Chrysiridia rhipheus, the Madagascan sunset moth or simply sunset moth, is a day-flying moth of the Uraniidae family. It is considered to be one of the most impressive and beautiful Lepidoptera, though the iridescent parts of the wings appear coloured through optical interference rather than pigments. Adult moths have a wingspan of 7–9 centimetres (2.8–3.5 in). It is endemic to Madagascar, where it is found throughout the year in most parts of the island, with peak populations between March and August.
Females lay about 80 eggs under the leaves of Omphalea spp. The caterpillars are whitish-yellow with black spots and red feet and are covered in club-ended black setae. Silk spun from the mouth helps the caterpillars hold on to smooth leaves and climb back to the plant when they fall. After completing four instars, the caterpillars spin an open network cocoon. The pupal stage lasts from 17 to 23 days. Chrysiridia rhipheus is the sole specialist herbivore of the four species of Omphalea in Madagascar. Omphalea is toxic: the toxins are sequestered by the feeding caterpillar and retained in the pupal and adult stages. Thousands of these moths migrate between the eastern and western ranges of their host plants.