ORDER COLEOPTERA. 411 



have their antennae uncovei'ed, not lodging in peculiar 

 cavities, a little longer than the head, with the first articu- 

 lation, almost as long as the following taken together, and 

 the second short and globular. The palpi are prominent, 

 the mouth is entirely naked, the presternum not advancing 

 upon it, a character exclusively peculiar in this tribe to this 

 sub-genus.* 



DiiYOPs (Proper), Oliv. Parnus, Fab., 



Whose antennae, shorter than the head, are received into 

 a cavity situated under the eyes, and covered, in a great 

 part, by the second articulation, which is large, dilated, in 

 the form of a palette almost triangular, and forms a pro- 

 jection in the manner of an auricle. From thence comes the 

 name Dertneste a oreilles, given by GeofFroy to the most 

 common species. The palpi are not projecting.-f- 



2nd. — Those whose antennae, composed of eleven articu- 

 lations, are filiform, or a little thicker towards the end, and 

 at least, almost as long as the head and corslet. 



Elmis, Lat. Lininius, Illig. 



Are found in the water, under stones, or on the leaves of 

 nenuphar. 



3rd. — Those whose antennae, always very short, present 

 but nine or six articulations, and which terminate in a knob, 

 almost solid, oval, or nearly globular. 



* Parnus acitminatus. Fab. Panz. Faun. Insect. Germ. VI. 8 ; Dryops 

 picipes, Oliv. III. 41. 1. 2. 



-f- Latr. Gen. Crust, et Insect. 55. Schcen. Synon. Insect. I. ii. p. 116. 

 The Dryops of Dumeril presents some differences in the length of the 

 feet, the form of the antennse, and the corslet, and after which Dr. Leach 

 has thought proper to form, with this species, a peculiar genus, Dryojis. 

 The other species enter into that of Panius, 



