A North American butterfly species in the cosmopolitan genus Limenitis. It has been studied for its evolution of mimicry, and for the several stable hybrid wing patterns within this nominal species; it is one of the most dramatic examples of hybridization between non-mimetic and mimetic populations.
Limenitis arthemis can be split into two major groups, mainly based on one physical characteristic: the presence of a white band along the wings. Individuals of the northern group, called white admirals, have a conspicuous white band that traverse both the dorsal and ventral surfaces of the wing, while those of the southern group, called red-spotted purples, lack that trait as they have evolved to mimic the poisonous pipevine swallowtail (Battus philenor). Due to overlap in distribution among the two major groups, intermediates are numerous as hybridization occurs frequently.