June 1900.] Casey: On North American Coleoptera. 139 



the claws unmodified, the sternal side pieces very wide and the hind 

 coxas lamellate and transversely excavated. The antennas are ex- 

 tremely varied in structure and may or may not be received within 

 protecting pits or excavations, and the legs may be free or strongly 

 retractile. In considering the depression for the protection of the 

 antennas, a distinction should be drawn between a large and vaguely 

 limited concavity of the hypomera — or inflexed side of the prothorax — 

 as in Dermestes, and a closely circumscribed and sharply defined pit ; 

 the former characterizes most of the genera in some form, and be- 

 comes a true protective fossa in a few genera, but the latter only oc- 

 curs in Anthrenus. 



The genus Trixagus {Bytunts Lat.), is evidently allied to the 

 Dermestidas, but differs in so many radical characters, such as the 

 closed anterior acetabula, lobed tarsi, dentate claws, narrow sternal 

 side pieces and structure of the mesosternum, that the position as- 

 signed it by Reitter as a distinct family is probably as satisfactory as 

 any, and I have therefore not considered it in the following revision. 

 As thus restricted, the American Dermestidas may be assigned to five 

 distinct tribes characterized as follows : — 



Head without ocellus ; anterior coxae large, contiguous, the prosternum not visible 

 between them, the mesosternum between the coxae moderately wide, ogival and 

 not sulcate; antennas 11 -jointed, with a 3-jointed club, similar in the sexes and 

 not received within sharply circumscribed pits ; hypomera concave anteriorly ; 

 epipleurae strongly defined, wide and inflexed toward base ; body clothed with 

 short hairs DERMESTINI 



Head with a single ocellus 2 



2 — Prosternum visible between the coxae; metacoxal lamina not extending totheside s 

 cf the body 3 



Prosternum not visible between the coxa; ; metacoxal lamina extending to the sides of 

 the body 5 



3— Metacoxal plate extending laterally half way across the parapleural ; prosternal 

 process impinging upon the exposed surface of the mesosternum between the 

 coxa; ; epipleurae well developed toward base ; legs in great part free ; body 

 clothed with short hairs Attagenini 



Metacoxal plate only extending laterally to and abutting against — squarely in Trino- 

 dini, obliquely in Anthrenini — the inner boundary of the parapleural 4 



4 — Epipleurae subobsolete ; lateral margin of the prothorax entire as usual ; antennal 

 club received within deep fossae at the apical thoracic angles ; body compact, 

 clothed with decumbent scales, the legs all very closely retractile ; coxae large ; 

 scutellum very minute Anth renin i 



Epipleurae narrow but strongly delimited and inflexed toward base ; lateral thoracic 

 margins obliterated at apex ; legs and antennae perfectly free, excepting, as usual, 



