370 BULLETIN 63, UNITED STATES NATIONAL MUSEUM. 



Apicals triangular, a little longer than wide; surface moderately 

 convex, without groove; sides strongly and broadly sinuate, apex 

 appearing attenuate; base obtusely lobed at middle, feebly and 

 broadly sinuate laterally. 



Sternite transverse; each lobe triangular; surface feebly convex, 

 not very densely punctate, setose; setae moderate in length, gradually 

 longer about apex ; external border rather evenly arcuate and oblique, 

 apex introrsely placed and obtuse; internal border more or less sinu- 

 ate and oblique. Membrane not setose across the bottom of the sinus, 

 the latter triangular. 



Female. — Genital segment somewhat depressed, about equilaterally 

 triangular, dorsal surface feebly ogival, feebly setose. 



Valvula. — Dorsal plate oblong, three times longer than wide, sides 

 just the least converging apically; surface more or less feebly con- 

 cave, glabrous, veiy sparsely and finely punctured, setae short; ex- 

 ternal border feebly arcuate; internal border more or less sinuous; 

 apical margin more or less arcuately rounded and only apparently 

 defined from the semi-chitinous apex; the latter small, short and 

 scarcely more prominent posteriorly than the appendage, blunt and 

 more or less rounded, sparsely and finely setose with longer hairs, tip 

 Avith a pencil of moderately long hairs. Fossa large, in the external 

 surface of the apex. 



Appendage short triangulo-conical, with a pencil of long hairs at 



Superior pudendal memhrane longitudinally rugulose, t^.ttaining 

 the apical fourth of the dorsal plate. 



Basal prominences not evident. 



Ventrolateral surfaces plane centrally to base, surface lines straight 

 when viewed longitudinally, laterally rounded ; surface glabrous, with 

 a few coarse punctures scattered about, continuous with the semi- 

 chitinous apex, not at all concave before the apex, the latter finely 

 setose. Submarginal groove feeble at base, but well developed in 

 apical two-thirds beneath th6 feebly dilated external edge of the 

 dorsal plate. Internal margins of the valves contiguous in basal 

 two-thirds; fissure narrow and in apical third, about closed, and the 

 inferior membrane is not visible. 



ILdntaf. — California (Eldorado County, on the Avay to the summit 

 above Riverton, July). 



Number of specimens studied, 3. 



Sexitypes in my own collection. 



Type-locality. — Western slope of the Sierra Nevada Mountains, 

 above Riverton, Eldorado County, California. 



Salient type-diaracters. — See general description. 



Dkignostic characters. — This species differs from parmcolUs and 

 its races in the more oval and somewhat depressed form, finer and 



