TENEBRIONID^E 191 



cabinet, which prevents me from confirming the very exceptional 

 length of the antennae ascribed to it by its author. Of cochisensis 

 there is before me a very good series of seven males and three fe- 

 males and two notable facts regarding it become thereby apparent, 

 the first being the very great variation in the posterior extension of 

 the reflexed elytral margin in the males and the equally striking 

 constancy in the length of this sharply upturned margin in the 

 female, and the second being the evident and very constant dis- 

 parity in the size of the sexes. There is very little variability 

 otherwise as far as noted. 



Adhering to one of the examples of cochisensis is a very regularly 

 elongate-oboval pale yellowish mite, of convex form and highly 

 polished even surface; it is proportionally of very large size, being 

 about 0.78 mm. in length. A specimen of Phellopsis porcata, in 

 my collection, bears a number of pale mites which are of a totally 

 different form, being narrowly oblong and parallel, very flat, with 

 the legs longer and protruding for some distance at the sides, the 

 body crossed at the middle by a very fine suture differentiating the 

 abdomen, the small head partially visible; its size is much smaller, 

 being scarcely 0.28 mm. in length. From what I have very casually 

 seen of these mites infesting beetles, they are remarkably diversified 

 and would form a life-long study in themselves. 



Group II Type polita Say. 



In spite of the very different habitus of this group, due to the 

 stout oblong convex body and transverse prothorax nearly as wide 

 as the elytra, there are no structural characters of moment affecting 

 special organs to distinguish it from the preceding group, excepting 

 the basal angles of the prothorax, which however isolate it con- 

 spicuously in the genus; these angles are always obtuse and more 

 or less blunt. The species are mutually so similar that it may be 

 said of all of them that the prothorax is much narrower at apex 

 than at base, the apex circularly and rather deeply sinuate, the 

 base broadly, feebly arcuate, becoming transverse and very feebly 

 sinuate laterally, the hind angles not quite so posterior as the median 

 arcuate part of the base. The elytra are always evenly convex 

 at the sides, becoming acutely carinate and reflexed uniformly in 

 basal fifth to sixth; the elytral base is broadly, feebly sinuate, 



