The monarch butterfly or simply monarch (Danaus plexippus) is a milkweed butterfly (subfamily Danainae) in the family Nymphalidae. t is amongst the most familiar of North American butterflies and an iconic pollinator, although it is not an especially effective pollinator of milkweeds. Its wings feature an easily recognizable black, orange, and white pattern, with a wingspan of 8.9–10.2 cm (3.5–4.0 in). The name "monarch" is believed to have been given in honor of King William III of England, as the butterfly's main color is that of the king's secondary title, Prince of Orange. Although larvae eat only milkweed, adult monarchs feed on the nectar of many plants. In both caterpillar and butterfly form, monarchs are aposematic, warding off predators with a bright display of contrasting colors to warn potential predators of their undesirable taste and poisonous characteristics.

From Wikipedia article at https://en.wikipedia.org/wiki/Monarch_butterfly which is released under the Creative Commons Attribution-Share-Alike License 3.0.