A worldwide community photographing and learning about wildlife
Project Noah Nature School
That is, the wasp is surely Palmodes praestans. See
http://bugguide.net/node/view/1327587
I observed just such a wasp dragging a sooty longwing across sandy soil in the Sandia Mountains of NM. I collected, imaged, identified, and posted the images on Bugguide at the referenced link. It appears to be a rather uncommon species of wasp, based on the references cited therein.
