prexaspes is a migrant from Malaysia and has recently begun to colonise
certain areas in the Singapore forest reserves. It was not recorded by
the researchers who studied the biodiversity of Singapore's butterflies
in the 60's and 70's.
This butterfly is one of the
"Swallowtail" species. The species has a wingspan of about 100-110mm and
has a white patch on the hindwing.
There are blue lunules along
the hindwing margins. It feeds on roadside flowers like the Common Asystasia
and Lantana. Both these specimens, males, were photographed feeding at
roadside seepages and rotting carrion in the nature reserves.