AND EASTERN NEW MEXICO. 17 



scarcely wider than long, somewhat narrowed in front, slightly rounded on the 

 sides, bisinuate at tlie base, with the middle lobe broadly rounded. Elytra more 

 than three times as long as the thorax, parallel on the sides, obtusely rounded 

 behind, distinctly punctulate. Anal style slender. Posterior tibiae broad, with six 

 or seven very short oblique ridges on the supero-external margin ; first joint of 

 posterior tarsi not shorter than the tibia, with five similar oblique ridges; second 

 joint with two. 



M. dirisa, fusco-nigra, supra dense helvo-pubescens, elougata, postice subattenuata, capite thorace- 

 que ante medium rufo-testaceis, elytris evidenter punctulatis ; pedibus posticis, tibiis carinulis 2 

 vel 3 minutis obliquis, tarsorum articulo Imo tibia baud breviore carinulis 4, 2ndo duabus in- 

 structo ; autennarum basi pedibusque anterioribus rufo-testaceis, unguiculis simplicibus. Long. -11. 



Platte river: resembles M. marginalis (Mordella marc/. Say), but differs by the 

 pubescence being coarser, more abundant, and of a yellowish brown color. Tlie 

 thorax is a little wider than long, not narrowed in front, broadly rounded on the 

 sides, feebly bisinuate at ba.se; the anterior half, with the head is reddish yellow, 

 and the outline separating the yellow from the black is sinuate as in the species 

 above mentioned. 



In thus introducing the present genus into the fauna of the United States, a few 

 remarks regarding our numerous species of MordelUdce will be appropriate. Tlie 

 genera which they represent are five in number, and may be thus separated : — 



A. Seutellum quadratum, transversum postice subemarginatum Tomoxia Costa. 



B. ScutelUim triaugulare, apice rotundatum; 



a. Palpi maxillares articulo ultimo valde dilatato securiform! Glipa Lec. 



b. Palpi maxillares articulo ultimo triangular! ; 



Antennas articulis exteruis valde transversis, velutinis Bphalera Lec. 

 AntenuiE articulis externis triangularibus, baud transver.sis ; 



Pedes postici simplices llordella Linx. 



Tibite tarsique postici carinulis notati Mordellistena Costa. 



To Tomoxia belong M. hidentata Say, and a nearly allied smaller species. 



To Glipa belongs only M. Idlaris Say. The body is .slender; the outer joints of 

 the antennae triangular; the maxillary palpi elongated, with the last joint in the 

 form of an obtuse isosceles triangle, attached by its apex. The middle tibiae are 

 longer than the tarsi ; the posterior tibiae only moderately dilated, longer than the 

 first joint of the tarsi, and destitute of oblique ridges; the anal style is short, trun- 

 cate and subemarginate. 



Sphalera is the genus indicated, but not named by Lacordaire (Gen. Col. V, 609, 

 note). The only native representative known to me is M. melania Germ. 



To Mordella heloug Anasjns i-jyimckiia Say; M. S-2mnckda Fabr. ; ocidata Say; 

 insidata Lec; sercal Say; Anaspis trUobaSay; M. marrjinata Mels. ; lineata Mels.; 

 scutellaris Fabr. (atrata Mels.) ; undulata Mels., and four nondescript species. 



To Mordellistena belong all the other species described by Say, Melsheimer, and 

 myself; natural groups among them may be easily formed by the number and 

 position of the tibial ridges, and the arrangement of the colors of the upper surface. 

 M. sericans and one nondescript are remarkable by tlie posterior tibiae having a fine 

 carina extending along the upper edge, and only a single very long oblique ridge 

 3 



