In North America there are 206 species. Most are black in color, although some may also have some red, white, or yellow portions or may have a blue or green tinge. They are usually solitary and ground nesters. Adults eat nectar from flowers like this one is doing.
For propagating the thread-waisted wasp will paralyze an insect, typically a caterpillar or a grasshopper, or spider depending on the type of wasp, with its sting and then carry it to a ground nest. It will then lay an egg in the immobilized prey and cover the nest. When the larva hatches it will use the host as a food source and then pupate underground.