The Papilio zelicaon, commonly known as the Zelicaon Swallowtail, is a butterfly species in the family Papilionidae, found primarily in western North America. It is notable for its large size and distinctive appearance, with bright greenish-yellow and black wings that feature prominent patterns. The hindwings are tail-like, typical of swallowtails. This butterfly inhabits open woodlands, grasslands, and areas with abundant wildflowers, where it feeds on nectar. The larvae primarily feed on plants from the Rutaceae family, such as orange and ash trees. The Papilio zelicaon is an important pollinator and plays a role in local ecosystems.