Blister Beetles-Meloidae

The slender Coleoptera of the family Meloidae are commonly called blister beetles. Members of most species, particularly Cantharis vesicatoria, the so-called Spanish fly, contain a substance known as cantharidin. This is a poison that causes blistering, inflammation, and ulceration of the skin and mucous membranes. Swallowed, it irritates the bladder, harms the kidneys, and stimulates the sex organs. It can also cause delirium and death. Cantharides was used as an aphrodisiac and medicine from the days of ancient Greece until about 1900, when it finally became apparent that the dangers outweighed the benefits.

Blister beetle larvae feed on grasshopper eggs and bee eggs, and some species live in beehives. The blister beetle undergoes a hypermetamorphosis-a large number of distinct larval stages. During the first larval stage the insect is known as a triungulin. In the species that inhabit beehives, a triungulin climbs on flowers. When a bee visits the flower, the triungulin hooks onto its legs or underside so it will be carried to the bee's hive. When triungulins mistakenly hook themselves to insects other than bees, the error is almost always fatal.

Blister beetles of the genus Nemognatha display long sucking tubes, sometimes longer than the beetle itself, with which they draw nectar from flowers. Blister beetles of the genus Meloe, found in the southwestern United States, are known as "oilbeetles" because of the yellow, oily fluid they secrete when disturbed.