Juneiyoo.l CaSEY : On NoRTH AMERICAN CoLEOPTERA. 155 



to be very rare in individuals, and it is seldom that more than a single 

 one it taken at any one time ; most of the species, which appear how- 

 ever to be abundantly distinct among themselves, are therefore repre- 

 sented at present by unique types. Peri- ^.^^^ ^ 

 megatoma resembles it in this respect to 

 some extent. The pale coloration of advena 

 may be due to immaturity, at least partially. 

 In the adjoining diagram the antenna of 

 adveiia, which is representative of that en- ^ ^ _ 

 tire section of the genus, is drawn in a con- \ ^^^J^^ ^^ Trogodcr.ua tar- 

 tracted state, but the insect has the power ,„/,-^ ^ ^ ^ same r. scrriger-, 3 

 to separate the joints slightly, when they are same of t. oMonguia, 4 same of 

 seen to be deeply concave at their apices ; 



they are mutually'attached by short stipes or pedicels as in the others, 

 but differ in being virtually symmetrical and not eccentric. These 

 antennal differences, although marked, are not indicative of subgen- 

 eric groups, as the general structure of the under surface, and partic- 

 ularly of the hypomera, is indentical throughout. 



Cryptorhopalum Gucr. 



The body in this genus, which is the most extensive of the Ameri- 

 can Dermestidie, becomes more oval and compact than in any other 

 of the present tribe, but in anatomical structure it is evidently homol- 

 ogous with Trogodcnna. The species are small to quite minute in 

 size, of sober color and generally uniformly clothed with short dark 

 pubescence, which, in some forms, becomes slightly variegated as in 

 most of the other genera. The species before me are the following : — 



Pubescence of the elytra variegated 



Pubescence uniform throughout 



2— Elytra with in-egular or interrupted transverse bands of dense paler pubescence... 3 



Elytra without transversely fasciate pubescence, but with a spot of dense pale and 

 coarser hairs near the apex of each ; last ventral of the female unmodified 8 



3 -Last ventral segment of the female with two small, widely separated and rounded 

 discal erosions; elytra not paler posteriorly 4 



Last ventral of female with two small, rounded, flat and entirely unexcavated scar- 

 like spots ; elytra paler in apical third 7 



4_Pubescence of the pronotum dusky, sparse and inconspicuous but becoming pale 

 and conspicuous toward the sides and on the basal lobe ■■•5 



Pubescence of the pronotum uniform or nearly so, coarse, denser, pale and conspicu- 

 ous throughout 



