At a barbeque just east of Casper last night, we were watching the behavior of literally millions of small bugs and their swarming activity. As near as I could tell these bugs were Mayflies and the oddity was that they would swarm in a column that would rise straight up from a post, a tree branch or above a vehicle. I can only guess that this is common behavior as we saw this replayed above every object around the property. After a bit of research on line there are a couple of articles that address this action, but I couldn't find any images that matched with the picture that I took. Has anyone else seen this type of swarming? Or do you have a better explanation for what I saw.