I have more pictures if they might be helpful for IDing the wasp--I'm also curious about the caterpillar, if anyone can tell what it is.

Also, if behavior is relevant (as the page for Podalonia suggests), we watched the wasp excavate the nest, the wasp flew away, the wasp came back with the caterpillar, put it in the nest, and backfilled. However, she wasn't gone long, so maybe she'd cached prey hunted earlier, as some of the papers cited on the genus page describe.