Blister Beetle, common name for any member of a family of beetles, so called because of the caustic chemical cantharadin that they contain, which can raise blisters on human skin. Typically, blister beetles are cylindrically shaped, although a few have spherical bodies. The thorax is narrower than the head.
The insects of this family pass through a complex metamorphosis, some having as many as nine distinct stages from egg to adult. The early-stage larvae are fast-moving parasites of other insects, while later-stage larvae are parasitic but sedentary. Hosts include wild bee larvae and the buried egg masses of grasshoppers. The adult beetles are vegetarian and some are minor pests of crops. For example, the striped blister beetle, with black and orange stripes and the margined blister beetle, black with gray margins, are what many people think of as old-fashioned potato beetles. The Spanishfly is another species of blister beetle, famous for the aphrodisiac qualities of its extract. Another group of species are known as oil beetles because they secrete an oily substance from their joints when disturbed.
Scientific classification: Blister beetles make up the family Meloidae, order Coleoptera. The striped blister beetle is classified as Epicauta vittata, the margined blister beetle is E. pestifera, and the Spanishfly is Lytta vesicatoria. Oil beetles make up the genus Meloe.