Cerocoma schaefferi

Blister beetle resting on a yarrow on the side of a road.

The male of this small beetle has very large and strange antennae. The female lays her eggs on a plant foraged by square-headed wasps which use prey (Ortoptera or Mantis) to feed their larvae. The tiny Cerocoma larva climbs on a feeding wasp. If it is a female of the right species, it will lead them directly to the nest. He will drop into a cell, kill the wasp larva and take advantage of the food at his disposal to go out as an adult in the spring.