Papilio polyxenes, the (eastern) black swallowtail, American swallowtail or parsnip swallowtail, is a butterfly found throughout much of North America. It is the state butterfly of Oklahoma and New Jersey. 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. The species is named after the figure in Greek mythology, Polyxena (pron.: /pəˈlɪksɨnə/; Greek: Πολυξένη), who was the youngest daughter of King Priam of Troy. Its caterpillar is called the parsley worm because the caterpillar feeds on parsley.