The Spanish fly is an emeral-green beetle in the family Meloidae, Lytta vesicatoria. It is 15 mm to 22 mm long and 5 mm to 8 mm wide, and lives on plants in the families Caprifoliaceae and Oleaceae. The beetle contains up to 5% cantharidin which irritates animal tissues. The crushed powder of Spanish fly is of yellowish brown to brown-olive color with iridescent reflections, of disagreeable scent and bitter flavor.