98 MEMOIRS ON THE COLEOPTERA. 



distally, pale and still notably stout basally, the first joint strongly com- 

 pressed, much longer than the second, the third short, distinctly shorter 

 than the second, obconic and less than one-half longer than wide, fourth 

 strongly transverse, the tenth not quite twice as wide as long, the last 

 large, ogivally pointed, much longer than the two preceding; prothorax 

 nearly three-fifths wider than long, the sides parallel and strongly, sub- 

 evenly arcuate, the base rounded with the angles very obtuse and rounded, 

 the surface wholly unimpressed; elytra moderately short, with straight 

 diverging sides, at base not evidently wider, the suture fully a third longer, 

 than the prothorax; abdomen a little narrower than the elytra, sub- 

 parallel, with slightly arcuate sides, very feebly narrowing apically, 

 the fourth and fifth tergites equal. Length 1.5 mm.; width 0.4 mm. 

 Pennsylvania (near Philadelphia). 



Allied to the last but very different in the basal parts of the an- 

 tennae and the less rapidly incrassate apical parts, in its smaller 

 eyes and in coloration ; the sixth tergite of the female is very broadly 

 and evenly rounded at apex. 



Atheta vacillans n. sp. Moderately stout, subparallel, shining, blackish- 

 piceous, the head and abdomen black, the latter with the apex and apices 

 of the basal tergites paler; elytra pale piceo-flavate throughout, the legs 

 pale; punctures feeble, asperulate, not at all dense, very sparse on the 

 abdomen, the vestiture rather long, palish; head large, rather transverse, 

 four-fifths as wide as the prothorax, the tempora tumid, as prominent 

 as the eyes and nearly two-thirds as long, the fine carinse not quite entire; 

 antennae rather short, gradually incrassate and dusky distally, slender 

 and pale basally, the second joint more cylindric but scarcely so long as 

 the third, which is more than twice as long as wide, fourth barely at all 

 shorter than wide, the tenth one-half wider than long, the last acutely 

 ogival, equal in length to the two preceding; prothorax rather more than 

 one-half wider than long, parallel, the sides feebly rounded, becoming 

 straighter basally and a little more converging at apex, the median line 

 slightly impressed throughout; elytra short, with diverging and nearly 

 straight sides, at base very evidently wider, the suture a third longer, 

 than the prothorax; abdomen narrower than the elytra, parallel, with 

 nearly straight sides, the fifth tergite but little longer than the fourth. 

 Length 2.5 mm.; width 0.68 mm. Rhode Island (Boston Neck). 



This species seems to be allied most closely to dama, differing in the 

 much larger head, more congested tempora and shorter prothorax; 

 from comitata, which occurs in the same locality and also has a no- 

 tably large head, it may be known at once by the congested tempora 

 and more slender antennae, as well as the relatively smaller pro- 

 thorax. The mesosternal process is not aciculate but very narrowly 

 rounded at tip and separated from the angulate metasternum by 

 much less than a third of the width of the middle femora, the coxae 

 not very approximate. 



