The Scoliid Wasp, Scolia dubia, is a natural control of the imported Japanese Beetles and others. They burrow through infested lawns searching for grubs to inject eggs into. They rarely if ever sting too. So they're an over all beneficial wasp and pretty to look at from the right angle.
When not seeking out grubs adults gorge on nectar from lots of different plants. Usually ones with lots of tiny flowers such as Goldenrod, Clethra alnifolia, and Sedum. As with many solitary bees though they're only active for a short while; in this case about August to September so keep your eye open.
I want to say I've seen other species around though. One was a much smaller wasp but the abdomen had to be twice as long as the rest of the body. Which was funny to see.