The front wings are modified into a protective shell that covers the back. These wing covers are called elytra. When not in use, the wings are folded over the back and cover the abdomen. The elytra meet in a straight line down the middle of the back. Sometimes, a triangular plate, the scutellum is visible where the wings meet, but it is usually much smaller than in Hemiptera.

Burrowing Water Beetle (Noteridae)

Mouth parts of Predaceous Diving Beetle (Dytiscidae)

Mouth parts are adapted for biting and chewing, rather than piercing and sucking. Although many water beetles are predators, they can not bite people, so they can be handled safely. This is good because their hard shell and rounded bodies make them very difficult to pick up with forceps unless you can get them by a leg.

Beetles have complete metamorphosis. The larva usually resemble worms or slugs, with slender legs. The larvae do not look at all like adult beetles. Sometimes the larvae have large hook-like jaws for catching prey. Also, the larvae of some species have long filaments on their abdominal segments that make them look like hellgrammites.

Water Beetle Larva 8 mm long.

Most beetles live on land, but a few families live in water in both their larval and adult stages.

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Burrowing Water Beetles

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