230 COMMON BRITISH INSECTS. 



foothold for the legs. Thus, the caterpillar proceeds 

 by bringing its body into the loop-like form and 

 stretching it out for another hold. This may seem an 

 awkward mode of progression, but it is nothing of 

 the kind. There is even a sort of grace about the 

 movement, and the caterpillar gets along at a wonderful 

 pace, forming its successive loops with a rapidity that 

 seems almost incredible. 



The muscular strength of these caterpillars is 

 wonderful. Most of us have seen acrobats fix their 

 feet to an upright pole, or grasp it with their hands, 

 and stretch out their bodies horizontally. This atti- 

 tude requires great muscular powers very carefully ap- 

 plied, as those readers well know who have practically 

 studied gymnastics. The leverage is so great that the 

 strongest and most accomplished gymnast cannot 

 maintain his position for any length of time, the atti- 

 tude requiring the strongest possible strain on the 

 muscles. Yet this attitude is not only easy to the 

 Geometrae, but appears in some cases to be the chosen 

 attitude of rest. 



Several of these larvae pass a large portion of their 

 time stretched out at full length from the twig on 

 which they are clinging. In this attitude they so 

 exactly resemble twigs, that the sharpest eye can 

 scarcely detect them, and even the most experienced 

 entomologists are often deceived, taking veritable 

 twigs for caterpillars, and caterpillars for twigs. None 

 of the caterpillars are hairy, and their smooth bodies, 

 often furnished with blunt spikes or humps, bear the 

 most curious resemblance to the smooth-barked, bud- 

 bearing twigs of the trees on which they live. Such 



