Spanishfly is a type of blister beetle, not a true fly. Spanishflies are found throughout Europe. They are about 3/4 inch (19 millimeters) long and often are metallic-green or bronze in color. A dangerous chemical called cantharidin can be extracted from their bodies. It is used as a vesicant (blistering agent) and as a skin irritant. When taken internally, cantharidin may increase a person’s blood circulation.
