AMERICAN COLEOPTERA. 337 



Closely allied to some of the paler forms of B. aureolus, but with 

 entirely black legs. The pubescence is also less dense and finer, and 

 the form more robust. In the table it appears closely allied to B. cal- 

 vus, but the latter has scarcely any pubescence and the surface much 

 more shining and the form more attenuate iu front. The pubescence 

 of B. calvus is not as might be inferred, lost by abrasion but very 

 sparsely scattered over the entire surface and regularly disposed. 



Specimens are abundant from the plains of Kansas, Nebraska and 

 Colorado. 



B. amicus, n. sp. — Oblong, black, moderately shining, densely clotbed 

 with silken white pubescence. Head oval, sparsely punctured, eyes scarcely 

 more prominent than the adjacent surface. Antennae as long as head and tho- 

 rax, feebly sub-serrate, black, four basal joints pale rufous. Thorax one-half 

 broader at base than long, sides moderately arcuate and gradually convergent 

 to apex, basal lobe broadly rounded, disc moderately convex, a small shallow 

 depression in front of basal lobe; surface comparatively smooth, moderately 

 shining, very sparsely punctulate, intervals densely and and very minutely 

 punctulate, surface color almost entirely concealed by silken white pubescence. 

 Scutellum small, broader than long, with white pubescence. Elytra conjointly 

 at middle as broad as long, at base slightly broader than the thorax, sides 

 moderately arcuate; disc flattened, striate, strise punctured, intervals flat, 

 punctulate, and with coarser punctures at base, clothed with silken white pu- 

 bescence. Pygidium oblong oval, feebly convex, sparsely punctured and 

 pubescent. Body beneath black, abdomen dark rufous, sparsely punctulate 

 and pubescent. Femora rufous, at base piceous, tibiae and tarsi piceous. 

 Length .20 — .22 inch; 5 — 5.5 mm. 



One of our largest species, having the form of B. prosopis and B. 

 uniformis. In mature specimens the color is dark piceous, frequently 

 however, specimens occur in which the thorax is partially rufous and 

 also the middle of the base of each elytra. It has the most smoothly 

 sculptured thorax of any species in our fauna. 



Occurs in Texas and Arizona. 



B. obsoletus, Say, Cure, p. 3; Am. Ent, Edit., Lee, p. i., n. 261 ; obteclus, 

 Say, Cure, p. 1 ; Am. Ent., p. 259; fabce, Riley, Annual Report, Ins., Missouri, 

 1871, p. 52 ; varicornis, Lee, mss. — Form moderately robust, color black or very 

 dark piceous, moderately shining, clothed with dark cinereous pubescence, ab- 

 domen dull rufous. Head black, opaque, finely punctured, sparsely pubescent 

 front feebly sub-carinate. Antennas slightly longer than head and thorax, 

 sub-serrate, black, four basal and the terminal joint rufous. Thorax one-third 

 wider at base than long, moderately convex, sides arcuate and gradually nar- 

 rowed to tip, base lobed at middle, lobe slightly emarginate; surface coarsely 

 and sparsely punctured, a slight longitudinal impression in front of scutellum, 

 moderately clothed with coarse dark cinereous pubescence, paler along the 

 median line. Scutellum subquadrate, emarginate at tip, median line distinct, 

 cinereo-pubescent. Elytra conjointly not wider than long, disc feebly convex, 



