AMERICAN COMPONENTS OF THE TENTYRIIN^ 483 



The description of the antennas given by LeConte and Horn 

 in the classification, is unaccountably erroneous. 



Usechus Mots. 

 The species of this genus are few in number and live under 

 the loose bark of fallen trees, the two before me may be briefly 

 defined as follows : — 



Form stout, oblong-oval, blackish-piceous to paler in color, rough but 

 with the surface somewhat shining ; head small, simply, moder- 

 ately coarsely and sparsely punctate above and beneath, each punc- 

 ture with a short stiff yellow hair ; prothorax as long as wide, 

 widest and laterally subangularly prominent at the middle, the 

 sides thence strongly converging and nearly straight to the apex 

 and feebly converging and bisinuate to the basal angles, which 

 are right and not rounded ; base broadly, arcuately lobed, sinuate 

 near the angles, much wider than the apex, which is evenly and 

 feebly sinuato-truncate from side to side ; disk feebly impressed 

 along the middle from the apex, more broadly posteriorly, the 

 impression obsolete near basal third, the sides of the impression 

 feebly prominent, the entire surface coarsely but not densely tuber- 

 culose and with an elongate-oval pit at the middle of the base, the 

 side margins strongly reflexed throughout the length ; prosternum 

 with coarse tubercles like those of the upper surface, each tuber- 

 cle throughout with a stiff yellow hair; elytra one-half longer 

 than wide or less, a little wider than the prothorax and three- 

 fourths or more longer, the sides parallel and feebly arcuate from 

 the unrounded, reflexed humeri to the subapical tuberosity, the 

 apex between the tubercles parabolic ; surface with coarse grooves, 

 which are very coarsely punctate, the alternate intervals carinate, 

 the short yellow hairs more abundant on the ridges ; abdomen 

 very coarsely, not densely pimctate. Length 3.1-^.5 mm.; 

 width 1. 4-2. 1 mm. California (Mendocino to Sta. Cruz). 



lacerta Mots. 



Form less stout and very much smaller in size, brown-black to piceo- 

 testaceous, dull in lustre : head finely and sparsely punctate ; pro- 

 thorax nearly similar in form but with the impression obsolete 

 near the middle, with the basal pit deeper and more circular, 

 the antennal foss« extending further posteriorly and to a slight 

 distance behind the middle, and the tubercles above and beneath 

 smaller, feebler, denser and less well defined, the pubescence 

 longer and rather finer; elytra similar in general form and coarse 

 sculpture, the ridge nearest the suture much swollen at base as 

 in lacerta^ the pubescence longer and more nucleated in spots 

 along the ridges and denser on the basal enlargement of the inner 

 ridge; abdomen strikingly different in sculpture, being almost 

 impunctate toward the sides and much more finely punctured 

 elsewhere, except on the basal segment : impression of the fifth 



