A patch of eggs and the minute caterpillars or larvæ nearly emerged
from them are seen on the leaf. These tiny eggs are at first quite
white or pale yellow, and form an object for the microscope of
remarkable beauty, which is worthy of the examination of all who take
an interest in the garden and its insect life. An egg magnified is
drawn at the bottom left-hand corner of the woodcut. When the eggs are
near the hatching point they darken in color, and a magnifying glass
reveals through the delicate transparent shell a sight which fills the
observer with amazement; the embryo caterpillar is seen in gradual
course of formation, and if patience and warmth have permitted it, the
observer will witness slight movements within the life-case, and
presently the shell will break and a black head with moving jaws will
be thrust out; the little caterpillar unfolds and slowly crawls away
from the egg-shell, and inserts its jaws into the green leaf. It is
curious to witness how judiciously the little creatures avoid crowding
together, but strike out in different directions, and thus they make
sure of a plentiful supply of food, and distribute the effects of
their depredations. These caterpillars eat continually, and hence
rapidly increase in size, until they present the appearance shown in
our drawing at the bottom of the illustration, which is a full grown
caterpillar.
[Illustration: THE CABBAGE AND PEACOCK BUTTERFLIES.]
It will be observed that this insect is composed of thirteen segments
from head to tail, which is a distinctive characteristic of all
insects both in the larval and perfect states; but in the case of this
and most other caterpillars these segments are sharply defined and
readily recognized. It will also be noticed that the three segments or
"joints" nearest the head bear a pair of legs each; these are the real
feet, or claspers, as they are sometimes termed, which develop into
the feet of the future butterfly. There are four pairs of false feet
or suckers, which adhere to the ground by suction, and which disappear
in the butterfly. On the last or tail end is a fifth pair of suckers
also, which can attach themselves to a surface with considerable
force, as any one can attest who has noticed the wrigglings of one of
these caterpillars when feeling for new feeding ground.
The caterpillar now ceases to eat, and quietly betakes itself to a
secluded corner, where in peace it spins a web around its body, and
wrapt therein remains quiescent, awaiting its change into the
butterfly. Although so dormant outwardly, activity reigns inside;
processes are going on within that chrysalis-case which are the
amazement and the puzzle of all naturalists. In course of time the
worm is changed into the beautiful winged butterfly, which breaks its
case and emerges soft and wet; but it quickly dries and spreads its
wings to commence its life in the air and sunshine. The chrysalis is
represented in the figure on the left. The butterfly, it will be
recognized, is one of the common insects so familiar to all, with
strongly veined white wings, bearing three black spots, two on the
upper and one on the lower wing, and dark coloring on the corner of
the upper wings. The antennæ, as with all butterflies, are clubbed at
the extremity--unlike moths', which are tapering--and the large black
staring eyes are the optical apparatus, containing, we are told,
thousands of lenses, each a perfect, simple eye.
The wings derive their chief coloring from the covering of scales,
which lie on like slates on a roof, and are attached in a similar
manner. A small portion of the wing magnified is represented at the
bottom right hand corner, and detached scales more highly magnified
next to it, exhibiting somewhat the form of battledoors.