In the late summer these very large, black wasps with wings that shimmer blue in the sunlight, begin to appear. They are Great Black Wasps. They are part of a group referred to as thread-waisted wasps because of the narrow constriction between abdomen and thorax. There is little to fear from them. They are solitary, with no nest to defend. The female will dig a hole (thus, they are also called Digger Wasps), she will then drop a freshly killed grasshopper or katydid into the hole, lay an egg, top off with 2 more tasty morsels, cover, and leave. These wasps are important in insect control.