Papilio ulysses, the Ulysses butterfly (also commonly known as the Mountain blue and/or Blue emperor), is a large swallowtail butterfly of Australia, Indonesia, Papua New Guinea and the Solomon Islands. Its size varies depending on subspecies, but the Australian butterflys' wingspan has been measured at about 4.1 in. The Ulysses butterfly inhabits tropical rainforest areas and suburban gardens. The Australian government requires breeders to obtain permits, although the species is not endangered. In the past, this butterfly had been threatened but planting pink flowered doughwood has increased its numbers.