CLASS V. INSECTA. 
187 
Genus 148. HYDROBIUS. Leach. 
Lody oval, convex, obtuse : eyes simple. 
* Elytra- striated. 
Sp. 1. Hydr. fuscipes. 
inhabits ponds. 
** Elytra smooth. 
Sp. 1. Hydr. melanocephalus. 
Inhabits ponds. 
B. Elytra with the apex truncated. Scutellum small. 
Genus 149. LIMNEBIUS. Leach. 
Body rather depressed : eyes simple. 
Sp. 1. Lira, nitidus. Hydrophilus nitidus. Marsh. 
Inhabits ponds and ditches. 
Stirps 3. Clypeus whole ■ sternum produced into a spine. 
Genus 150. HYDROUS. Limit's MSS., Leach. 
Scutellum large : anterior tarsi of the male dilated in the middle with un- 
equal claws : antenna with their last joint acuminated. 
Sp. 1. Hydr. piceus of authors. 
Inhabits ponds and ditches. 
Genus 151- HYDROPHILUS of authors. 
Lodi/ with the posterior part slightly obtuse: antenna with the last 
joint obtuse : scutellum moderate : anterior tarsi in both sexes simple. 
Sp. 1 Hydr. caraboides of authors. {VI. 3. fig. 16.) 
. Inhabits ponds; is very common. 
Fam. XXI. Spilt, ridiad.e. Leach. 
Antenna terminated by a club : maxillary 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 Hy- 
drolophii. 
Genus 152. SPH/EREDIUM. Fabr., Oliv., Lamarck, Leach. Deu- 
mestes. Linn., De Geer, Marsh. 
B °dy somewhat hemispheric : eyes immersed: thorax transverse : tibia 
spinose, armed with heels : sternum behind produced into a conic 
spine. 
S P. 1. Sph. scarabicoides. Black, shining, smooth : scutellum forming a 
long triangle : feet very spiny : each elytron at the base with a blood- 
