The legging of dead skin remains in its smallest details the exact replica of the living limb.
If any one asked you to extract a saw from a scabbard exactly moulded upon the steel, and to conduct the operation without the slightest degree of tearing or scratching, you would laugh at the flagrant impossibility of the task.

But life makes light of such absurdities; it has its methods of performing the impossible when such methods are required.

The leg of the locust affords us such an instance.
Hard as it is when once free of its sheath, the serrated tibia would absolutely refuse to leave the latter, so closely does it fit, unless it were torn to pieces.

Yet the difficulty must be evaded, for it is indispensable that the sheaths of the legs should remain intact, in order to afford a firm support until the insect is completely extricated.
The leg in process of liberation is not the leg with which the locust makes its leaps; it has not as yet the rigidity which it will soon acquire.

It is soft, and eminently flexible.