Insect Study 



33* 







The cecropia cocoon is found most abundantly on our orchard and 

 shade trees; it is called by the children the "cradle cocoon," since it is 

 shaped like a hammock and hung close below a branch, and it is a very 



___ safe shelter for the helpless creature within it. 



It is made of two walls of silk, the outer one being 

 thick and paperlike and the inner one thin and 

 firm; between these walls is a matting of loose 

 silk, showing that the insect knows how to 

 make a home that will protect it from winter 

 weather. It is a clever builder in another 

 respect, since at one end of the cocoon it spins 

 the silk lengthwise instead of crosswise, thus 

 making a valve through which the moth can 

 push, when it issues in the spring. It is very 

 interesting to watch one of these caterpillars 

 spin its cocoon. It first makes a framework by 

 stretching a few strands of silk, which it spins 

 from a gland opening in the lower lip; it then 

 makes a loose net-work upon the supporting 

 strands, and then begins laying 

 on the silk by moving its head 

 back and forth, leaving the sticky 

 thread in the shape of connect- 

 ing M's or of figure 8's. Very 

 industriously does it work, and 

 after a short time it is so screened 

 by the silk, that the rest of 

 its performance remains to us 

 a mystery. It is especially 

 mysterious, since the inner wall 

 of the cocoon encloses so small a cell that the caterpillar is obliged 

 to compress itself in order to fit within it. This achievement 

 would be something like that of a man who should build around 



The eggs of the cecropia 

 moth. 



The cecropia caterpillar molting. 

 Photo by M. V. Slingerland. 



Full-grown cecropia caterpillars. 

 Photo by M. V. Slingerland. 



