Night Visitor

I was pumping gas at my local filling station when I saw something at my feet that looked unusual.  I bent down and picked it up and realized that it was a very-much-alive moth, rather large and unusual in its black and white coloration (or lack thereof).  My picture, under artificial light gave it a off white coloration, which is wrong. I should have kept it until the next day to get its correct color.

 I had seen this moth before but not in a long time and, look as I may, I couldn't find the species, so I turned to my son, Rob, who is a research specialist extraordinaire and he found it.  It is the Rustic Sphinx,  Manduca rustica, a moth native to Mexico, Central America, and the southern US.

I looked very long and hard at it to see if I could understand why the "sphinx" designation, but couldn't figure it out. 

The caterpillar is large, green, and intimidating with a tall menacing- looking horn on the hind end.  I'd hate to meet him one dark night under a street light.