I was pruning on Korean Hill and found several dozen of these guys on Ulmus parvifolia

These aren't exactly pretty, but they're interesting. I used to know what they were when I was younger. I'll figure it out tonight or tomorrow. They are one of those "gregarious species that appear in the summer.

Like schooling fish, they move together. It's fun to get their attention and then move your hand back and forth. Their synchronized response never fails to make me laugh