Aptly named, gnat-ogres are miniature robber flies, and every bit as carnivorous as their larger, more visible brethren. You've just got to look closely to see them. The gnat-ogre pictured above would be measured in millimeters. They are so small that a person would likely dismiss them as gnats or perhaps extremely tiny flower flies. With the naked eye, they are scarcely visible unless one happens to be closely studying the area in which gnat-ogres have staked out. To get these photos, I was using a heavy-duty macro lens, flash, and a tripod. Fortunately, gnat-ogres are fearless and will allow very close approach.
Ohio naturalist Jim McCormac describes them as "neat," so that's good enough for me! Link -Thanks, Manticore!