Oil Beetles

Meloe spp.

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Photo of a meloe blister beetle, female, on ground
Blister beetles in the genus Meloe are called oil beetles because of a yellowish oil they excrete from their joints when squeezed or distressed. This oil contains cantharidin, an irritating chemical that can cause blistering in many people.
Jim Rathert
Family

Meloidae (blister beetles) in the order Coleoptera (beetles)

Description

Blister beetles in the genus Meloe are called oil beetles because of a yellowish oil they excrete from their joints when squeezed or distressed. This oil contains cantharidin, an irritating chemical that can cause blistering in many people. Male oil beetles have weird kinks in their antennae for clasping the females during courtship. There are more than 20 Meloe species in North America, and all look rather similar: black, chubby, lacking hind wings, and with very short, overlapping wing covers. Learn more about oil beetles and other blister beetles (family Meloidae) in their family page.