Emperor butterfly

The emperor butterfly (known as the emperor prior to ) is a bug in the. It first appeared in and has appeared in all subsequent games. It is the only butterfly that can be found in the night.

In the games that the emperor butterfly appears in, it is a rare bug that the player can encounter, and can be found flying around flowers. In, it can be caught from summer to the start of fall and from winter to the start of spring.

Donating to the museum
As with all fish and bugs in the, the emperor butterfly can be donated to the museum by talking to Blathers, the curator. When donating, Blathers will say the following upon receiving the Emperor Butterfly:

In
After donation, the emperor can be found fluttering around the flowers in the first room of the insect exhibit.

In
It can be found in the bottom terrace, flying near or resting on the flowers with any other butterflies.

In
Upon being donated, the butterfly can be found in the first room of the bug exhibit resting on flowers with the other butterflies. The exhibit has this to say about the emperor butterfly:

In
When the player donates an emperor butterfly, Blathers will say this about it before thanking the player for the donation:

Real-world information
Morpho menelaus, more commonly known as the Blue Morpho, is an exotic butterfly that can be found in Central and South America. It feeds primarily on rotten fruit, but in the larval stage, frequently eats other larvae of the same species. The in-game name Emperor Butterfly, while not used to refer to its species, may originate from the species' family, Nymphalidae, which is sometimes known as the Emperors.

Etymology
Morpho stems from the Greek word for form, and therefore means 'changed'. This may be a reflection of the species' iridescence, which has the quality of changing colors in the light. Menelaus was a legendary king of Sparta who married Helen of Troy.