| Fly blister
A cantharidal blister caused by discharge of a vesicating body fluid by certain beetles, particularly members of the family Meloidae that produce cantharidin, Lytta (Cantharis) vesicatoria, the notorious “Spanish fly;” noncantharidin vesicating fluid is produced by other beetles, such as rove beetles (family Staphylinidae), especially the genus Paederus, whose fluid, on contact with the skin, produces an intensely painful blister. | |