I thought at first this was the tobacco hornworm, but the stripe color and spiky tail and head are a little different. Plus, it's eating Cardinal Climber (
Ipomoea), not one of the usual hosts. Now I think it must be Rustic Sphinx, which does host on Convolvulaceae. There are not many pictures on the internet, though I found
this one at Moths of Arizona that matches. Does anyone have a book with this in, to confirm? J & J?