''Papilio elwesi'' is a

butterfly Butterflies are insects in the macrolepidopteran clade Rhopalocera from the Order (biology), order Lepidoptera, which also includes moths. Adult butterflies have large, often brightly coloured wings, and conspicuous, fluttering flight. The ...

of the family

Papilionidae 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 larges ...

. The species is endemic to

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

and

Vietnam Vietnam or Viet Nam ( vi, Việt Nam, ), officially the Socialist Republic of Vietnam,., group="n" is a country in Southeast Asia, at the eastern edge of mainland Southeast Asia, with an area of and population of 96 million, making i ...

. ''Papilio elwesi'' (along with '' P. maraho'') differs from all other ''

Papilio ''Papilio'' is a genus in the swallowtail butterfly family, Papilionidae, as well as the only representative of the tribe Papilionini. The word ''papilio'' is Latin for butterfly. It includes the common yellow swallowtail (''Papilio machaon''), ...

'' species in the tail of the hindwing being so dilated that two veins are necessary to support it. Together these two species form the subgenus ''Agehana''. The larvae feed on

Lauraceae Lauraceae, or the laurels, is a plant family that includes the true laurel and its closest relatives. This family comprises about 2850 known species in about 45 genera worldwide (Christenhusz & Byng 2016 ). They are dicotyledons, and occur ma ...

species.

Etymology

It is named for British botanist, entomologist, author, lepidopterist, collector and traveller,

Henry John Elwes Henry John Elwes, FRS (16 May 1846 – 26 November 1922) was a British botanist, entomologist, author, lepidopterist, collector and traveller who became renowned for collecting specimens of lilies during trips to the Himalaya and Korea. He wa ...

. elwesi Butterflies of Indochina Butterflies described in 1889 {{Papilionidae-stub