At first glance, you might think this little insect is a type of wasp. But look at those stubby antennae (coming out from the center of the head) and the fact that it only has one pair of wings. The Thick-headed Fly is a great wasp mimic and can be found in the western half of the U.S. and Canada. They are parasites of wasps and bees, especially the American Bumblebee (Bombus pensylvanicus).
Photo by: Glenn Marangelo on 7/6/21 near Florence, MT