STAPHYLINID/E 175 



parallel, with evenly and feebly arcuate sides and rather strongly, sub- 

 equally rounded base and apex, the median line only moderately widely 

 and rather feebly impressed, more finely anteriorly and posteriorly; 

 elytra parallel, as long as wide, scarcely more than a fifth wider and a 

 third longer than the prothorax, the humeri only very narrowly exposed 

 at base; abdomen at base two-thirds, near the apex not quite, as wide as 

 the elytra, the fourth and fifth tergites subequal in length; legs long and 

 slender. Length 1.8 mm.; width 0.32 mm. Ohio (Cincinnati), Chas. 

 Dury. 



Belongs to the cavicollis and Carolina group of very small delicate 

 species, in which the pronotum is more or less conspicuously and 

 broadly impressed along the middle in the female, though scarcely 

 at all in the male; it differs from Carolina in the much feebler pro- 

 notal impression, larger prothorax and more slender antennae; 

 from the male of cavicollis it differs in its less transverse prothorax 

 and larger head. 



Tachyusa vaciva n. sp. Rather slender, convex, shining, black, 

 the elytra scarcely paler but with a fine pale apical border, the abdomen 

 faintly rufescent basally, the legs piceous-brown; punctures fine, sparse 

 on the head, closer and becoming rather dense and asperate toward base 

 on the pronotum, asperate and close on the elytra, very sparse and with 

 long pubescence on the abdomen, except behind the third tergite, where 

 they become minute and dense and with shorter, denser pubescence, the 

 latter anteriorly moderately long and coarse, palish; head notably small, 

 almost as long as wide, much narrower than the prothorax, the eyes promi- 

 nent, at their own length from the base, the much less prominent tem- 

 pora at first feebly converging, than broadly rounding to the base ; antennae 

 pale, infumate and moderately incrassate distally, extending to the middle 

 of the elytra, the first three joints subequal in length, fourth two-fifths, 

 the fifth one-half, longer than wide, tenth as long as wide, the last not quite 

 as long as the two preceding, obtuse at tip; prothorax just visibly wider 

 than long, widest at two-fifths from the apex, where the sides are broadly 

 rounded, thence rounded and strongly converging to the apex and just 

 visibly converging and straight to the base, the latter broadly rounded, 

 much wider than the rectilinearly truncate apex, the median line moder- 

 ately impressed from before the middle nearly to the base; elytra as 

 long as wide, parallel, arcuately narrowing apically, two-fifths wider 

 and longer than the prothorax, the humeri moderately widely exposed 

 at base; abdomen at base three-fifths, at the apex of the third tergite 

 four-fifths, as wide as the elytra, the fourth and fifth tergites equal in 

 length. Length 2.8 mm.; width 0.45 mm. California (Dunsmuir, 

 Siskiyou Co.), Wickham. 



In this, as well as the types oifaceta and vespertina, the sixth ventral 

 is evenly rounded behind and they are therefore probably females, 

 but quite different in aspect from the Atlantic species; the present 



