CLASS V. IXSECTA. 187 



Oeniis 148. HYDROBIUS. Leach. 

 Bodi/ ovalj convex, obtuse : ej/cs simple. 



* Elytra striated, 

 Sp. 1. Jiydr. fiiscipes. 

 Inhabits ponds. 



** ElT/tra smooth. 

 S;". 1. Hi/dr. melanocephahts. 

 Inhabits ponds. 



B. Elt/ti'a, icith the apex truncated. ScitteUiim small. 



Genus 119. LIMNEBIUS. Leach. 

 Bodi/ rather depressed : ej/es simple. 



Sp. 1. Lii7i. nitidus. Hydrophilus nitidus. Marsh. 

 Inhabits ponds and ditches. 



Stirps 3. — Cli/pcus whole : sternum produced into a spine. 



Genus 150. HYDROUS. Lhmcs ALSS., Leach. 

 Sctddlion large : anterior tarsi of the male dilated in the middle with un- 

 equal claws: antenna With, their last joint acuminated. 

 Sp. 1. tfijdr. piceus of authors. 

 Inhabits ponds and ditches. 



Genus 151. HYDROPHILUS of authors. 



Bodi/ with the posterior part slightly obtuse: antenn<B with the last 

 joint obtuse : scutellum moderate : anterior tarsi in both sexes simple. 

 Sp. 1 Hj/dr. caraboidcs of authors. {PI. 3. Jig. 16.) 

 Inhabits ponds ; is very common. 



Fam. XXI. Sph^ridiad^. Leach. 



Antenna terminated by a club : maxillari) palpi very long : mentum large, 

 clypeiform: head with the front rounded, cowl- shaped: feet formed 

 for walking : tarsi with the basal joint as long or longer than the 

 second joint (in the male with the last joint on the anterior tarsi 

 large). The insects of this family are very nearly akin to the ify- 

 drolophii. 



Genus 152. SPIL^LRIDIU^I. Fahr., Oliv., Lamarck, Leach. Der< 



MESTES. Linn., De Geer, Marsh. 



Body somewhat ha-mispheric : eyes immersed : thora c transverse ; tibitt 



spinose, armed with heels : sternum behind produced into a conic 



spine. 



Sp. 1. Sph. scarabitoidcs. Black, shining, smooth : scutellum forming a 



long triangle : feet very spiny : each elytron at the base with a blood- 



