540 CLASS VIII. 



Dry ops OLIV., Parnus FABR. Antennae frontal, very short, 

 with ten or eleven joints, auriculate, with second joint large, cover- 

 ing the rest. Mandibles not exsert. Maxillae with two laciniae, 

 the internal not broader than the external. Tarsi with five joints, 

 the last joint and claws strong. Body pubescent and pilose. 



Helichus ERICHSON, Dry ops LEACH, Parygrus ERICHS., Parnus 

 FABR., ERICHS. 



Sp. Dryops auriculatus OLIV., LATH., Parnus prolifericornis FABR., PANZER 

 Deutschl. Ins, Heft 13, Tab. i, Cuv. R. Ani., ed. ill., Ins. PI. 37, fig. 5 ; 

 2^'" long, black-brown, feet brown, covered with a silky glistering felt : 

 this insect lives at the bottom of fresh water, amongst the roots of water- 

 plants. 



Potamophilus GERMAR, Hydera LATR. 



Elmis LATR. Antennae mostly with eleven joints, filiform or 

 scarcely incrassated towards the apex. Maxillae with two horny 

 laciniae, the external narrow, palpiform. Feet elongate, tarsi with 

 five joints. 



Sub-genera: Limnius MUELL., ERICHS., Stenelmis LEON DUFOUR, 

 &c. 



Macronychus MUELL., LATR. Antennae sexarticulate, with last 

 joint oval, forming capitulum. 



Sp. Macron, quadrituberculatus, GERMAR Faun. Ins. Ewr. x. Tab. 4, GUERIN 

 Icon., Ins. PI. 20, fig. 4. 



Georissus LATR. Antennae short, with nine joints, clavate, 

 with club globose, triarticnlate. Head nutant. Body globose, 

 apterous. Elytra connate. Tarsi with four joints. 



Fig. PANZER Deutsckl. Ins. Heft 62, Tab. 5, GERMAR Faun. Ins. Ewr. 

 Fasc. 15, Tab. 3, GUERIN Icon., Ins. PI. 20, fig. 5 &c. Small insects, 

 scarcely -|"' long, living on the banks of rivers and streams. 



Family LXI. Palpicornia. Antennae short, with six to nine 

 joints, inserted in a deep sinus under the lateral margin of head, 

 terminated by a club perfoliate or solid. Palps filiform, unequal, 

 labial shorter, maxillary nearly of the length of antennae or some- 

 times longer than antennae. Body gibbous, mostly hemispherical 

 or oval. Mentum large, clypeiform. 



Sphceridium FABR. Maxillary palps nearly of the length of 

 antennae, with four joints, the first small, the second incrassated, 

 obconical. Maxillae with two laciniae membranous or coriaceous. 



