62 • COLEOPTERA OP NORTH AMERICA. 



Itroader than those of the previous group, and are easily distin- 

 guished by the prominent eyes, and by the third joint of the 

 maxillary palpi being thickened. They live exclusively in fungi, 

 and are gregarious ; they are remarkable for the smooth shining 

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

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

 first joint of the hind tarsi is elongated ; the thorax is distinctly 

 margined. The labial palpi have but two joints. 



Our species belong to Gyrophaena, which is distinguished from 

 the other genera of the group by the entire ligula, and the very 

 short second joint of the labial palpi. 



Group III.— Gymnusee. 



In this group the lobes of the maxilla? 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 the next tribe. 



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

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



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

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



Thus far species have occurred only in the Atlantic States ; 

 they are but three in number (one Myllasna, two Dinopsis), and 

 are found in very wet places. 



Tribe II.— TACHYPORItfl. 



The prothoracic spiracles are visible ; the anterior coxa? are 

 large, conical, and prominent, with the trochanters very distinct. 

 The antennae are inserted under the lateral margin of the front. 



The species are usually convex, with the thorax always ample, 

 arched, and highly polished, and the abdomen conical, sometimes 

 very short. They are found partly in fungi, partly under bark. 



Our genera are easily distinguished by the following table : — 



A. Antennae 10-jointed, tarsi 4-jointed (body very small, convex). 



HYPocyrTtJS. 



