THE CABBAGE-CATERPILLAR 303 



having grown to the desired extent, left the cabbages, 

 one by one, and began to roam about the walls. None 

 of them fixed himself there or made preparations for the 

 transformation. I suspected that they wanted the choice 

 of a spot in the open air, exposed to all the rigors of 

 winter. I therefore left the door of the hothouse open. 

 Soon the whole crowd had disappeared. 



I found them dispersed all over the neighboring walls, 

 some thirty ^yards off. The thrust of a ledge, the eaves 

 formed by a projecting bit of mortar served them as a 

 shelter where the chrysalid moult took place and where 

 the winter was passed. The Cabbage-caterpillar pos- 

 sesses a robust constitution, unsusceptible to torrid heat 

 or icy cold. All that he needs for his metamorphosis is 

 an airy lodging, free from permanent damp. 



The inmates of my fold, therefore, move about for a 

 few days on the trelliswork, anxious to travel afar in 

 search of a wall. Finding none and realizing that time 

 presses, they resign themselves. Each one, supporting 

 himself on the trellis, first weaves around himself a thin 

 carpet of white silk, which will form the sustaining 

 layer at the time of the laborious and delicate work of 

 the nymphosis. He fixes his rear-end to this base by a 

 silk pad and his fore-part by a strap that passes under 

 his shoulders and is fixed on either side to the carpet. 

 Thus slung from his three fastenings, he strips himself 

 of his larval apparel and turns into a chrysalis in the 

 open air, with no protection save that of the wall, which 

 the caterpillar would certainly have found had I not 

 interfered. 



