252 THE INFANCY OF ANIMALS 



length of living under water. These are the caterpillars 

 of certain moths of the family Eripterotidce, and of these 

 those of the South American genus Palustra are the most 

 remarkable. They, like their other aquatic relations, are 

 very hairy, and swim by rapidly coiling and uncoiling their 

 bodies. When the end of this life in the underworld comes, 

 one of them proceeds to form a cocoon, and so soon as 

 this is finished its fellows come successively and add theirs 

 to it, forming a compact mass. 



But why ? What prompts this singular behaviour ? 

 And how comes it that they pass their caterpillar life under 

 water, a mode of existence one would have supposed not 

 only utterly foreign, but utterly impossible to a cater- 

 pillar — for to this day no one has succeeded in discovering 

 how they have solved the difficult problem of breathing 

 under water ? 



And now let us take a rapid survey of the final stages of 

 larval life through which aU must pass before they can 

 enter upon that short, but glorious period, when they can 

 range from flower to flower, borne on wings of gorgeous 

 colours, in order that they may drink deep draughts of 

 nectar drawn up through that quill of marvellous mechan- 

 ism known as the proboscis. 



The caterpillars of butterflies, when they feel the end is 

 near, generally crawl up the stem of their food-plant, or 

 seek some cranny in the neighbourhood, and then suspend 

 themselves head downwards. This done, they close their 

 eyes, so to speak, and go to sleep. Then a strange thing 

 happens. Beneath the worm-like caterpillar skin a shell 

 of horny consistency and angular shape is formed ; and 

 as soon as this is complete, the wrappings of its childhood 

 fall away and reveal — a chrysalis. This certainly bears 

 no likeness to any living thing, but its surface, if carefully 



