AMERICAN COLEOPTERA. 145 



margin, the outer in addition toothed near the tip. Middle claws similar, each, 

 pectinate along a double margin. Posterior claws similar to the middle, the 

 two margins however so close as to appear almost as one. Posterior tibiae with 

 a few stiff hairs within, spurs slightly spatulate and pellucid at tip, the outer 

 much longer, tarsus longer than the tibia. 

 Female. — Unknown. 



The differences between this species and mucoreiis as learned from 

 the male are very feeble, consisting in the less angulated sides of the 

 thorax and the much less distinctly bipectinate character of the claws. 

 In obtusus there are moderately long hairs arising from the base of the 

 thorax and elytra not seen in our specimens of mucoreus, but these 

 may easily have been removed by accident. I retain the species for 

 the present as distinct more from its facies, in the hope that the dis- 

 covery of the female may teach more. 



One specimen, Kansas. 



li. opacicollis n. sp. — Subcylindrical, piceo-rufous, thorax darker and 

 opaque, surface distinctly pruinose, sparsely clothed with short erect hairs. 

 Head cribrately punctured, frontal suture not imjaressed, clypeus transverse, 

 feebly emarginate at middle, margin moderately reflexed. Thorax more than 

 twice as wide as long, narrower at apex than base, sides very obtusely 

 subangulate behind the middle, margin coarsely crenulate and fimbriate, 

 disc moderately convex, surface opaque, sparsely obsoletely punctate. Elytra 

 sparsely punctate and pubescent, surface pruinose, sutural costa feeble, discal 

 costa entirely wanting, margin fimbriate with moderately long hairs. Body 

 beneath moderately punctate, rather sparsely clothed with long whitish hairs. 

 Length .50— .56 inch; 12.5—14 mm. 



Jlfa/e.— Club of antennae longer than the funicle and paler. Abdomen with 

 segments three and five with moderately long hairs at middle, last three seg- 

 ments broadly concave. Pygidium moderately large, convex, shining, sjaarsely 

 punctate and subtruncate at tip. Claws similar on all the tarsi, each with a 

 small tooth at middle, the basal portion of the claw very finely serrulate, apical 

 portion simple. Posterior tibiae fimbriate within with moderately long hair, 

 the spurs slender, the outer one-fourth longer. Posterior tarsi longer than 

 the tibise. 



Female.— C\\xh of antennae slightly variable in length but always shorter 

 than the funicle. Claws on all the tarsi alike and precisely like those of the 

 male. Abdomen convex, smooth and convex at middle. Posterior tibise with 

 few hairs within, shorter than the male, spurs shorter, broader and more curved 

 than the male and pellucid at tip. Pygidium more narrowed at tip than 

 male, sparsely punctured, moderately shining. Posterior tarsi shorter than 

 the tibiae. 



This species is at once known by its opaque thorax. 



The specimens from Arizona and New Mexico have the thorax a 

 little less opaque than those from Utah, and the tarsi a little shorter 

 than in the $ from Utah, they agree however in all other characters, 

 and I am unwilling to separate them as distinct, but as these are all 



TRANS. AMER. ENT. SCO. VII. (19) NOVEMBER, 1S78. 



