Insect identification > Coleoptera > True Coleoptera > Carnivorius diving beetles

Carnivorius diving beetles

Family Dytiscidae (carnivorous diving beetles). - Members of this family are present in almost every quiet stream and pond. They are oval, rather flat beetles, usually black, and good swimmers, the hinder pair of legs being broad and somewhat oar-like and heavily fringed with hairs. The antennae are thread-like.

Whenever they need air, they float up to the surface of the water and allow the hinder end of the body to project a little out of the water. Then, lifting the elytra slightly, the air enters the space under them and is retained there aided by hairs present. The insect can now stay under water until this air supply has been exhausted. The larvae, often called "water tigers," they are such voracious creatures, feed, like the adults, on various water insects and other animals, even attacking small fish.

Some of this family may be at least an inch and a half long.