HISTERID.E 247 



thick basally, very fine apically, the marginal stria very fine, turned in- 

 ward slightly at base; surface with minute sparse feeble punctures through- 

 out; elytra longer than wide, two-thirds longer than the prothorax, 

 much narrowed at apex and with strongly arcuate sides; fine sutural 

 stria abbreviated at anterior two-fifths, attaining the apex, a single 

 short and feebly oblique basal stria also evident; punctures small and 

 sparse though strong and conspicuous; flanks very smooth and polished; 

 pygidium with sparse and excessively minute punctulation; sides of the 

 metasternum and abdomen with small but strong, moderately sparse 

 punctures, the mes-episterna with slightly smaller and sparse punctures 

 throughout; four spinules of the anterior tibiae very small. Length 

 1.9 mm.; width i.o mm. Kentucky (Louisville). A single example, 

 having the pygidial surface wholly unmodified. 



Allied to the preceding and to seminulum, but rather larger than 

 either, and with the sides of the prothorax more strongly converging 

 and feebly arcuate to the relatively more narrowed apex; the pro- 

 thorax is much longer than in seminulum, corresponding with the 

 more elongate form of the body, but it is relatively no more elongate 

 than in nanulus, though more attenuated anteriorly. 



*Isolomalus durangoensis n. sp. Rather broadly oblong-oval, only 

 moderately convex, shining, black, the legs small and feeble, obscure 

 rufous; head evenly and feebly convex, very minutely, remotely punctu- 

 late, the apical beading entire; prothorax fully two-thirds wider than 

 long, the sides moderately converging, evenly and strongly arcuate from 

 base to apex, the marginal bead fine, subequal; surface minutely, feebly, 

 sparsely and evenly punctulate; along the base there is a single line of 

 small but strong punctures; elytra, not longer than wide, rapidly and 

 arcuately narrowed apically; fine sutural stria extending from the apex 

 for three-fifths, the oblique discal basal striae faint and barely traceable; 

 punctures fine and sparse but distinct, the flanks smooth; pygidium in 

 the type convex, having many coarse irregular anastomosing cracks 

 throughout the width in basal half, the remainder more convex, even and 

 with very fine punctures; sides of the abdomen rather strongly but 

 loosely punctate, the sides of the sterna extremely minutely and remotely 

 punctulate; the four or five denticles of the anterior tibiae are very small. 

 Length 2.2 mm.; width 1.28 mm. Mexico (Durango City, Durango), 

 Wickham. 



This species is allied to infimus Mars., of which I have a small 

 series from southern Mexico, but it is less broad and the sutural 

 stria completely attains the apex and is not posteriorly abbreviated 

 as it is in infimus. The sex of the type is probably female. 



*Isolomalus mysticus n. sp. Oblong-oval, rather strongly convex, 

 shining and black or piceous-black, the legs obscure rufous; head very 

 minutely, sparsely punctulate, the apical beading excessively fine but 

 entire; prothorax three-fifths wider than long, the sides rather strongly 



