146 NORTH AMERICAN 



spine, liaving at the middle of its length one or two interior and two exterior 

 stout oblique spines ; anterior tarsi strongly dilated ; corresponding coxae 

 strongly globose, dark brown in color, surface coarsely imbricate. Length 

 (contracted) 2.8 mm. 



District of Columbia, 1. 



It may be possible that tliere is a second smaller spine at the apex 

 of the middle tibiae, but it is not visible in the type specimen. It 

 appears to belong immediately after bisignatus. The structure and 

 shape of the pronotum and elytra in many species of the present 

 genus call to mind very vividly several forms of Tricliopteryx on a 



C. corticola n. sp. — Form rather slender. Color piceous-black ; elytral 

 humeri scarcely distinguishably reddish ; abdomen not paler except at- tip 

 and by transmitted light ; pubescence rather dense, short and coarse, very 

 pale yellowish, more dense and conspicuous on the abdomen. Head much 

 wider than long, rather convex, highly polished, very minutely punctate, 

 punctures being nearly com])letely filled by the hairs ; sides of the contigu- 

 ous emargination of the pronotum nearly parallel at the apical angles viewed 

 longitudinally ; antennae robust, scarcely as long as the head and prothorax 

 together, first two joints translucent, dark tlaVo-testaceous, eleventh opaque, 

 pale tiavate, remainder piceous-black, basal joint rather robust, narrowed 

 toward base, scarcely more than twice as long as wide, second but very 

 slightly shorter and thinner, oval, third as long as the first, slightly thinner 

 than the second, narrowed toward base, four to ten decreasing very gradually 

 in length and increasing in width, the former about three-fourths as long as 

 the third, scarcely two-thirds longer than wide, the latter one-fourth wider 

 than long, sides of all very feebly convergent toward the base, nearly straight, 

 basal angles feebly rounded, eleventh very abruptly pale, scarcely one-third 

 longer than wide, oval, very feebly constricted at tip which is obliquely and 

 obtusely rounded, outer joints rather strongly compressed, basal joints with 

 two long setae above near the tips, outer joints coarsely setose and finely 

 pubescent. Prothorax widest at one-fourth the length from the base where 

 it is nearly two-thirds wider than long; sides moderately arcuate; apex 

 broadly and feebly arcuate, sinuate near the apical angles, fully tiiree-fifths 

 as long as the base which is broadly and feebly arcuate ; basal angles from 

 above obtuse and not rounded, viewed laterally obtuse, very slightly pro- 

 duced and very slightly rounded, sides almost straight toward the apical 

 angles which are right and not at all rounded ; disk very strongly convex, 

 polished, minutely evenly and rather distantly punctato-asperate, inter- 

 spaces very minutely and feebly strigato-reticulate. Elytra at base slightly 

 narrower than the pronotum ; sides feebly convergent posteriorly, rather 

 distinctly arcuate near the humeri, straight toward the apical angles which 

 are rounded ; together nearly transversely truncate behind ; inner apical 

 angles slightly rounded ; disk very strongly convex, shining, slightly wider 

 than long and distinctly longer than the pronotum ; sculpture strongly 

 rather finely and somewhat distinctly imbricate, imbrications as wide as 



