[13] 



NORTH AMERICAN COLEOPTERA. 169' 



scutelham. Scutelhira very slightly wider than long Elytra at base as wide 

 as the pro thorax; sides strongly convergent to the apex, evenly and rather 

 feebly arcuate; apex feebly subtruncate, together rounded, each aDgle nearly 

 right and scarcely at all rounded; disk slightly less than one-half longer than 

 wide, two and one-third times as long as the prothorax, strongly convex, 

 finely, feebly reticulate, not visibly punctate. Eighth ventral segment large, 

 having two apical seta?; sixth broad y emargiuate. Length 1.3 mm. 



Texas; (Austin 1). 



This species, as may be inferred from the description, is 

 very closely allied to polita, but is well distinguished by the 

 form of the elytral apices; in addition the reticulations of 

 the elytra are finer and stronger in polita, and the punc- 

 tuation of the pronotum is less evident in angustula. It may 

 be considered unwarrantable to trust to the conformation of 

 the elytral apices for specific characters in the Hydrophili- 

 dre, but in the present instance there is much more proba- 

 bility of both the typical representations being of the same 

 sex, than that they are not, for the eighth segment in each 

 is large and very distinct and is provided in each with two 

 equal apical seta3. Angustula is a narrower and slightly 

 more convex species than polita, and has the prothorax 

 slightly less strongly transverse. 



All the species of the present genus have the two basal 

 punctures and the two apical rows of asperities; the prono- 

 tum is, in addition, always very finely margined along the 

 apex and sides, but not along the base, the latter being ab- 

 ruptly convex and narrowly declivous to the plane of the 

 elytra. 



L. alutacea n. sp. — Suboblong, moderately robust, not strongly convex, 

 black, piceous by diaphaneity; legs dark piceo-testaceous; palpi and antennas 

 slightly paler; pubescence extremely fine, recumbent, not dense above; in- 

 teguments alutaceous, elytra scarcely more strongly so than the pronotum. 

 Head scarcely one half wider than long, feebly convex, finely reticulate, very 

 minutely, sparsely punctate; epistomal suture transverse and very feeb'e in 

 the middle, oblique and almost completely obliterated at the sides; epistoma 

 with a small discal puncture near each apical angle. Prothorax at apex 

 slightly wider than the head, broadly, moderately and trapezoidally emargi- 

 nate, two-fifths wider than long; at base transversely truncate, broadly and 



