WATER BEETLES. 



107 



tained in its larval stages as the " water devil " on 

 account of its voracity and destructiveness. Indeed, 

 it is a very difficult matter to keep the larvae, unless 

 we separate them. The fully-developed Dyticus leaves 

 the water during the night, in the summer months, 

 so that if the top of the aquarium be not closed, its 

 owner may be somewhat astonished at seeing some 

 of its aquatic inhabitants leaving it to dash themselves 

 against the gas-globes ! 



Fig. 57- 



Great Aquatic Beetle (Hydrophilus piceus). 



Hydrophilus or Hydrous picetts, or great aquatic 

 beetle, is the largest of our British species. It is in 

 wondrous contrast with the Dyticus in its habits, 

 for it is extremely inoffensive, and therefore well 

 suited to a fresh-water aquarium. Indeed, the full- 

 grown insect not unfrequently falls a victim to the 



