Swallowtail butterfly 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. The forked appearance of the swallowtails' hindwings, which
Serial comma "against" consistent use of the serial comma: Many sources are against both systematic use and systematic avoidance of the serial comma, making recommendations in a more nuanced way (see Usage and subsequent sections). The style that always uses the serial comma may be less likely to result in ambiguity. Consider this apocryphal book dedication: There is ambiguity about the writer's parentage, because "Ayn Rand and God" can be read as in apposition to "my parents", leading the reader to believe that the writer claims Ayn Rand and God are the parents. A comma before "and" removes the ambiguity: But lists