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Home Xatikk-Stidv Course. 



Cecropia caterpillar shedding its skin. 



on the caterpillars during these different molts; in the third stage it 

 has been observed that the tubercles usually blue are sometimes black. 



After the last molt the caterpil- 

 lar eats voraciously for perhaps 

 two weeks or longer and then 

 begins to spin its cocoon. 



The cocoon. — This is the co- 

 coon found most often on 

 our orchard and shade trees, 

 and is called by the children 

 the " cradle cocoon." since it is shaped like a hammock and hung close 

 below a branch ; 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 paper- 

 like and the inner one thin and firm; between these walls is a matting 



of loose silk, 

 showing that the 

 insect k n o w s 

 how to make a 

 home that will 

 protect it from 

 winter weather. 

 It is a clever 

 builder in an- 

 other respect, 

 since at one end 

 of the cocoon 

 it spins the silk 

 lengthwise in- 

 stead of cross- 

 wise, thus mak- 

 ing a valve through which the moth can push as it issues in the spring. It 

 is very interesting to watch one of these caterpillars spin it>^ cocoon. It 

 first makes a framework l)y stretching a few strands of silk, which like all 

 other caterpillars, it spins from a gland opening in the lower li]) ; it then 

 makes a loose net work on the supporting strands, and then begins laying 

 on the silk by weaving its head back and forth leaving the sticky thread 

 in the shape of connecting M's or figure 8's. \*ery 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 cater- 

 pillar is obliged to compress itself in order to fit within it. This achieve- 

 ment wcndd be somethino- like that of a man who built around himself a 



Cecropia caterpillar spinning its cocoon. 



