What is the scientific name of the monarch butterfly?

The scientific name of the monarch butterfly is Danaus plexippus.

Danaus is the genus and plexippus is the species name, together forming the binomial scientific name. The monarch is native to the Americas but has also established populations in some other regions after human introduction, including parts of Australia and the Pacific.

Its orange-and-black pattern is a warning signal. Monarch caterpillars feed on milkweeds and acquire cardenolides, chemical compounds that can make the insects distasteful to many predators. Several other butterflies resemble monarchs, including the viceroy, in a classic example of Müllerian mimicry.

The name “monarch” is a common name, not a taxonomic rank. It identifies one species, whereas Nymphalidae identifies the broader butterfly family containing it.