MORPHOLOGY

External characteristics

Male
Forewing length (mm): 53-56. Wingspan (mm): 94-99.
Forewings: Upperside dark brown with straight band of rounded pale yellow median spots from hind margin to apex, confluent from hind margin to vein 3 or 4; underside as Upperside, but basal half finely dusted with pale yellow scales and veins outlined in pale yellow. Hindwings crenulate, with strong spatulate tail at end of vein 4; upperside with well-developed pale yellow submarginal spots, orange at tornus (space 1b), crescentic at least in spaces 2-4, straight pale yellow band from halfway inner margin to outer half front margin; underside similarly designed, but basal quarter finely dusted by pale yellow scales, veins outlined in grayish color, submarginal spots more or less confluent, not only orange in space 1b but also in space 7, median spots indicated as a fine bluish line.

Female
Similar to male.

Subspecies and variation

Some variation in the intensity of the yellow color on the upperside and the width of the bands, partly individual, partly geographical; in the greater part of the distribution area (from NE India to Lombok and Borneo) a single subspecies (ssp. demolion) occurs, two other subspecies are recognised, one on Nias (ssp. energetes) and one on Palawan (ssp. delostenus).

Similar species

The species looks like a smaller edition of Papilio gigon, see there.

_{source: Jan Moonen, peronal communication 2020}