294 NATURAL HISTORY. 
to balance itself by means of some prominent tubercles 
on the last segment of the body. It then bends itself 
into a circle, and having brought the head toward the 
tail, it stretches out the two hooks of the mouth, fixing 
them into two cavities at the other extremity of the body. 
It then contracts the body from a circular to an oblong 
figure—the contraction extending in a manner to every 
part of the body. It now suddenly lets go its hold, and 
straightens the body with such violence that the noise 
produced by its hooks is very perceptible. The height 
of the leap is often from twenty to thirty times the length 
of the body, exhibiting an energy of motion which is par 
ticularly remarkable in the soft larva of an insect. A 
Viper, if endowed with similar powers, would throw it 
self nearly a hundred feet from the ground.” 
Fig. 227.—Wriggler. 
