A Monstrous Caterpillar

This caterpillar is about 3 inches long - quite impressive! It's a Pandora Sphinx moth caterpillar, a North American native. This one is feeding on one of its favorite vines - Virginia Creeper, which I'm pleased to have in my yard. 

The caterpillars live through 5 different stages, beginning with a green phase. This one is likely in the last stage, since the characteristic horn at its rear is no longer present, a developmental indicator.

If you look closely at the next pic, you can see that the front end looks like mostly mouthparts with 6 small true legs that are holding the foliage as it feeds.