428 Coleopterological Notices, V. 



A, diTersicoUe. — Subparallel, convex, subalutaceons, the elytra pol- 

 ished, black, the pronotum and elytra piceous-black ; legs and anteunse pale 

 flavate, the latter toward apex and the posterior femora toward base dusky. 

 ^<?ac? two-thirds as wide as the prothorax, broadly, longitudinally biimpressed, 

 minutely, sparsely punctate ; ocelli small, separated by more than one-third 

 of the width ; eyes rather small ; antennse much shorter than the head and 

 prothorax, strongly incrassate toward apex. Prothorax large, rectangular, 

 one-third wider than the length ; sides parallel, broadly, feebly and evenly 

 arcuate ; apex broadly, very feebly arcuate, but slightly narrower than the 

 base ; disk strongly convex, even, impressed at the sides behind the middle, 

 very minutely feebly and rather sparsely punctate. Elytra about as long as 

 wide, just visibly wider than the prothorax and distinctly less than twice 

 as long ; humeri not exposed ; sides straight and subparallel ; apex broadly, 

 evenly, feebly arcuate ; disk not very coarsely but strongly, rather sparsely, 

 confusedly and subrugosely punctate. Abdomen with more than three exposed 

 segments. Length 1.7-2.3 mm. ; width 0.8-0.95 mm. 



California (Lake Tahoe) ; Nevada (Reno); Utah (southern). 



A very abundant species, remarkable because of the great sexual 

 disparity in the form of the prothorax. The description is drawn 

 from the male which has the sixth ventral strongly, transversely 

 convex but scarcely visibly elevated or thicker in the middle, and 

 the anterior tibiae prominent within at the middle and thence nearly 

 parallel to the apex and gradually strongly narrowed to the base. 

 The female has the prothorax nearly twice as wide as long and 

 more shining, the elytra broadly arcuate at apex and transversely 

 impressed before the tip of each, the sutural angles not visibly 

 modified. In cali/oj-nicum, of which I have a large series from 

 Lake Co., corresponding prothoracic differences are observable but 

 not so marked. The present species is allied to tihiale, but differs 

 in its smaller size, in coloration and in its much sparser punctuation. 



A. gilTJpennet — Narrow, parallel, convex, black, the pronotum piceous, 

 sometimes decidedly paler at base; elytra and legs flavate; antennse pale, 

 dusky in outer half; surface strongly shining, the pronotum not distinctly 

 alutaceous. Head transverse, large, five-sixths as wide as the prothorax, 

 rather strongly, longitudinally biimpressed, minutely, sparsely punctate ; eyes 

 large and prominent ; ocelli separated by more than one-fourth of the width ; 

 antennse rather feebly incrassate in apical half, about as long as the head and 

 prothorax, the sixth joint quadrate, seventh similar biit a little larger, eighth 

 slightly wider than long, the tenth distinctly transverse. Prothorax trans- 

 versely rectangular, two-fifths wider than long ; sides parallel, nearly straight, 

 convergent and rounded in apical third ; base slightly wider than the apex ; 

 basal angles slightly blunt ; disk transversely, strongly convex, with feeble 

 traces of an impressed median line, feebly impressed laterally behind the 



