Lateral view, showing the all-dark abdomen, which is one easy way to separate from the somewhat similar Great Golden Digger Wasp, Sphex ichneumoneus--that one has an orange-and-black abdomen, I believe. Also, the pubescence on that species is, well, golden, and not silver:

(This is rather a difficult genus, and I want to be sure that I'm identifying this wasp and its relatives correctly.)