When I think of beetles, what comes to mind are ladybugs, ground beetles, fireflies...maybe stag beetles. All of these are terrestrial beetles and are pretty neat, but why stop at land? There are a number of aquatic beetles that are just as cool, and can be found in rivers, streams, and standing water. I was canvasing my yard the other day when I came upon a wheelbarrow that was full of standing water. I've checked it a few times before for insects, but usually only find mosquito larvae. Last summer I did find one aquatic beetle, but I never got around to investigating what it was. When I checked it this time, however, I found a much more diverse assemblage of creatures. Acilius mediatus The orange you see in that picture is rust, while the green gelatinous stuff is an egg covering from one of the species of aquatic beetles in the wheelbarrow. Either that or it's algae or something similar. The beetle Acilius mediatus is in the family Dytiscidae, the predacious diving bee...