The first time one whizzed by my head, I was certain it was a bee. Then I saw it hovering by the purple thistle and I wasn't quite sure what the heck it was. It looked like the love child of a butterfly and a hummingbird. A quick search of google later, and I knew I was dealing with a hummingbird moth, Hemaris sp. It does seem to have antennae more befitting a moth than a butterfly. I believe there were two of them in the field that day but I have never seen even one of them before. I hope to see them again in the future.