[1] Papilio machaon was named by Carl Linnaeus in the 10th edition of Systema Naturae in 1758, alongside nearly 200 other species of butterfly.

[2] There are 41 recognized subspecies, that include:[3] Papilio machaon gorganus is strongly migratory in Europe and may be found in almost all habitats.

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.

In Asia, it is reported as far south as Saudi Arabia, Oman, the high mountains of Yemen, Lebanon, Iran and Israel.

[10] It can be distinguished from Papilio hospiton, which occurs sympatrically with it on Corsica and Sardinia, by the longer "tails" on the hindwings.

The butterfly has a strong and fast flight, but frequently pauses to hover over flowering herbs and sip nectar.

It frequents alpine meadows and hillsides, and males are fond of 'hilltopping', congregating near summits to compete for passing females.

Unlike other swallowtails which specialise on Rutaceae, this species mostly feeds on plants of family Umbelliferae, females laying eggs singly.

Milk parsley (also known as marsh hog's fennel) is normally the only food plant used by the caterpillars of the British subspecies.

In the Maltese Islands, the caterpillar feeds on plants such as rue (Ruta chalepensis) in addition to Umbelliferae such as fennel.

The British subspecies P. m. brittanicus is less mobile than its European continental counterpart and stays within, or close by, its fenland habitat.

It has a defense against predators in the form of an osmeterium, which consists of retractable, fleshy projections behind its head that can release a foul smell if disturbed, which deters insects, but not birds.

Butterflies can be lured to lay eggs in a backyard garden by keeping plenty of caterpillar food plants in it.

Care must be taken with fennel as well as dill, though, because they will not eat hard, woody stems; they need to be fed the tender leaves.

Pupae should not be kept on an impermeable surface, since when they eclose a bit of liquid will be released, this means the butterfly would stay wet and might not be able to fly.