Casey — Observations on the Staphylinidae. 261 



American genera of Phytosi are Bryobiota, Thinusa, Bryo- 

 fhinusa, Amblopusa, Diaulota and Liparocephalus, the 

 European being Phytosus, Actocharis, Acfosus and Arejia. 

 Tliey inhabit ocean beaches in various parts of the northern 

 hemisphere, being especially abundant on the western coast 

 of America, but extremely rare on the nearctic Atlantic 

 coast, the single species described by Dr. Horn, under the 

 name Phytosus litloralis, being unknown to me at present ; it 

 is possibly not a true Phytosus. 



Subtribe Bolitocharae. 



This is probably the largest subtribe of the Bolitocharini 

 and is apparently more developed in the palaearctic than in 

 the nearctic regions, owing to the very large number of min- 

 ute obscure species of Sipalia, which genus is exceedingly 

 rare in America, the somewhat aberrant Sipalia frontalis 

 Csy., of California, being the only one described thus far. 

 This deficiency is, however, made up largely by the greater 

 number of American species allied to Bolitochar'a, although 

 that genus itself does not occur here. There are two toler- 

 ably well defined groups of the subtribe Bolitocharae, the first 

 characterized by a broader obtuse mesosternal process, nar- 

 rower and more acute however in Stictalia, and more elongate 

 basal joint of the hind tarsi, the second having an acute pro- 

 cess and shorter basal joint, generally but little longer than 

 the second, though as long as the next two combined in 

 Euryusa, and comprising in addition thereto, the genera 

 Silusa, Leptusa, Sipalia and others which will not be system- 

 atically discussed in the present paper. The antennae are 

 variable in the first group but are always gradually thicker 

 to the tip in the second. The Bolitocharae, as a group, have 

 a readily recognized facies owing to their coarse asperate 

 sculpture, and, as far as known to me, live exclusively in 

 fungi of various species, frequently in enormous numbers. 



The genera of the first group indicated above may be 

 briefly defined as follows : — 



Prothorax distinctly narrower than tiie elytra; antennae gradually thicker 

 to the apex 2 



