Graphium agamemnon, the tailed jay,[2][1] is a predominantly green and black tropical butterfly that belongs to the swallowtail family.

[2][1] Southern India to Saurashtra, northern India (Kumaon to Assam), Nepal, Sri Lanka, Andamans, Nicobars, Bangladesh, Brunei, Myanmar, Thailand, Laos, Cambodia, Indonesia, Vietnam, Singapore, southern China (including Hainan), Taiwan, Japan (Ryukyu Islands), South East Asia to New Guinea, Bougainville, Solomon Islands, and Australia (northern Queensland).

[3] Race decoratus is found in the Andaman and Nicobar islands and is very similar to the typical form, from which it can be distinguished as follows: Upperside green spots smaller, especially the discal series on the forewing.

Once found primarily close to wooded country where there is a fairly heavy rainfall, the tailed jay is now very common at low elevations and regularly seen in gardens and urban areas due to its food plant, Polyalthia longifolia (false ashoka or mast tree), being widely used as an ornamental tree.

Tailed jays are active throughout the year but their abundance depends upon the local monsoon and availability of the larval host plants.

The butterflies generally fly among the tree-tops but descend to ground level in search of flowers or host plants.

Because of their relatively fast life cycle (just over one month from egg to adult), tailed jays are multivoltine and may produce up to seven or eight broods per year.

The color is at first smoky black, but at the last molt becomes a light clear green faintly marked with lines of a darker shade.