its on my spring list, especially since my grandkids want to see Kelso Dunes.

those are nice pictures in what looks like Astragalus lentiginosus var. borreganus. Do you use a flash with your camera?
It was rather windy that afternoon, and on subsequent days the crowd of 17 (Jepson botany workshop with Jim Andre & Tasha LaDoux) chased most of the insects away.
Did you stay at Granite Cove?
I have some other pictures, taken a bit north of the dunes, but have to search.
P.S. Just found, and added, a photo of the bee in flight.

"what looks like Astragalus lentiginosus var. borreganus"

This is Leslie Saul's study plant.

"Do you use a flash with your camera?"

No, I used a Sony DSC-H5 with more or less default settings with 12x zoom from about 4 feet.

"Did you stay at Granite Cove?"

I stayed at the Zzyzx field station

Your images may also be of Habropoda pallida, but I can't see the wing venational character that would confirm this

perhaps that camera might be a good extra to carry along - just looked at a review.
Leslie Saul's study about phoretic nest parasites is fascinating. I read it some time ago, also added references on a couple of Meloidae pages at the time; perhaps time to look at it again since I didn't remember the Astragalus.
Next time I'll try to get the wing venation as well.