These huge wasps (the largest wasps in the United States - up to two inches long) feed on nectar, but procreate in a particularly morbid fashion (the basis for their name). When a female is ready to lay her eggs, she seeks out a tarantula and injects it with paralyzing venom. She drags the tarantula to a burrow and stuffs it down the hole, then lays her eggs on top of the paralyzed spider. Several days later the eggs hatch and the larvae feed on the still living tarantula.
Several species of wasps known as "tarantula hawks" inhabit the deserts of the southwest that build nests in the ground and provide their young with spiders for food (Pepsis formosa and Pepsis thisbe are probably the two most common). The majority of these wasps have metallic blue bodies with fiery red or orange wings, and long legs ending in hooked claws.
Tarantula hawk stings are considered to be one of the most painful insect stings in the world (the stinger of a female tarantula hawk can be up to 1/3 inch long).