Casey — Observations on the Staphylinidae. 365 



terizing the majority, seem to be characteristic of the warm- 

 er parts of North and South America, and it is therefore 

 rather surprising to find the European fauna possessed of a 

 genus of this particular group, composed of several species 

 wholly foreign to the new world, excepting one — the EuUssus 

 fulgidus, of Fabricius, — which has been artificially introduced. 

 The following twenty-four genera are differentiated and 

 characterized principally by structure of the maxillary palpi, 

 form of the side margin of the prothorax and of the gular 

 sutures, structure of the basal part of the antennal funicle, 

 degree of separation of the middle coxae and form of the an- 

 terior tarsi, the hind tarsi varying but slightly throughout. 

 They may be briefly outlined as follows : — 



Fourth joint of the maxillary palpi long, never very much shorter than the 



third ; anterior tarsi always slender, subglabrous beneath 2 



Fourth joint small, much shorter than the third, and, at base, conspicuously 



narrower, conical and acuminate or aciculate and usually more 



oblique 19 



2 — Fourth joint stouter at base and less conspicuously narrower than the 



third 3 



Fourth joint more slender, its base much narrower than the tip of the third 



joint; side margio of the prothorax as in Xantholinus 16 



3 — Pronotum without dorsal punctures; middle coxae always distinctly 



separated ; gular sutures united ... 4 



Pronotum with dorsal punctures which are always sparse and for the most 



part arranged in a few series 10 



4 — Second antennal joint much shorter than the third; side margin of the 



prothorax deflexed anteriorly from the middle or posterior thereto; 



species usually large in size 5 



Second and third antennal joints equal, each slightly elongate but not as 

 long as the next two combined, nearly as in Xantholinus, the thoracic 

 side margin only feebly deflexed toward tip as in that genus 9 



5 — Neck nearly half as wide as the head 6 



Neck narrow, about a four th as wide as the head 8 



6 — Antennae very small, with the basal joint relatively much elongated 



and fully two thirds as long as the remainder; middle coxae rather 

 small, narrow, very widely separated; body large, subimpunctate, gen- 

 erally metallic blue or green in color, the elytra with very few punc- 

 tures, the abdomen distinctly though sparsely punctured; epistoma 

 subcoriaceous and testaceous in color, separated from the front by a 

 feeble transversely arcuate depression; labrum small, deeply sinuate at 

 the middle; mandibles not impressed externally; maxillary palpi mod- 

 erate, the fourth joint scarcely longer than the third, obliquely and 

 obtusely acuminate only toward apex; under surface of the head flat- 

 tened, the lateral margins but feebly prominent beneath, the sides 



