In writing about butterflies it is not customary to spell out the generic name; one does not write Dione vanillae, but merely D. vanillae. It is usual also to add the name of the man who first named the species, so that the name becomes D. vanillae, Linnaeus, or D. vanillae, Linn. In conversation one may omit the name of the genus altogether, and refer to the butterfly simply as Vanillae. It is well to remember that scientific Latin in this country is pronounced in the insular fashion—that is, the words are pronounced as if they were English.
VARIETIES
Sometimes the individuals of a species differ in different parts of the country; these different forms are called varieties, and are designated by a varietal name added to the generic and specific names. Papilio turnus, Linn. is a large yellow swallowtail, but in the southern part of its range some of the females are black. The black female was formerly regarded as a distinct species, and Linnaeus named it Papilio glaucus, but when it was reared from eggs laid by a yellow female it was recognized as a variety, and is now known as Papilio turnus, Linn., var. glaucus.
CHAPTER VI
THE FOUR FAMILIES
As we said in the chapter on Classification, American butterflies fall naturally into four great groups called families: the Nymphalidae or Four-footed family, the Lycaenidae or Gossamer-winged family, the Papilionidae or Swallowtail family, and the Hesperiidae or Skipper family.
THE FOUR-FOOTED BUTTERFLIES
The largest family of butterflies in America is the Nymphalidae, and its members are called four-footed butterflies because the front legs are so small as to be useless, leaving only four walking feet. Most of the butterflies are large or medium-sized, the caterpillars are usually provided with spines or fleshy protuberances, and the chrysalids are always suspended by the tail. The family is divided into five subfamilies; the Euploeinae, the Heliconiinae, the Nymphalinae, the Satyrinae, and the Libytheinae.
THE EUPLOEINAE
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.