MORPHOLOGY
External characteristics
Male
Forewing length (mm): 45-49. Wingspan (mm): 76-84.
Forewings: Unmarked dark brown or with paler to brownish white smudges between the veins in the submarginal area, broadening towards apex; underside similar. Hindwings smoothly rounded, slightly paler brown than forewing, double whitish internervular smudges (which may be almost indiscernible), orange-yellow dot at tornus; underside similar.
Female Wingspan (mm):up to 94.
Larger than male but for the rest, similar to male.
Subspecies and variation
The variation as described above, is mainly geographical; four subspecies have been distinguished, two of which occur in the Malesian area: ssp. perses in Sumatra and W Malaysia, ssp. hewitsoni in N Borneo.
Similar species
Superficial similarity with species of the poisonous genus Euploea (Danainae, Nymphalidae), but in addition to the presence of a single anal vein in the hindwing instead of two, the yellow-orange spot at the tornus of the hondwing easily sets this species apart.
source: Jan Moonen, peronal communication 2020