At 3.5 cm, the adult common cockchafer is the United Kingdom’s largest scarab beetle. The rusty brown beetle is also called the May bug because it tends to emerge from its underground home around May.

There are a few stories about how the common cockchafer got its name. One explanation says the word “cock” means familiar, and “chafer” means gnawing beetle. Another explanation says cockchafer is Old English for "big beetle." 

Yet another account suggests that the word cock in Old English referred to large size, while chafer meant gnawing insect. Therefore, the cockchafer got its name from its size and tendency to chew leaves and flowers vigorously.