The three pictures at the top were taken by me at Bowen Ranch. Below is a picture of the adult of Sphinx caterpillar that I borrowed from the net.

I guess this is a kind of "Stink Bug" White Lined Sphinx Moth Larva
A desert version of the "Tomato Hornworm"
White Lined Sphinx Moth Larva
Another one, but lighter in colors

I once had one of these huge moths fly right to my face and with it's great proboscis it probed the in inside of my nose!
See a video of this great moth in flight