Oil beetle Meaning, Definition & Usage

  1. noun any of various beetles that exude an oily substance from the leg joints that deters enemies

WordNet

Definitions
  1. (Zoöl.), any beetle of the genus Meloe and allied genera. When disturbed they emit from the joints of the legs a yellowish oily liquor. Some species possess vesicating properties, and are used instead of cantharides.

Webster 1913