Pronunciation: (bāt'sē-un), [key] Ecol.
the protective resemblance in appearance of a palatable or harmless species, as the viceroy butterfly, to an unpalatable or dangerous species, as the monarch butterfly, that is usually avoided by predators. Cf. Müllerian mimicry.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.