Richard called me outside to come see a big beautiful new butterfly. I'll spare you the misidentifications and confusion...I was able to get a good photograph of it, and after looking into the books and online at BugGuide.net, I am sure it was the black-form female Eastern Tiger Swallowtail, Papilio glaucus. Some of the females are black or dark (and sometimes you can see the "shadows" of the tiger stripes) and some are male. One book says the males prefer to mate with yellow females, but the dark females are less subject to predation, so the population maintains both color forms. All the males are yellow. The pale "epaulets" on this female are actually part of her underlying tiger-stripes. Behaviorally, this butterfly acted like the male tiger swallowtails (strong rapid flight, alighting only briefly, always with wings spread, then flitting away) and not like the black swallowtails and pipevine swallowtails she superficially resembles.