for the ID, Bob.

Is it known what the typical prey is for this species (or genus)? The Subfamily Crabroninae info page states, "Prey is mostly flies, but some utilize other insects." The remarks for the photo you linked state, "grasshoppers/katydids(?)."

I have now checked "female" for these photos.

Thanks for labeling her sex, because that will help other people! OK, I have not seen this species with prey yet. I know that some of the Square-headed subfamily prefer to prey on Katydids or Grasshoppers or both. Sometimes this may depend on what is more abundantly available in certain areas, since this is a widely distributed genus. The subfamily itself is very large and I'm still learning about them. Here's another species in this genus, from Florida:
♀ There's one example anyway.
Eric Eaton has more info about this on his BLOG. Here is a link for you: Bug Eric: Green-eyed Wasps, Tachytes
For your information, your wasp's species is one of the easier IDs of this genus and she fits all of the qualities listed by Dr. Buck and more:
1) - female with two stripes on abdomen = pass
2) - no silvery pubescence on scutellum = pass
3) - half of wings golden & half darkened = pass
4) - legs very dark overall with completely black femora = pass
5) - eyes dark green with darker edges = pass

for the detailed ID info and the link to Eric's blog article, Bob. Eric states that all North American Tachytes spp provision with Acrididae, Tetrigidae, Tettigoniidae or Tridactylidae, so "grasshoppers/katydids" looks right.

Based on your list of ID characteristics, I am going to move to species (editors: feel free to move it back, or anywhere else, if that is preferable).