Swallowtail butterfly black swallowtail is the state butterfly of Oklahoma. Swallowtail butterfly Swallowtail butterflies are large, colorful butterflies in the family Papilionidae, and include over 550 species. Though the majority are tropical, members of the family inhabit every continent except Antarctica. The family includes the largest butterflies in the world, the birdwing butterflies of the genus "Ornithoptera". Swallowtails have a number of distinctive features; for example, the papilionid caterpillar bears a repugnatorial organ called the osmeterium on its prothorax. The osmeterium normally remains hidden, but when threatened, the larva turns it outward through a transverse dorsal groove by inflating it with fluid.
Swallowtail butterfly species inhabit altitudes ranging from sea level to high mountains, as in the case of most species of "Parnassius". The majority of swallowtail species and the greatest diversity are found in the tropics and subtropical regions between 20°N and 20°S, particularly Southeast Asia, and between 20°N and 40°N in East Asia. Only 12 species are found in Europe and only one species, "Papilio machaon" is found in the British Isles. North America has 40 species, including several tropical species and "Parnassius". The northernmost swallowtail is the Siberian Apollo ("Parnassius arcticus"), found in the Arctic Circle in northeastern Yakutia, at altitudes