254 FIELD, FOREST AND FARM 



ing ordinarily ends the trouble. Accordingly any 

 one who should hereafter be afraid of caterpillars 

 would not deserve the privilege of chasing butterflies. 



"Every larva is a gluttonous eater, because it must 

 grow big and accumulate the wherewithal for its sub- 

 sequent changes of form. Nor are caterpillars lack- 

 ing in response to this serious duty. The future 

 butterfly's welfare is at stake. Made solely for eat- 

 ing, the larvae gnaw and browse unceasingly. Each 

 one has its own particular kind of sustenance, its 

 chosen plant, and nothing else meets the require- 

 ments. The larva of the Vanessa selects the nettle 

 and turns with aversion from all substitutes; that 

 of the Pieris, a white butterfly with black spots, will 

 have only the cabbage ; that of the Machaon, a but- 

 terfly with large wings that end in a sort of tail, 

 feasts on fennel; and so of others. 



"After attaining the full size assigned to them 

 by nature, caterpillars, like other larva?, prepare for 

 their transformation. Some shut themselves up in 

 a cocoon made from a silken thread that they spin 

 from their mouth, while others content themselves 

 with binding together, by means of the small supply 

 of thread at their disposal, particles of earth, bits of 

 wood, and hairs plucked from their own body. Thus 

 is obtained, at small expense, a sufficiently substantial 

 temporary abode. Finally, still others, especially 

 among the butterflies that fly in the daytime, merely 

 seek a retreat on the side of some wall or against 

 a tree-trunk, and there suspend themselves in a 

 girdle of silk. 



