I think this may be a Black Swallowtail, but the double row of spots on the dorsal side of the wings is missing, and the pattern of orange spots on the ventral side is different than usual. I see a lot of what may be Black Swallowtails now, but there seems to be a lot of variation. Some individuals have only black and yellow markings, and many of the newer Black Swallowtails seem diminished in size (would a drought, which we have, do that sort of thing?).