le boss of silk,
gripped it with his hind-claspers, and swung with easy confidence head
downwards. For three days he hung thus motionless, yet within him there
was a lively motion.

From the time he left the egg his life had been a dual one. The eye saw
nothing but the outward mask, the caterpillar-form. Within this living
vehicle that moved and spun and fed, lived the true butterfly--life within
life, being within being.

[Illustration: THE CROWDED SEGMENTS OF HIS BODY RECALLED THE PILE OF
VELVET.]

The caterpillar mask had done its work, and having done its work, must
die. Yet one can hardly call such dissolution death. As it hung suspended,
all the marvellous mechanism which had formed a moving, eating, spinning,
sentient being, was absorbed into the chrysalis it covered. Merely the
outer empty shell remained.

On the fourth day this shell split cleanly at the tail, and, from the
opening, the hind part of the chrysalis emerged. It jerked from side to
side, to all appearance aimlessly. Yet there was method in its madness. A
side-swing forced it deep into the boss of silk, and, in a moment, the
hooks that studded its extremity were fast entangled. The chrysalis had
its _point d'appui_.

[Illustration: ON THE CHRYSALIS HEAD WERE TWO SHORT-POINTED HORNS.]

Again the old skin cracked, this time behind the neck. The chrysalis head
was free. On it were two short, flattened, pointed horns. A jerky movement
of the shoulders followed--first expansion, then contraction. At each
expansion the old skin slipped a trifle upwards. Turn by turn the segments
of the body did their work, until it lay in gathered folds about the tail,
just as the pushed-off stocking lies about the ankle.

But even so, the task was not completed. The skin must be got rid of. Its
dull white mass, with dangling skeleton horns, was too conspicuous. Nature
had armed the chrysalis with the needful tools, a grip attachment and a
set of tiny sharp-edged hooks. The skin was fast entangled in the boss of
silk. The chrysalis secured an independent foothold (using as
stepping-stone the skin itself), spun itself from side to side, and cut
the threads that bound it. It jerked lightly from leaf to leaf, until it
reached the ground. The second change was accomplished.

[Illustration: COLOUR AND FORM COMBINED THEIR SKILFUL MIMICRY.]

[Illustration: ITS FORM THE FORM OF THE SALLOW-LEAF.]

Outwardly the chrysalis was nothing but an extra leaf. Colour and form
c