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.
Comma list of more than two elements. A comma used in such a position is variously called a serial comma, an Oxford comma, or a Harvard comma (after the Oxford University Press and Harvard University Press, both prominent advocates of this style). Such use of a comma sometimes prevents ambiguity: The serial comma does not eliminate all confusion. Consider the following sentence: As a rule of thumb, "The Guardian Style Guide" suggests that straightforward lists ("he ate ham, eggs and chips") do not need a comma before the final "and", but sometimes it can help the reader ("he ate cereal, kippers,