The Lime Swallowtail Butterfly, also called the Common Lime, the Citrus and the Chequered Swallowtail is native to Asia, covering the Middle East, South and Southeast Asia and Australasia.
A strong flier and coloniser, it has also spread to the Caribbean and Central America. Its caterpillars feed on citrus, especially limes.
Male and female look similar; females are usually larger. Individual patterns vary. One of the swallowtail family with a wingspan of up to 100mm, neither male nor female have a swallow tail.
(A similar-looking and related species with a tail is the Madagascan Emperor, P. morondavana; similar species P. erithonoides also in Madagascar is without tails.)
The white yellows with age. A lot of activity/flying in forest areas can also lead to tattered individuals.
The underside has coloured red, light brown/yellow ochre and pale blue markings on a pale (white or pale yellow) background,
- the underside, particularly the pale background, being the key difference between the otherwise similar African Citrus Swallowtail, P. demodocus (see link below).
Although the topsides of the Asian and the African Lime/Citrus swallowtails look very similar, there are subtle differences in addition to the obvious pale vs dark underside (see link below). The red "eye-spot" or "tornal spot" differs: the round "pupil" in the Asian
(demoleus) is black with a blue "eyebrow"; the "pupil" is blue in the African (demodocus) with a black under curve.