AMERICAN COLEOPTERA. 115 



and basal margins are yellowish-testaceous, the remaining portion 

 brownish, but with lines indicating the striae paler. Occasionally the 

 pygidium is not prominent, in this case the sub-truncation of the ely- 

 tra is rendered still more evident. 



Occurs from Montana westward to Oregon. 



Section II contains the bulk of our species, usually of moderate or 

 small size, several of them however large, rivaling those of the preced- 

 ing group in length, although never very robust, but few of them are 

 notably convex, many depressed. Many curious sexual characters have 

 been noticed, and will be adverted to in their proper places. The 

 scutellum is small, triangular, never longer than one-eighth or one- 

 tenth of the elytra. 



As the species are numerous, they may, for convenience, be divided, 

 in accordance with the suggestions of Erichsou, into groups. 



Apex of hind tibiae fringed with short equal spiuules. 

 Thorax distinctly margined at base. 

 Head more or less tuberculate. 

 Mesosternum not carinate. 



Clypcus sub-quadridentate Group C. 



Clypeus sub-emarginate. 



Sides of thorax, near hind angles, distinctly sinuate Group D. 



Sides of thorax rounded, not sinuate behind Group E. 



Mesosternum distinctly but slightly carinate Group F. 



Head not tuberculate; clypeus emarginate and bidenticulate Group G. 



Thorax not margined at base; head tuberculate; sides of scutelluni 



emarginate Group H. 



Apex of hind tibice fringed with unequal sijinules. 

 Head distinctly tuberculate. 

 Elytra yellow, with black spots ; base of thorax margined ; hind 



tibije stout Group I. 



Head not tuberculate. 

 Thorax not sinuate at sides near base. 



Elytra strigose: opaque black ; base of thorax margined ; hind 



tibiae slender Group K. 



Elytra glabrous, shining; tase of thorax more or less mar- 

 gined Group L. 



Elytra pubescent, sub-opaque Group M. 



Thorax distinctly sinuate on-the sides near hind angles. 



Clypeus denticulate; elytra oblong Group N. 



Clypeus emarginate; elytra oval Group 0. 



In using the above table the student must, at all times, be careful 

 that the specimens are perfect, that is, that the spinnles at the tips of 

 the tibia) are not worn or accidentally reduced to an equal size, or that 

 the long hairs fringing the sides of the tibiic do not, by crossing the 



