So far as the great majority of readers are concerned, this subfamily includes but one species--_Anosia plexippus_, the familiar Monarch or Milkweed butterfly, which is common every summer in every state in the Union. The main color of the wings is bright reddish brown, but the edges are black, and there are some white spots in the black area, particularly in the fore wings. The pale green eggs are laid upon the milkweed, and soon hatch into little black and white caterpillars. The mature caterpillar is greenish yellow with black bands, and each end of the body bears a pair of slender black “horns” or _filaments_. The stout chrysalis is green with golden markings. This butterfly has a bitter taste, and so is not molested by birds or insectivorous mammals. For this reason _Anosia plexippus_ has become very abundant and spread over a vast territory. Other butterflies which happen to resemble it share in this protection even though they have no disagreeable flavor, and this has given rise to the phenomena of _mimicry_, which is discussed elsewhere in this book. Another interesting thing about the Monarch is the fact that it does not hibernate in any stage; the eggs, caterpillars, and chrysalids die when the cold weather overtakes them, while the adults gather in great swarms and migrate southward, where they breed continuously throughout the winter. With the advent of warm weather the young southern Monarchs come north, deposit their eggs on northern milkweed, and the cycle begins again. THE HELICONIANS This is a tropical subfamily, and has only one representative within the borders of the United States. _Heliconius charitonius_, the Zebra butterfly, is a slender, long-winged, black-and-yellow species common along the roadsides of southern Florida. This butterfly has such an evil taste and odor that no known animal will eat it. The eggs are deposited upon the passion-flower vine; the young larva is hairy, but the mature caterpillar is provided with a great number of branching spines. The chrysalis is dark brown and of an odd shape; it makes a peculiar creaking sound by moving its abdomen. Another interesting fact about this Zebra butterfly is that the males are attracted to female chrysalids, and may be seen hovering about waiting for their mates to emerge. THE NYMPHALINAE