Parasitic wasps can be either friend or foe. The long black "stinger" on the back end of its body is an ovipositer — a device that allows it to lay eggs in the soft larval body of a variety of insects, including beetles, grubs, flies and pest caterpillars. Its young hatch inside the host's body and eat their way out. The catch is that sometimes it preys on beneficial insects and spiders, such as butterflies and other wasps. Some species lay their eggs in wood.
There are thousands of species in a variety of shapes, colors and sizes, and they're found throughout the U.S. Parasitic wasps typically look like skinny wasps with very long antennae. You can usually find them hunting in the garden for prey by day or flying around porch lights in the evening. The adults of most types can sting.