Nice shots, Deb! I haven't seen one of those yet, this year! Kind of jealous. We had one in the garden last year, that I stalked with a big lens.

The way the fly is fascinating to watch, too. Butterflies in general seem to be completely incapable of flying in any kind of straight line and, yet, they still seem to manage to land right on target. Is that a sweet rocket that your swallowtail is landed on?