Flipped over a piece of log on a big dead stump and there were tons of those little iridescent blue-purple springtails, but also several mesostigs. I was watching them hoping one would catch a springtail, and one seemed to be questing about for something. Then it chased after one of the other mites, flung itself on its back, and after some tumbling around ended up clinging to its underside. Then, this. I'm not even sure what's happening, I don't even know what appendages these mites use for sperm transfer.
edit: oh yeah I forgot to add they're totally having sex