Casey — Observations on the Staphylinidae. 145 



part of the mesosternal process truncate at tip as in tahoensis, 

 the other having this finely acuminate at tip as in americana 

 and other allied species. Thoracica was originally described 

 as a Baryodma^ only the fine tip of the central elevated part 

 of the mesosternal process being visible in the specimen de- 

 scribed and presenting the appearance of a low obtuse carina ; 

 there is no trace of real carina, however, and the species is a 

 true Aleochara. 



Aidocbara n. gen. 



This genus appears to replace Aleochara in the fauna of the 

 Pacific coast, although represented at present by only a single 

 small species. The general habitus differs from that of Aleo- 

 chara in being more parallel, with much greater development 

 of the head and more quadrilateral prothorax. It differs 

 further from Aleochara in the fact that the second antennal 

 joint is much longer and not shorter than the third and the 

 last joint, instead of being pyriform, is here shorter and evenly 

 pointed from near the base, scarcely longer than wide in the 

 type species. The mesosternal process differs in being very 

 much narrower, obtusely pointed at tip and somewhat abbre- 

 viated, extending to about apical fifth of the coxae, the 

 metasternal process being correspondingly longer, triangular 

 and about as long as wide ; it meets the mesosternal process 

 at apex in much the same way as in Aleochara^ and, similarly, 

 the mesosternum is without vestige of carina at any point. 

 The abdomen differs decidedly, being impressed only on the 

 first dorsal plate, the others being flat and evenly, more 

 closely and finely punctate throughout their extent. The type 

 may be defined as follows : — 



Moderately stout and convex, slightly shining, the surface very minutely 

 reticulate in addition to the punctuation, black, the entire elytra and 

 abdominal tip rufous; legs pale, the entire antennae darker, picec-tes- 

 taceous; head wider than long, fully three-fourths as wide as tluj pro- 

 thorax, finely, rather sparsely punctate, the eyes moderately large; 

 antennae very short, stout and compact, cylindrical beyond the middle, 

 with the pennliimate joints rather more than twice as wide as loner, not 

 as long as the head and prothorax, the latter one-half wider than long, 

 ODiy slightly narrower at apex than at base, the latter broadly and 



