Graphium agamemnon, the tailed jay, is a predominantly green and black tropical butterfly that belongs to the swallowtail family. The butterfly is also called the green-spotted triangle, tailed green jay, or green triangle. It is a common, non-threatened species native to Nepal, India, Sri Lanka through Southeast Asia and Australia. Several geographic races are recognized. The species was first described by Carl Linnaeus in his 1758 10th edition of Systema Naturae.

In the 10th edition of Systema Naturae, Carl Linnaeus classified the arthropods, including insects, arachnids and crustaceans, among his class "Insecta". Butterflies and moths were brought together under the name Lepidoptera. Linnaeus divided the group into three genera – Papilio, Sphinx and Phalaena. The first two, together with the seven subdivisions of the third, are now used as the basis for nine superfamily names: Papilionoidea, Sphingoidea, Bombycoidea, Noctuoidea, Geometroidea, Tortricoidea, Pyraloidea, Tineoidea and Alucitoidea.