CLASS V. IKSiiCTA. 185 



*** Elyti'a externally striated. Body zoithout punctures. 

 Sp. 3. Plat, depressum. Leach. H. depressiis. Marsh. 



Subdivision 3. — Antennae straigJd, not inserted in the cavity of the eyes. 



Feet semicontractite. 



Genus 139. LIMNIUS. Muller, GylL, Leach. Dytiscus. Panz. 

 CiiRYSOMELA. Mursli. Elmis. Lutr. 

 Antenna nearly filiform, the last joint largest, somewhat oval. 



Sp. 1. IJm. Volckmari. Leach. 

 Dytiscus Volckmari. Panzer. 

 Chrysomela buprestoides. Marsh. 



Fam. XVIIL Parnid.t:. Leach. 



Antenna inserted in the anterior canthus of the eye : elytra not shorter 

 than the abdomen. 



Genus 1-tO. PARNL^^S. Fabr., Illig., Marsh., Leach. Deemestes. 

 Geoff. Elater. Rossi. Dryops. Oliv., Lam., Latr. 



Antenna composed of three joints, the last joint articulated : tarsi with 

 five joints. 



Obs.' — The insects of this genvis inhabit the roots and blades of grass 

 at the sides of ponds and ditches ; the method of finding them is 

 to loosen the grass in those places, by which means the insects will 

 be found floating on the water : we have several species in this 

 country that have not yet been clearly defined, but have been con- 

 founded with prolij'ericornis. 



Sp. Af Par. sericeus. Leach's MSS. (P/. 3. fig. 10. a. antenna magni- 

 fed.) 



Genus 141. IIETEROCERUS. Base, Fabr., Illig., Latr., Marsh., 



Leach. 

 Antenna composed of eleven joints, the seven last forming a dentate 



or serrated mass : tar^si with four joints. 

 Sp. 1. Het. inarginutus. Blackish villose; sides of the thorax and ab- 

 domen with spots on the elytra, margins of the abdomen, and feet 

 pale luteous. {Pi. 3. jig. 11.) 

 Inhabits marshy places, burrowing in the muddy and clayey banks of 

 ponds. 



Fam. XIX. IIelophorid.e. Leach. 



Mandibles without teeth at their extremities : body oblong : antenna 

 terminated by a club. 



Stirps 1. — Clypcus whole : maxillary palpi with the last joint thick and 

 oval. 



