NORTH AMERICAN COLEOPTERA. 45 



coxte conical, oblique, contiguous, the cavities narrowly separated. 

 Legs slender, moderately long. Tarsi slender, the last joint longer 

 on the front and middle feet, first joint longer on the hind feet. 



The head and thorax in form are not unlike that of Crymodes, the 

 elytra are, however, narrowed toward the apex, being quite excep- 

 tional in the family. The general organization is that of the true 

 Pythidse as defined by Lacordaire. The autennse are, however, very 

 remarkable, and are not unlike those of many genera of Anobiini. 

 The first eight joints are smooth with a few hairs, the last three 

 opaque, the surface very finely punctured and ap{)arently sensitive. 



T. River!>iii n. sp. — Moderately elongate, dark castaueous, elytra yellowish 

 testaceous, surface shining. Head brown, densely coarsely punctured posteriorly, 

 more sparsely iu front, a slight concavity at middle of clypeus. Thorax casta- 

 neous, shining, sparsely punctate, disc slightly flattened, a vague oblique depres- 

 sion each side of middle, the two converging posteriorly. Elytra yellowish tes- 

 taceous or luteous, very shining, punctures rather sparse and indistinct at base, 

 more distinct near apex, margin with short cilise. Body beneath piceous, nearly 

 smooth. Abdomen darker. Legs brown. Length .47 inch ; 12 mm. PI. iii, tig. 26. 



The specimen before me is a male. The last ventral segment is 

 broadly, but rather deeply trumgularly emarginate, the last dorsal 

 slightly emarginate. It is po.ssible that the form of the antenna? mav 

 be merely sexual, or at least the female antenna? may not have the 

 last three joints so elongate. 



One specimen from Arizona kindly given me by Mr. J. J. Rivers, 

 of the University of California. 



PYTHO Latr. 



The species of this genus, although few in number, .seem to be 

 misunderstood, more from the fact that the descriptions are scattered 

 than from any real trouble in se})arating them. The following notes 

 will assist in the determination : 



Base of thorax constricted, forming a collar; median line of thorax broad and 



deep Strictiis. 



Ba.se of thorax not constricted, the sides arcuate from the front to hind angles ; 

 median line of thorax tine. 

 Color, when mature, black, shining ; legs black, surface without metallic lustre ; 



prosternum in front and gula not punctate nigger. 



Color piceous or castaneous ; legs and undereide reddish-yellow, surface blue 

 or violet, even when partly immature ; prosternum more or less punctate, 

 gula transversely wrinkled ^iniericiiiius. 



P. strictii!^ Lee, New Species, 1866. p. 168. 



All the specimens seen are brownish with paler elytra, the surface 

 without metallic lustre. 



