Papilio helenus is a large swallowtail butterfly found in parts of S.E. Asia, and the forested parts of southern India. (They are endemic in Assam and Western Ghats.)
   Their preferred terrain is rainforests with an altitude of up to 1800 m above sea level.
   They are on wing throughout the year in Southern India, and from May through September in the rest of their range.
   They are powerful flyers that can be seen flying along forest trails with deep, irregular flapping.
  Male butterflies are usually found alone or with two or three others visiting puddles, while the females are looking for a place to lay eggs or hovering in the flowering bush.
   They are usually at rest with their wings fully extended.
   Papilio helenus has black colored wings, and on the dorsal side of the wing there is a large white spot on the hindwing which is hidden when the butterfly is resting but stands out when flying.
   There is an additional dusty white stripe on the forewings, while on the hind wings there is a row of red crescent shaped markings on the sub-margins of the hindwings.
   The appearance of the ventral side of the wings is the same as that of the top.
   Potential predators include birds, spiders, praying mantises.