106 COLEOPTERA OP NORTH AMERICA. 



Maxilla? with the base exposed, with two lobes of variable 

 form ; palpi small, slender, 4-jointed. 



Antennae inserted in front of the eyes, usually 11-jointed, 

 variable in Anthrenus, 9-jointed in Dearthrus, and 10-jointed 

 in certain foreign genera, with the last three joints forming 

 a large club. 



Head small, deflexed; epistoma very short, coriaceous; 

 labrum distinct; mandibles short; eyes rounded, front usu- 

 ally with a single ocellus or simple lens. 



Prothorax short, with the side pieces not separate, some- 

 times excavated beneath for the reception of the antennas ; 

 coxal cavities large, transverse, closed behind by the meso- 

 sternum, except in Byturus; prosternum prolonged behind, 

 except in Dermestes and Byturus, and usually lobed in front. 



Mesosternum prominent, rounded or subacute in front in 

 Dermestes, emarginate in the others; side pieces attaining 

 the coxae. 



Metasternum short, truncate in front; side pieces wide. 



Elytra covering the abdomen, not striate; epipleurse obso- 

 lete behind. 



Abdomen with five free ventral segments. 



Anterior coxae conical, prominent, with small trochantin; 

 middle coxae oval, oblique, excavated externally, with large 

 trochantin, usually distant ; posterior slightly separated, 

 transverse, not extending to the margin of the body (except 

 in Orphilus), dilated into a plate partly protecting the thighs, 

 which is, however, almost obsolete in Byturus. 



Legs short, somewhat contractile; tibise with distinct spurs; 

 tarsi 5-jointed, joints 1 — 4 short, usually equal, fifth longer; 

 claws simple in the second sub-family, toothed in Byturidas. 



This family comprises small oval insects, some of which are 

 found on dried animal remains, others only on plants. Several of 

 them are very destructive to furs and objects of natural history. 



The genera indicate two sub-families : — 



Tarsi with second and third joints lobed beneath. Btturid^e. 



Tarsi simple. Dekmestid^. 



Sub-Family I.— BYTTTRIDAE. 



This sub-family consists of a single genus, Byturus, represented 

 by one species from the Atlantic district and one from the Pacific. 

 It departs remarkably from the next sub-family by the mandibles 

 having several teeth, by the tarsi having the second and third 



