The only one I can come up with is Tersa moth. But it's a bit different than the pictures I have found.

You are likely correct. Note the variations here:

https://bugguide.net/node/view/419/bgimage

(select caterpillars in the Show images of line if the webpage comes up otherwise)

Iris, great pic. I think it is a tersa sphinx moth. They like pentas and hamelias and are very variable in color. Here's a link to one of my posts from a while back to see some examples of color.

http://forums.gardenweb.com/discussions/3459077/is-this-a-sphinx-moth-cat?n=8

Thank you, The Logician and Rhonda. Most of my Pentas had a bad year. The deer kept them pruned at about 4 inches. We had our first frost the day before Halloween, so I took a few cuttings inside to try if they would root for next Spring. I was very surprised to find the caterpillar in my kitchen. It might freeze again tomorrow night. I hope I can protect the caterpillar and his plant from it. He was happily eating earlier. Last time just the outer layer of the plants froze off. Same with the lantana, the Zinnias are gone. The popcorn Cassia I got from your seeds doesn't show any sign of damage and even has seed pots!

Have to add the pictures in your post are a lot better.