This is a common southern US swallowtail that many other butterflies mimic.  The caterpillars of this species eats noxious pipevines and those toxins are passed on to the adult stage.  The adult stage is black with a blue-green iridescence on the upper wing.  Some of the mimics include the black form of the female Eastern Tiger Swallowtail, (Papilio glaucus), the Red-Spotted Purple, (Limenitis arthemis astyanax), the female Diana, (Speyeria diana), the Spicebush Swallowtail, (Papilio troilus), and the Black Swallowtail, (Papilio polyxenes).