Not really a moth actually, but the caterpillar of a moth.
This fat fellow in the hairy jersey is the larva of the Buff Tip moth. I found this one crawling over the yard, probably looking for a suitable bit of earth in which to pupate.
The caterpillars feed in colonies and can often strip every leaf from a branch of their favourite trees. They're particularly partial to oak, birch and sallow, but will eat almost any leaves if need be. The adult moth will emerge next June, but they are rarely seen except when attracted to a light.