338 G. H. HORN, M. D. 



Since the publication of Cotalpa ursma, (Trans. Ent. Soc. 1817, 

 158) and the accompanying table of our species I have found that the 

 characters therein made use of are not by any means constant and there- 

 fore not to be relied on in separating the species. The mandibles 

 when widely opened afford a more certain indication than any other 

 organ, as may be seen in the following table. 



Mandible nearly straight on outer side (pi. Ill, fig. 30.) 



Mand'ble with triangular lobe beneath (fig. 30, a) ; body of uniform 



yellowish color ; thorax faintly punctured consobrina, Horn. 



Mandible broadly rounded on outer edge (figs. 28, 29, 31.) 

 Mentum nearly flat, very feebly emarginate in front. 



Mandible faintly toothed within (fig. 31); thorax sparsely punctured 



and similar in color with the elytra, yellow lanigera, Linu. 



Mandible with long tooth within (fig. 28) thorax coarsely punctured and 



bluish-black; elytra reddish-yellow ursina, Horn. 



Mentum concave in front and deeply emarginate. 



Thora.x with large deep punctures; elytra yellow pnncticollis, Lee. 



Thorax densely and confluently punctured ; elytra nearly 

 red granicoUis, Hald. /^Z- 5 



The last two species have the outline of the mandible when viewed 

 directly in front sinuous with the inner angle deflexed. The mentum 

 of consobrina has the sides less rounded than in any other of our spe- 

 cies and the anterior margin bisinuous, the middle being as prominent 

 as the angles; the surface is nearly flat but with a ridge extending 

 from the base of the palpi inward and backwards in an arcuate man- 

 ner becoming gradually fainter behind. 



OSMODERMA, Lepell. 



0. socialis, n. sp. — Castancous shining, head and thorax black, the latter 

 reddish or greenish bronzed. Head black, densely and finely rugose, vertex 

 slightly concave, frontal margin strongly rcfle.xed, in front of eyes a broad tri- 

 angular hd^n with the hinder edge sinuous. Thorax one-fifth broader than 

 long, broadest at anterior third, sides strongly rounded in front to anterior 

 third then gradually narrowed to base which is as broad as the thorax is long ; 

 hind angles obtusely rounded, base with broad lobe at middle; disc with me- 

 dian broad sulcus broader behind, limited on each side by obtuse ridges 

 which gradually approximate in front, and end each in a rather sudden but 

 small elevation ; on each side an obtuse elevation between the termini of the 

 ridges and the strongly rounded portion of the side ; surface evenly and sparsely 

 and not coarsely punctured. Scutellum with median impressed line, sparsely 

 punctured between the elytra and densely under the thoracic lobe. Elytra but 

 blightly longer than broad, finely wrinkled and coarsely punctured. Body be- 

 neath sparsely pubescent, black, terminal segments of abdomen piceo-rufous. 



Female. — Vertex flat, front with arcuate impression between the eves, anterior 

 margin not reflexed, surface coarsely scabro-punctate. Thorax similar in form 

 to the male but less broad anteriorly, middle with broad, shallow impression; 



