Blister beetles secrete cantharidin,a powerful vesicant.Crushing a blister beetle between the fingers results in severe blistering of the skin.When horses eat hay containing blister beetles,they often die from The vinegaroon(whip-tail scorpion) gastroenteritis and kidney failure CH expels a defensive spray consisting of 84%acetic acid,5%octanoic acid. caused by cantharidin poisoning. and 11%water.Octanoic acid acts as a wetting and spreading agent. 斑蝥素 CH3O cantharidin 斑蝥素