There are two species below. Both make their homes in our lower desert. Do you know which one of these two species is toxic? (If you know a little about nature, there is a big clue staring at you.) It secretes an irritating substance, cantharidin, which is used medically as a topical skin irritant to remove warts. It can also release some of this awful chemical and blister your skin if you come into contact with it. This blister can hurt for days and leave a welt for over a week. This is chemical warfare at its finest. Find out which one is toxic on our San Andreas Fault Tour!