Probable Hyles lineata
Thought you’d enjoy this image. I was in a isolated part of Baja California (about 200 mi south of the border, near the ocean), and there was a massive flight of sphinx moths. They all converged on this one agave (Agave shawii). There must have been 50 – 100 moths flying around. This image was taken just at sunset, and you can see the orange light reflected off the bug’s legs. Let me know if you want other more identifiable images.
We have gotten reports large numbers of Striped Morning Sphinxes in the desert in the past. The caterpillars are also often found in great numbers eating desert plants in the brief periods of time they are green.