162 GEO. H. HORN, M. D. 



Through the kindness of Mr. Ulke I have been permitted to exa- 

 mine a specimen of this species from his cabinet. It differs from the 

 type only in being smaller, and with the granules less distinctly marked. 

 This obliteration of sculpture is probably the result of age in the spe- 

 cimen. While at Fort Tejon, California, I had abundant opportunity 

 of examining the Phloeodes of various ages, and found that while in 

 those of the present season were sharply sculptured, and the granules 

 very distinct, those of the preceding seasons were comparatively smooth. 

 As all these insects live under bark on logs and stumps, it is probable 

 that the smoothness of some is merely the result of mechanical action. 



Z. gracilis, black, shining; head finely and sparsely punctured; thorax fine- 

 ly and sjiarsely punctured, sides subangulate, before the middle slightly sinu- 

 ate, posteriorly finely crenulate; base narrow, subtruncate ; elytra elongate, 

 oval, surface very slightly rugose, and with striae of fine, rather distant punc- 

 tures, in each of which is a short, scale-like golden hair. Apex bituberculate, 

 groove broad. Prothorax beneath coarsely and densely punctured. Abdomen 

 sparsely punctured. Length .63 inch. 



This species may be readily distinguished by its slender form and 

 almost total absence of elytral sculpture. It is more glossy than any 

 of the already described species. The bases of the thorax and elytra 

 are nearly etjual in width. In all of the preceding species the basal 

 margin of the thorax is slightly elevated, and with a slight groove in 

 front of the elevation 5 this totally disappears in the present species. 



This species inhabits Arizona, in the neighborhood of Fort Whipple, 

 where it was collected by Dr. Coues, who placed it at the disposal of 

 Mr. Ulke, to whom Dr. Leconte is indebted for the only specimen of 

 this fine species now in his cabinet. 



In order to render the species now known, easily determinable, the 



following synoptic table is added : — 



Elytra quadrituberculate at aj^ex nodulosas, Solier. 



Elytra bituberculate at apex. 



Elytra with smooth elevated tubercles. 



Tubercles round, very convex, approximate and 



shining concolor. Lee. 



Tubercles round, flattened, distinct and subopaque...guttulatus, Horn. 



Tubercles elongate, flattened, moderately shining tristis, Lee. 



Elytra finely granulate opacus, Horn. 



Elytra finely punctured gracilis, Horn. 



