Have a whole colony of them huddled up on my oak tree.

I've done some different image searches and can't find anything close. Can you get a picture of one up close so we can see the legs, antennae, color etc a little better? A few of them seem to have some lighter-colored bands on their abdomens.

That big group like that also makes me think they're a nymph stage and so it may be harder to tell what they aremost Internet photos seem to be adult stage.

Bark lice. Solved.

You ever watched "The Mummy"?

Here is a TAMU Ag Extension link

Bark Lice