Now we have the Sphex in full costume, but she still has to free herself from the chrysalis case. This is a very fine wrap, enfolding every smallest detail of structure, and hardly veiling the shape and colours of the perfect insect. As prelude to the last act of metamorphosis, the Sphex, rousing suddenly from her torpor, begins to shake herself violently, as if to call life into her long-benumbed limbs. The abdomen is alternately lengthened and contracted, the feet are suddenly spread, then bent, then spread again, and their various joints are stiffened with effort. The creature, curved backwards on its head and the point of the abdomen, with ventral surface upward, distends by vigorous shakes the jointing of its neck and of the petiole attaching the abdomen to the thorax. At last its efforts are crowned with success, and after half an hour of these rough gymnastics the sheath, pulled in every direction, ruptures at the neck, at the insertion of the feet and petiole, and, in short, wherever the body has been movable enough to allow of sufficiently violent displacement. All these tears leave several irregular strips, the chief of which envelops the abdomen and comes up the back of the thorax. To it belong the wing sheaths. A second strip covers the head. Lastly, each foot has its own sheath, more or less dilapidated toward the base. The biggest, which forms the chief part of the whole covering, is got off by alternate dilatations and contractions of the abdomen, which gradually push it back into a little ball connected for some time with the animal by tracheal filaments. Then the Sphex again becomes motionless, and the operation is over, though head, antennæ, and feet are still more or less covered. It is clear that the feet cannot be freed in one piece on account of the roughnesses and thorns with which they are armed. These rags of skin dry up and are got rid of later by rubbing the feet together, and by brushing, smoothing, and combing the whole body with the tarsi when the Sphex has acquired full vigour.