Butterflies of Thailand, Malaysia & Borneo
Emerald Nawab
Polyura jalysus  FELDER & FELDER, 1867
subfamily - CHARAXINAE

Polyura jalysus, Ulu Gerok, West Malaysia  Adrian Hoskins
There are 24 species in the genus Polyura, most of which are found in the Oriental region, although one species posidonius is restricted to Tibet and west China; 6 or 7 are endemic to various islands, e.g. andrewsi from Christmas Island and caphontis from Fiji; and one, pyrrhus reaches Queensland in Australia.
7 species occur in Malaysia - athamas, delphis, eudamippus, hebe, jalysus, moori and schreiber.
The butterflies are characterised by their distinctive wing shape with twin tails on the hindwings, a feature strongly reminiscent of the African Charaxes. Most have dark brown uppersides with bands of dazzling creamy white which vary in size and shape from one species to another. In the case of jalysus the upperside bands are yellowish and particularly large, while those on the underside are a beautiful shade of pale emerald green.
Polyura jalysus is found in Myanmar, Thailand, Laos, Vietnam, peninsular Malaysia, Singapore, Sumatra, Sabah, Sarawak, Brunei and Kalimantan.
This species is found in forested areas at elevations between sea level and about 300 metres.
I have no data regarding jalysus, but the lifecycle is likely to be similar to that of other Polyura species. The eggs will be spherical, probably yellow in colour., and laid singly on the underside of leaves of the foodplants. The caterpillar when fully grown will be green, and probably marked with one or more pale dorsal bands. As with other Polyura species it will have a large head with a flat face, adorned with a crown of 4 impressive long horns. The foodplants are likely to be primarily members of the Fabaceae. The chrysalis will be green, probably streaked or marbled with white, and will have a plump, rounded and compressed abdomen. It will be attached by the cremaster to a twig or stem on or near the foodplant.
Adult behaviour
Males are scarcer than those of athamas, but can sometimes be seen imbibing moisture from damp sand, gravel, or road surfaces, often in the company of other Polyura species. When feeding they are almost oblivious of humans, but if deliberately disturbed they fly up to settle on tree foliage nearby, and return as soon as they sense danger has passed. The flight is very rapid and powerful.


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