26 MEMOIRS ON THE COLEOPTERA. 



Though allied to the preceding in its general structural features, 

 this species may be distinguished at once by its much smaller size, 

 narrower form, differences in the basal part of the antennae, much 

 larger head, less transverse and less convex prothorax, with much 

 less arcuate sides and relatively narrower elytra and abdomen; 

 it is represented by four examples and is compared with a series of 

 three of the preceding. 



Group II. 



There are but two species of somewhat similar facies entering 

 this group. 



Oxypoda mobilis n. sp. Moderately stout and convex, pale brown, 

 the head and abdomen more blackish, the legs pale; surface alutaceous, 

 the punctures fine and dense, coarser, more asperate and not so close on 

 the more shining abdomen; vestiture fine, decumbent and very short, 

 a little longer and less dense on the abdomen; head wider than long, 

 fully three-fifths as wide as the prothorax, slightly swollen at base, the 

 eyes somewhat convex and at three-fifths their length from the base; 

 antennae short, pale brown, rather stout, gradually distinctly incrassate, 

 the second joint slightly longer than the first or third, the fourth about 

 as long as wide, fifth to tenth transverse, the latter one-half wider than 

 long, the last ogivally pointed, as long as the two preceding; prothorax 

 three-fifths wider than long, rounded at base, the sides evenly and moder- 

 ately arcuate and feebly converging from the obtuse and rounded basal 

 angles to the apex, the surface with a small and very faint ante-scutellar 

 impression; elytra parallel, slightly shorter than wide, equal in width to 

 the prothorax, the suture two-fifths longer, the sinuses at apex distinct; 

 abdomen much narrower than the elytra, proportionally slender, gradually 

 moderately tapering and with straight sides from base to apex, the fifth 

 tergite one-half longer than the fourth; basal joint of the hind tarsi 

 elongate. Length 2.4 mm.; width 0.55 mm. Texas (El Paso). 



To be known by the relatively short prothorax, narrow and 

 gradually tapering abdomen and other characters as stated. 



I do not remember to have seen any allusion to the frequently 

 observable collapse of the last antennal joint, generally on its inner 

 side, appearing often to be a natural excavation but merely due to 

 shrinking of the integument on drying; it would seem to show that 

 the interior of this joint is less compact and loses more by drying 

 than that of the other joints. It is frequently very deceptive and 

 liable to be mistaken for a true structural character. 



Oxypoda rubescans n. sp. Rather stout, slightly shining and flavo- 

 testaceous, the head and abdomen blackish and more shining, the latter 



