi for an American 

 species of this genus; all the femora black above, reddish-yellow below; 

 wing darkish hyaline. 



Polished black; face brassy-yellow, front polished, occiput thinly 

 golden pruinose, the bloom being more dense along the orbits. Bris- 

 tles of mystax few, fine, confined to oral margin golden; pile of basal 

 segments of antenna?, frontal orbits, occiput and beard paler yellow. 

 Antenna? black; first two segments slender, cylindrical, first segment 

 noticeably longer than the second; third segment linear, much more 

 slender than in albius, densely pubescent, somewhat as in Cereturgus 

 cruciatus, only the protuberance does not appear except under a strong 

 lens; style nearly equaling in width the third segment and a trifle less 

 than one-quarter its length, rather obtuse, densely pubescent. Thor- 

 acic dorsum with a rather thin golden pubescence which leaves a 

 median geminate strip bare; bristles along the sides very few, short, 

 golden; pleura? polished black; the pubescence light golden, arranged 

 as follows, — a proportionately broad band extending over the anterior 

 portion of the meso- and sternopleura? and reaching to the front coxa?, 

 a narrow line extending from base of wing along the mesopleural groove, 

 and, then widening, turning back beneath the pteropleron, a very small 

 patch just above and behind the middle coxa? and a longer patch 

 between the halteres and coxa?. Trichostical pile short, golden, as also 

 is that upon the posterior margin of the scutellum. Halteres yel- 



