36 
FINDING NATURE’S TREASURES 
“Caterpillars do not make a web like the spider’s 
web,” replied Uncle Jack. “But the Cecropia builds a 
house of silk to live in when it is a pupa. But it does 
not go down into the ground like the humming-bird cater¬ 
pillar does. The house, where the Cecropia pupa lives 
while it is changing from a caterpillar into a moth, is 
called a cocoon.” 
“Where does it get the silk?” asked Marylee. 
“It comes from a tiny hole in its lower lip,” replied 
Uncle Jack. “Every time that it moves its head, it makes 
more silk. It will keep on making silk until the cocoon 
is finished. Then it will go to sleep inside.” 
“What is that big thing on this branch?” asked Buddy. 
He had gone around to the other side of the bush to see 
if he could find some more caterpillars. 
“That is a Cecropia cocoon all finished,” said Uncle 
Jack, when he looked at what Buddy had found. “WeTl 
cut it open when I get out my knife.” 
Uncle Jack broke off the little branch that had the 
cocoon fastened to it. 
“Why do you need your knife?” asked Marylee. “Can’t 
you tear open the cocoon with your fingers?” 
“No, not with my fingers,” said Uncle Jack. “The 
cocoon is as strong as silk cloth.” 
Uncle Jack began to cut the silk. The outside cover 
was more like very strong paper than it was like cloth. 
There were some loose threads of silk under the outside 
cover. Under the loose threads was the real cocoon, 
which was smaller and much stronger than the outside 
