The scoliid wasps: natural enemies of Japanese beetles

In a previous post, I had a question about the identification of a wasp my son had photographed.  I spent a little time looking for it.  I found something called a blue-winged wasp (scolia dubia) that seemed close (except for the color of the abdomen).  I became interested in the blue-winged wasp when I found out it is a natural predator of Japanese beetle grubs.  Good news there! 
My older sister tracked down the answer to our mystery insect.  The critter we had seen was a double-banded scoliid (scolia bicincta).
I thought I had seen some blue-winged wasps on my hoary mountain mint.  I went out with my camera, and, sure enough, there were both scolia dubia and scolia bicincta on my mint.  Here are some pics from this afternoon.