Thanks again, Aaron, for pointing out the similarities to Hartmut's Euodynerus wasp. It's so interesting that two such attractive and similar (to the naked eye) wasps both overlap in the same bioregion. Such wonderful diversity in the insect world!

Aaron, thank you so much for bringing Hartmut's wasp to my attention. It is amazingly similar, and as you say, they are both in the same habitat and both out late summer to fall. I do see differences, but they are male and female, so that is not surprising. Also I see that Doug Yanega says that these wasps are really variable.

Definitely a lead that I appreciate very much!

Size may be too large. I went back to my field book. I took five images before I wrote anything down and I see I had a question about the magnification I used. And, these guys are hard to measure. Let me revise BL to about 11 mm.

Thanks so much for your help and comments. Gene and I discussed size at breakfast. Four of The pictures are small images taken from rather far away, which is why I went with the 14 mm in the first place. Gene suggested the best way to handle would be to put the range 11-14 mm, which is what I have just done.

A beautiful species indeed. It is not E. hidalgo because the hind margin of tergum 2 is thick, not thin and translucent. I am leaning towards E. castigatus or E. auranus but characters are conflicting: the propodeal angle seems to have several teeth (as in E. castigatus, see Fig. B5.31 of the Vespid Atlas (1)) but the apical flagellomere is black (as in E. auranus, should be yellowish in E. castiagtus: Fig. C26.3). If you have additional images showing the front side of the antennae that might be helpful.

I have submitted the last two images I have, but am not too hopeful. I really appreciate your help in trying to ID this eumenid. It's my first male, to boot, which I did not realize. Again, thanks so much.