These wasps have thread-like waists and very long antennae. They vary greatly in color from red and orange to many shades of brown and some have stripes and some not. There are over 3,300 known species in North America alone.
The larvae take up residence in caterpillars and sometimes spiders. The larvae then develops inside the host feeding on it and killing it.
Adults drink nectar and water, so to encourage them to stay, plant umbrella-shaped flowers such as tansy and lovage. They also prefer higher humidity. They range in size from 1/8 inch to 1 5/8 inch.