Papilio helenus, the red Helen,[1][2] is a large swallowtail butterfly found in forests of southern India and parts of southeast Asia.

[1][2] Papilio helenus is rarely found in Sri Lanka, southern and north-east India, Nepal, Bhutan, Bangladesh, Myanmar, Thailand, Laos, Kampuchea, Vietnam, southern China (including Hainan, Guangdong province), Taiwan, southern Japan, South Korea, Ryukyu Islands, peninsular and eastern Malaysia, Brunei, Philippines, and Indonesia (Sumatra, Java, Bangka, Kalimantan, the Lesser Sunda Islands except Tanimbar).

Body brownish-black; collar, front of head and palpi white-spotted; tegulae white fringed; legs and antenna black.Papilio helenus is generally uncommon and slightly threatened ( in certain places) .

The egg is pale apricot-yellow in colour when freshly deposited, spherical in shape and has a slightly roughened exterior which looks like the skin of an orange when seen through a microscope.

The eggs are deposited singly on the tips of very young leaves and shoots in shady parts of thick jungle.

While inactive, mainly during daylight hours, the young larva lies along the midrib of the underside of the leaf.

Later on, when it is largely fully grown, it is greener and lies on the centre of the upperside of the leaf, on a stem or a twig.