AND THE LOWER ANIMALS. 00 



takes place. Moreover, this growth is not gradual, 

 as in most other animals. We may describe it as 

 occurring suddenly, and by a series of formative leaps 

 taken at each of those periods ordinarily called moult- 

 ings. In fact, as soon as it leaves the egg the young 

 caterpillar eats with a voracity too familiar to our gar- 

 deners, but, nevertheless, does not increase in size. 



After some days this enormous appetite is lost; 

 the caterpillar becomes quite languid, and its skin 

 loses its colour and appears to wither. It then crawls 

 away to some sheltered locality. If we follow it to 

 its retreat, we shall see it attach itself firmly to the 

 ground, alternately contracting and inflating its body 

 and twisting it about in every way ; then resting for 

 a while, as if completely exhausted, and finally com- 

 mencing anew. Sometimes whole hours are spent 

 before we can see the object of all these tiresome 

 operations. Eventually the skin bursts at the third or 

 fourth ring, and splits in a straight line from one end 

 of the body to the other. The caterpillar now pushes 

 out first its head and afterwards its entire body, and 

 appears in a new skin as flexible and as brilliantly- 

 coloured as ever. It has also increased in size, so 

 that it would be quite impossible to inclose it in the 

 case which before enveloped it. Its organs have in- 

 creased in volume, but having been pent up and com- 

 pressed by the old skin, when suddenly liberated they 

 attained their proper size, as it were, through their 

 natural elasticity. 



There are several moultings gone through before the 

 caterpillar arrives at its adult size and acquires its final 

 characters. At this period we can distinguish but 

 two anatomical regions in our insect — the head and 



