Lytta vesicatoria, commonly known as the blister beetle, is a species of insect belonging to the family Meloidae. These beetles are typically elongated and have a soft body covered in a protective exoskeleton. They are known for their defensive mechanism of releasing a toxic substance called cantharidin, which can cause blistering and irritation on human skin upon contact. Blister beetles are often found in fields and gardens, feeding on plants and occasionally on other insects.