Thank you for sending the image with your question. Your identification is accurate. The insect is Hyles lineata, the whitelined spinx. It’s one of several kinds of moths in the Sphingidae family referred to as “hummingbird moths.” These moths are occasional visitors to our northwest gardens but seldom damage them.
“Larvae develop on a variety of plants but seldom do they significantly damage those plants considered economically important. Portulaca, primrose, and wild grape are among the most common larval hosts.” (Hornworms and “Hummingbird” Moths: http://www.ext.colostate.edu/pubs/insect/05517.html) Also see: http://pnwmoths.biol.wwu.edu/browse/family-sphingidae/subfamily-macroglossinae/hyles/hyles-lineata/
Thank you for the very fast response.