This is a black walnut tree. My brother noticed them while we were in the backyard. I have other trees that are not black walnut and do not see these bugs on them.
They are red with a black head. Their bodies have ridges on them. It's hard to tell because they are so small. Closer to a large grain of salt, or small piece of rice.
Update: This is from Northeastern Oklahoma area. They have since disappeared. I'm not sure if the heat got to them or they turned into something else or what.