Some time ago, after going over Paul Hurd's key (CIS Vol.1, No.6), I made a folder in my computer file, based on the possibilty of this being Campsoscolia alcione (now Crioscolia a.). However, I wasn't certain whether the antenna was clavate, with the apical flagellar segments enlarged. Your note reminds me I had wanted to look at specimens at L.A. Nat. Hist. Museum.

would have the apical flagellomeres clavate (for Trielis). The females' antennae are pretty consistent throughout since they're much shorter than the males'.

The best key for your area is William MacKay's key to southwestern Scoliidae, Hurd's is out of date. I can email it to you if you'd like.

Yes, I'd appreciate it very much if you could e-mail that key to me.

Happy to help!

Thanks, George!

Thanks for the input! I tried to compare wing veination with an image on the cedarcreek site, but feel my images aren't sufficiently clear. The hairyness between abdominal segments in the cedarcreek image appears to be different, though there could be variations.
Where might I find more descriptive information?

great photos! i like how the ant is dwarfed my the giant scoliid

Could be Trielis pollenifera which has head, antennae, and 1st abdominal segment black. Also abdominal tergites black with yellow spots.