Swallowtail – papilio machaon,
is a butterfly of the family Papilionidae. The butterfly is also known as the common yellow swallowtail or simply the swallowtail (a common name applied to all members of the family, but this species was the first to be given the name). It is the type species of the genus Papilio.

This butterfly is present throughout the entire Palearctic region, ranging from Russia to China and Japan, (including the Himalayas and Taiwan), and across into Alaska, Canada, and the United States, and thus, is not restricted to the Old World, despite the common name.

The imago typically has yellow wings with black vein markings, and a wingspan of 65–86 millimetres (2.6–3.4 in). The hindwings of both sexes have a pair of protruding tails which give the butterfly its common name from the resemblance to the birds of the same name. Just below each tail is a red eye spot.

It can be distinguished from Papilio hospiton, which occurs sympatrically with it on Corsica and Sardinia, by the longer “tails” on the hindwings.[7] It can be told apart from the Algerian species Papilio saharae only by counting the segments on the antennae.