94 COLEOPTERA OF NORTH AMERICA. 



and are gregarious; they are remarkable for the smooth shining 

 surface, almost destitute of hairs or punctures. The anterior and 

 middle tarsi are 4-jointed, and posterior ones 5-jointed; the first 

 joint of the hind tarsi is elongated; the thorax is distinctly mar- 

 gined. The labial palpi have but two joints. The middle coxie 

 are widely separated. 



It is prudent for the present to refer all of our species to 

 Gyrophajna. G. geniculata Mteklin, which has been placed in 

 Agaricocharia, is probably a species of Eudera. 



Group III. — Gymnusae. 



In this group the lobes of the maxilltc are long and slender, 

 the inner one is entirely corneous, serrate internally, and hooked 

 at the apex. The maxillary palpi have the second and third 

 joints very long, and the fourth not very distinct. The head is 

 deflexed, pointed in front; the antennae slender; the thorax and 

 elytra broad, and the abdomen strongly but gradually narrowed 

 behind, so that a form is assumed approaching that of some 

 members of Tachyporini. 



Tarsi 5-jointed ; labial palpi long, 3-jointed. Gymnusa. 



Labial palpi setaceous, with two indistinct joints ; anterior tarsi 4-jointed, 



posterior ones 5-jointed ; ligula short, entire. Mylleena. 



Labial palpi large, 3-jointed, last joint very small ; tarsi 3-jointed ; ligula 



large, bifid ; lobes nearly as long as the palpi. Dinopsis. 



Tluis far species have occurred only in the Atlantic States; 

 they are found in very wet places. Two species of Gymnusa 

 occur in the Canadian and Lake Superior regions, both identical 

 with the European species. 



Tribe II.— STAPHYLIIVIIVI. 



In this tribe the spiracles of the prothorax are visible, but the 

 antennae are situated at the anterior margin of the front, and 

 differ in position in the three sub-tribes. The anterior coxae are 

 lar;>-e and conical ; the trochanters of the hind legs are promi- 

 nent; the abdomen is strongly margined. 



Lateral margin of the thorax simple. Quediini. 

 Lateral margin of the thorax double ; 



Antennae distant. Staphylinini. 



Antennae approximated. Xantholinini. 



