AMERICAN COLEOPTERA. IGl 



Z. tristis, black, subopaque; head coarsely and sparsely jmnctnred : thorax 

 slightly longer than wide, coarsely and sparsely punctured on the disk, more 

 densely at the sides; sides subangulate before the middle, posteriorly crenulate. 

 Elytra elliptical, moderately convex, base slightly emarginate, angles distinct, 

 surface roughened, with slightly elevated, smoother tubercles, on one side of 

 each a fine puncture, from which arises a minute yellow scale-like hair; apex 

 of elytra bituberculate, suture elevated at apex, groove short. Beneath as in 

 concolor. Length .55 — .85 inch. 



Lkcoxtb, Ann. Lye. V, 130. 



This species resembles concolor more decidedly than it does any other 

 species, but may be readily distinguished by the characters above 

 given. The smooth elevated spots have a stronger tendency to a linear 

 arrangement, the interspaces are well marked, and the elevations them- 

 selves much less convex than in concolor. The humeral angles are 

 more distinct, and the space between them distinctly broader than the 

 base of the thorax. The groove at the apex of the elytra is shortened 

 behind, allowing the tubercles and the sutural elevation to join. In 

 some specimens there is also a slight longitudinal thoracic impression. 



This species is not rare in Arizona. In my .sojourn in that region, 

 eighteen individuals were found. Those captured at Fort Grant lived 

 under the dead bark of Mesquite, others on the Maricopa desert, were 

 under the dead trunks of Cereus giganteus, another was found at Yu- 

 ma in my tent. A short time since, I received a specimen, from which 

 the larger measurement was taken, from Mr. Wm. M. Gabb, collected 

 from near the upper end of the peninsula of Lower California. This 

 differs in no other particular than size, from the specimens from Yuma 

 and Arizona. 



Z. opacus, black, opaque ; head finely and sparsely punctured; thorax longer 

 than broad, sides moderately rounded in front of the middle, posteriorly crenu- 

 late, base subtruncate and narrower than the apex; above coarsely and densely' 

 punctured; elytra elliptical, moderately convex, with very fine granular eleva- 

 tions arranged in irregular longitudinal series, with a fine puncture at the base 

 of each granule, from which arises a very short scale-like hair. Apex of elytra 

 bituberculate, sutural elevation prolonged, groove deep. Beneath sculjjtured as 

 in the two preceding species. Length .85 inch. 



This species may be readily distinguished from any others of the 

 genus known, by the peculiar sculpture of the elytra. The punctures 

 of the thorax have, in many instances, a slight elevation of their mar- 

 gin on one side, giving a granulated appearance to the surfoce. The 

 humeral angles of the elytra are le.ss distinct in this than the two pre- 

 ceding species, and the bases of the thorax and elytra are equal. 



This species is found in Nevada, probably near the southern boun- 

 dary. For the specimen in my possession I am indebted to Mr. John 

 Akhurst, of Brooklyn; another remains in his cabinet. 



TR.\NS. ASIER. ENT. SOC. (21) JULY, 1867. 



