Teinopalpus imperialis, the Kaiser-i-Hind, is a rare species of swallowtail butterfly found from Nepal and north India east to north Vietnam. The common name literally means "emperor of India". The Kaiser-i-Hind is much sought after by butterfly collectors for its beauty and rarity. The green iridiscence of the wings has been found to be due to three-dimensional photonic structure of the scales and is the subject of much research.