232 BULLETIN 63, UNITED STATES NATIONAL MUSEUM. 



Sternite quadrato-parabolic and slightly transverse. Lobes slightly 

 elongate, each with the external border feebly sinuate in basal half, 

 thence evenly and rather broadly arcuate to aj^ex, the latter rounded ; 

 internal border membrano-chitinous and not well defined in basal 

 half; surface more or less convex, from the middle gradually sloping 

 to the sinus, rather coarsely punctate and setose; setae rather long at 

 apex and moderately dense; membrane not setose across the bottom 

 of the sinus ; the latter broad, 



Fetnale. — Genital segment somewhat equilaterally triangular, 

 slightly flattened, and setose. 



Valimla (Plate 4, fig. 23).^ — Dorsal plate oblong oval; sides more or 

 less reflexed; surface more or less concave, smooth, and shining; 

 finely and sparsely punctate, each puncture with a fine and rather 

 short seta ; external margin more or less feebly arcuate; apical margin 

 feebh" arcuate, angle scarcely evident; internal margin more or less 

 arcuate, feebly sinuate in basal half; apex short, triangular, subacute 

 at tip, and finely setose. Valvular membrane visible in apical half. 



Appendage about as long as the apex, conical, with a loose tuft of 

 fine and not very long hairs at tip. 



Superior pudendal meynhrane finely and not closely longitudinally 

 rugulose, not quite attaining the middle of the dorsal plate. 



Ventrolateral surfaces. — Body evenly but not strongly convex, and 

 not transversely concave before the apex, shining and glabrous, 

 finely, sparsely punctate and setose; submarginal groove obsolete; 

 internal margins of the valves contiguous in basal fifth. Genital 

 fissure long, fusiform, and rather wide, closed by the inferior puden- 

 dal membrane in basal half, apically by the valvular membranes. 



Habitat. — Nevada (Humboldt Valley, Mr. Krause), California 

 (Amedee, Lassen Count}^, July, elevation 4,200 feet., H. F. Wickham). 



Number of specimens studied, IG. 



Type in the Horn collection. 



Type-locality. — Humboldt Valley, Nevada ; collector, Mr. Krause. 



Salient type -characters. — Clothed with long, black, flying hairs. 

 Thorax about a fourth wider than long; sides arcuate in front. 

 obliqueW narroAved posteriorly; disc moderately convex, coarsely, 

 sparsely, irregularly punctate; apex slightly emarginate, anterior 

 angles subacute, but not everted. Elytra with disc feebly convex, 

 very vaguely sulcate; surface irregularly, sparsely muricate, the two 

 grooves nearest the suture coarsely punctate. Elytra prolonged at 

 tip in a cauda. (Male.) (Horn.) 



Diagnostic characters. — Remarkably distinct among its congeners 

 on account of being clothed throughout with long black or brownish 

 flying hairs; caudate in both sexes with the anterior femora obso- 

 letely dentate. 



