356 PROCEEDINGS OP THE ACADEMY OP 



by the stronger punctuation of the head and thorax. The form is about the 

 same as that of the preceding; the antennae are shorter than the head and 

 thorax, with the third joint slender, and the fourth not as wide as the fifth. 



26. P. r u f i p e n n i s. Dasytes ruf. Lee, Proc. Acad. Nat. Sc. Phila., 1858. 

 71. 



Arizona, Mr. Schott, one specimen. Much larger (6 mm.) than any of the 

 preceding, and remarkably different, by the elytra being rufous, and as finely 

 punctured as in P. suturalis. The tborax is equably, tolerably strongly 

 punctured, very little narrower than the elytra, wider than long, much rounded 

 on the sides, broadly rounded at base, with the hind angles obtuse, rounded 

 and not distinct. The scutellum and a small portion of the suture are black. 

 The erect hairs and pubescence are in great part wanting, but enough re- 

 mains to show that both are cinereous. The feet are rufous, and the anterior 

 tibia? are armed with a very distinct row of spines on the outer side. The 

 antenna? are wanting in the unique specimen before me. 



27. P. serricollis, niger nitidus, pube pallida parca elongata vestitus, 

 pilis erectis nigris pallidisque intermixtis, capite modice punctato, thorace 

 rotundato, convexo, fortiter, medio parce punctato, lateribus denticulatis, basi 

 latius rotundata ; elytris thorace baud latioribus fortiter sat dense punctatis, 

 rufo-testaceis ; anteunis nigro-piceis pedibus rufis. Long. 5-5 mm. 



Two males, New Mexico and Colorado. The sixth ventral segment is not 

 excavated. Of the same size as P. r u fi p e n n i s, but quite distinct by the 

 form of the thorax, which is but little wider than its length, very much 

 rounded at the sides and apex, and more broadly rounded at the base, with 

 the hind angles not very distinct. The sides are strongly serrate, especially 

 in front of the middle. The black hairs are long on the thorax, but on the 

 elytra the pubescence is intermixed with pale erect hairs, only a few black 

 ones being seen. 



27. P. serrulatus, nigro-virescens subnitidus, pube brevi albida minus 

 dense vestitus, pilis erectis nigris intermixtis, capite thoraceque modice punc- 

 tatis, hoc latitudine paulo breviore, antrorsum angustato, apice rotundato, 

 basi late rotundata, angulis posticis baud distinctis, lateribus serrulatis late 

 rotundatis ; elytris sat dense punctatis, transversim subrugosis ; antennis 

 nigro-piceis, ad thoracis medium extensis, extrorsum incrassatis, femoribus 

 piceis, tibiis tarsisque testaceis. Long. 4 mm. 



Arizona, Dr. Irwin. U. S. A. The joints of the antennas 4 10 are gradu- 

 ally wider and obtusely rounded at tip. The spines on the outer margin of 

 the anterior tibiae are distinct, but less prominent than in the preceding 

 species. 



LISTRUS Motsch. 



The chief difference between this genus and the preceding is to be found 

 in the anterior tibiae, which have not any spines on the outer margin. The 

 appendages of the claws are broad, as long as the claws themselves and connate 

 with them almost to the tip ; in this as well as in the form of the palpi and 

 antennae it agrees with Pristoscelis ; the thorax is scarcely one -half wider 

 than the head, and is always serrate and fimbriate at the sides ; the pubes- 

 cence is uniform in texture, without any intermixed erect hairs. 



The characters correspond with those ascribed to the European genu 

 Lobonyx, in the works of DnVal and Kiesenwetter, except that the antenna 

 are distinctly serrate, with the eleventh joint oval and not constricted at the 

 middle. 



The sexual characters are not observed in the anterior tarsi as in Lobo- 

 n y x, but in the fifth and sixth ventral segments, which are more or less fove- 

 ate or excavated in the male. 



The species in my collection may be separatedvas follows : 



[Dec 



BE 



