If It Isn't Moths, It's Caterpillars

It's a good thing I'm fascinated with insects and don't find most of them to be icky or creepy. I'll get up close and personal with most of them.  Last week, it was the Imperial Moth.  This week it's these guys, although I did keep them at arm's length because of the sheer number of them:

All those caterpillars are on ONE oak leaf.  We cut the end of the branch from our neighbor's tree that hangs over our property and burned it.  He had told us last year that we could cut the tree back if we wanted to, because it was getting close to hitting our house.  We were looking at that situation this evening when we noticed the caterpillars.

They're skeletonizing the leaves, leaving a lacy framework that's pretty incredible.  The leaf veins are intact and the result is a work of art.  The caterpillars aren't likely to harm the large oak tree, but they're hanging directly over our shade garden and we don't want them to move on to any of our smaller trees or plants.  Those might not survive.

I'm thinking these are the larva of the Hickory Tussock Moth, but I'm not positive.  They don't form "tents," and they do drop down on a strand of silk if disturbed.  We've lived here for nearly 33 years and this is the first time we've ever noticed these.

Do you have any thoughts to share about these fuzzy fellows?