Tarantula hawk

Pepsis spp. At Calico Ghost Town, California. These wasps get their name because they sting a tarantula and lay an egg on the paralyzed spider. The larva, on hatching, then feeds on the still-living spider. They're also supposed to have one of the most painful stings of any insect--I don't even want to _think_ about how that information was gleaned! ;) The wasp is otherwise not aggressive, however. Presumably it's focused on finding a tarantula.