NATURAL HISTORY STUDIES 



fine booklets, and are very irritant to many 

 people and not at all to others. They give rise 

 to " sore throats " if they are breathed in, or 

 they cause a rash on the skin when the caterpillars 

 are handled. 



Appetite of Caterpillars 



Another feature in the life of caterpillars is their 

 enormous appetite. Some of them seem never to 

 stop eating, and some of them eat many times their 

 own weight in a day. The contrast between this 

 and the dainty meals of the butterfly or its not 

 infrequent fasting is very striking. The cater- 

 pillar is the feeding, growing stage ; the moth or 

 butterfly does not grow at all and often eats very 

 little. In the great majority of cases caterpillars 

 are vegetarian, and it seems that they can digest 

 only the fluid parts of their food, which sheds 

 some light on the enormous quantity eaten. 



The extraordinary voracity of caterpillars is 

 associated with rapid growth, and this with periodic 

 "moulting." As in the other jointed-footed ani- 

 mals (such as centipedes, spiders, and crustaceans), 

 the body is covered with a husk or cuticle a layer 

 not in itself living, made by the underlying living 

 skin. It is really like flexible armour ; it cannot 

 grow, and it has little expansibility. Therefore, 

 as the caterpillar grows, it is continually becoming 

 too large for its clothes, and therefore these have 

 to be moulted. Five moults very frequently occur. 

 Every moult is extraordinarily thoroughgoing, 

 involving all the many intuckings of the outer 



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