I'm only an amateur entomologist, and I only really know anything about identifying bugs that have some significant relationship to my lawn and garden. I have grown tomatoes before, and it looks like that caterpillar has the curled-up leaf camouflage of a "horntail" -- a true tomato connoisseur. However, I don't see the characteristic (and eponymous) member on the creature the photo, so that kinda shoots down that theory. Any idea what plant it was browsing on? Horntails like plants in the solanaceae (nightshade) family: tomatoes, potatoes, tobacco, eggplant, peppers, jimson weed etc. etc. . . . and of course nightshade.

ed. because spelling is hard