The (eastern) black swallowtail (Papilio polyxenes), also called the American swallowtail or parsnip swallowtail, is a butterfly found throughout much of North America. It is the state butterfly of Oklahoma. An extremely similar-appearing species, Papilio joanae occurs in the Ozark Mountains region, but it appears to be closely related to Papilio machaon, rather than P. polyxenes.
Read more about Papilio Polyxenes: Description, Caterpillar and Chrysalis, Similar Species, Photogallery