This is a Mydas fly, likely
Mydas tibialis. It is on a plant called rattlesnake master (
Eryngium yuccifolium). One of my favorite plants. It seems to attract a number of insects including the various Hymenoptera in the picture.
These flies aren't commonly found, but I have seen this and one other species in the last 10 or 15 years. My observation of the other species, Mydas clavatus, was of three individuals resting on a concrete curb of a loading dock of a building on about 200 acres of mixed woods and on a bluff overlooking the Missouri River bottom.
Many of the species are very large and the family includes the species that is the largest fly,
Gauromydas heros. A giant that reaches 60 mm.
When I was a kid, I had these little nature books my folks gave me. In it was a picture of
Mydas clavatus. I really wanted to find one and I spent time looking for it. As time passed, other things pushed that out of my mind and I sort of gave up on the idea. Then one day without even trying, there they were, three in a row. I knew immediately what they were. There was no chance to catch one and I didn't have a camera on me. This was before smart phones. Having missed that one, I couldn't believe my luck years later to chance upon another species and with a camera on hand too.
