This family considered to be large with over 300 species. Most of these are in the western part of North America.
These beetles get their name from the “reflex bleeding” that occurs at their leg joints when they are disturbed. The liquid that oozes from them is the chemical cantharidin that causes blisters and lesions. This chemical is transferred from the male to the mated female and then on to the eggs to protect them; only unmated females would not have this. These beetles have pests that are associated with them, biting midges. Because of the cantharidin, it’s assumed these midges derive some protective benefit from lapping up the beetles’ blood after they bite them.
Their eggs are white to orange and cylindrical in shape. They lay their eggs in masses that range from a few to thousands in the soil.