1^25 



Philydrida, MacLeay. 

 Hydrophilid^, Leach. 

 Hydrophiloidea, Hope. 



1. Hydrous, Linneus. 



The species of this genus are much more nume- 

 rous than Entomologists are aware of, and from the 

 notes contained in my Journal I find, at least, 

 seventy species have fallen under my notice ; they 

 seem to be naturally divisible into three sub-genera, 

 1st. into true Hydrous, which has the wings 

 rounded at the apex and spineless. 2nd. Those 

 species which have the sutural apex of the elytra 

 more or less spined, to which I give the name of 



