THE CLASSIFICATION OF BUTTERFLIES
In every science it is necessary to manipulate a large number of
related facts, and this cannot be done unless the data are arranged
in some systematic and orderly fashion. In order to make use of the
facts about butterflies, one must know something of the relation of one
butterfly to another, and the relation of butterflies in general to the
rest of the animal kingdom.
SUBKINGDOMS, CLASSES, ORDERS, AND SUBORDERS
Members of the animal kingdom which have no spinal column, but only
an external skeleton composed of horny rings, are assigned to the
subkingdom _Arthropoda_. Arthropods which have six legs are grouped
together in the class _Insecta_. Insects with scales on their wings are
assigned to the order called _Lepidoptera_. This order is divided into
two suborders, the _Rhopalocera_ or butterflies and the _Heterocera_
or moths. Butterflies fly in the daytime, and have slender antennae
with club-like knobs at the ends; moths are usually nocturnal or
crepuscular, and their antennae are not knobbed, but are thread-like,
feather-like, or hooked at the extremity.
THE FOUR FAMILIES
The suborder Rhopalocera is divided into four families: the
_Nymphalidae_, the _Lycaenidae_, the _Papilionidae_, and the
_Hesperiidae_.
The _Nymphalidae_ or four-footed butterflies make up the largest
family; the first pair of legs are much smaller than the others, and
are quite useless for walking. Most of the Nymphalidae are large or
medium-sized butterflies. The caterpillars are usually provided with
spines or fleshy protuberances, and the chrysalids are always suspended
by the tail.
The _Lycaenidae_ or gossamer-wings are the bright little butterflies
known as “blues,” “hair-streaks,” and “coppers.” The males do not use
the first pair of legs in walking, but the females do. The caterpillars
are small and usually slug-shaped, and the chrysalids are held closely
attached to some object by a girdle of silk.
The _Papilionidae_ is the family of the swallowtails and allied forms.
Both sexes use all six feet in walking. The butterflies are usually
large or medium-sized; many of the caterpillars produce disagreeable
odors; the chrysalids are suspended by the tail and provided with a
girdle of silk, but not drawn up to the surface to which they are
attached, as in the case of the _Lycaenidae_.
The _Hesperids_ or skippers are small butterflies with thick, moth-like
bodies and a peculiar manner of flight. Both sexes have six walking
feet. The caterpillars are smooth and thin-necked, with large globular
heads. The chrysalids are usually enclosed in a flimsy cocoon of leaves
fastened together with a few silk threads.
SUBFAMILIES, GENERA, AND SPECIES
Each one of these four families is divided into several subfamilies;
each subfamily is divided into several genera, and each genus is
divided into several species, all of these divisions being based on an
increasing anatomical similarity. Thus the common Milkweed Butterfly
belongs to the class _Insecta_, the order _Lepidoptera_, the suborder
_Rhopalocera_, the family _Nymphalidae_, the subfamily _Euploeinae_,
the genus _Anosia_, and the species _Plexippus_.
THE VALUE OF SCIENTIFIC NOMENCLATURE
One may well ask why we do not simply say “milkweed butterfly” and
have done with it, but this term refers merely to the fact that the
caterpillar feeds upon a certain plant, while _Anosia plexippus_
places the specimen definitely in the scientific scheme of things, and
designates important structural distinctions which have nothing to do
with milkweeds. The average American is prone to call any insect a
“bug” or “moth-miller” or some such unenlightening name, so that many
butterflies have no common English name at all, while others have many
different names which vary widely in different parts of the country.
Besides, the Greek and Latin names are understood by scientists in all
countries, and are less liable to corruption than terms taken from the
modern languages.
There are difficulties enough in the scientific nomenclature, without
complicating matters by the introduction of popular names. It is a
fixed rule in science that the first man to discover and describe a
species has the right to name it, and that whatever name he chooses
shall be used by everybody forever, but scientists are only human after
all, and are always anxious to discover new species and name them after
their friends or sweethearts. It often happens that a single species
is described independently by several authors, each of which applies a
name of his own devising; in this case the first is the real name, and
the others are called synonyms.
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_.