Nearly all beetles have four wings, the upper pair being hard and shell-like.
Metamorphosis is complete, the life stages being the egg, larvae, pupa, and adult.
Both the larvae and adults have chewing mouthparts. The larvae of beetles are often called grubs. Beetles are found almost everywhere. For example, whirligig beetles and diving beetles live in water, whereas cucumber beetles, the Mexican bean beetle and alfalfa weevil feed on vegetation. Others, such as scavenger beetles, live on dead animals.