588 



FAMILY XXIV. DERMESTIDA. 



partly covered with pale gray or brown spots composed of minute 

 scales or hairs which are easily rubbed off. When disturbed they 

 usually "play possum," folding back their legs and rolling over on 

 their backs, where they remain quiescent for some time. The name 

 of the typical genus, Dermestes, is derived from two Greek words 

 meaning "a skin" and "to devour," whence the common name of 

 skin-eaters or skin beetles. 



The principal distinguishing characters of the family are the 

 small deflexed head; eyes rounded, with small facets, the front 

 usually with a third simple eye or ocellus; antenna? short, inserted 

 in front of eyes, usually 11-. sometimes 9- or 10- jointed, the last 

 two or three joints forming a large club ; thorax short, in the ma- 

 jority of species excavated beneath for the reception of the an- 

 tenna?; elytra covering the abdomen, not striate; abdomen with five 

 free ventral segments; front coxa? rather long, conical or oblique, 

 the cavities open behind except in Byturus; middle coxa? oval, 

 oblique; hind coxa? slightly separated, usually dilated into a plate 

 partly protecting the femora and formed to receive the latter in 

 repose ; legs short, tibia? with distinct spurs ; tarsi 5-jointed, claws 

 usually simple. 



The larvae of the majority of Dermestids are brown, active grubs 

 clothed with long hairs and usually with a brush of similar hairs at 

 the end of the body. Many of them have a peculiar gait, running 

 for a short distance, then stopping and vibrating the hairs with 

 great rapidity. They are much more destructive than the adult 

 beetles, but at times appear to be able to live for long periods with 

 little or no food. 



Between 300 and 400 species of Dermestida? are known, about 85 

 of which, with numerous varieties^ are from North America. The 

 principal literature treating of these is as follows: 



LeConte. — "Synopsis of the Dermestida 1 of the United States, " 

 in Proc. Phil. Acad. Nat. Sci., VIII, 1854, 106-113. 



Jayne. — " Revision of the Dermestida? of. the United States," in 

 Proc. Amer. Phil. Soc, XX, 1882, 343-377. 



Casey. — " Review of the American Dermestida?," in Journ. N. 

 Y. Ent. Soc, VIII, 1900, 138-165. 



The members of the family which have a range including Indi- 

 ana are distributed among eight genera. 



KEY TO INDIANA GENERA OF DERMESTIDyE. 



a. Tarsi with second and third joints lobed beneath ; front coxa! cavities 

 closed behind; claws armed with a large basal tooth. (Fig. 221.) 



I. Byturus, 



