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cases, to mature and transform into the 

 adult stage after the caterpillar has built 

 its cocoon, and thus many parasites lose 

 their lives, since they are not always able 

 to escape from the cocoon. A cocoon 

 will sometimes be found filled with these 

 small insects, which have not been able 

 to make their escape, and have thus died 

 in prison. 



The adult larva, unlike Prometha, usu- 

 ally spins its cocoon not attached to a 

 leaf, but along a stem ; sometimes, how- 

 ever, they may be placed in other situa- 

 tions. 



In about two weeks after the cocoon 

 has been spun, the larva transforms into 

 a chrysalis, in which stage it hibernates 

 during the winter, and from which it 

 emerges in May or June. 



During the winter, when the leaves are 

 not on the trees and shrubs which are fre- 

 quented by these larvae, a large number 

 of cocoons may easily be collected. These 

 should be kept out of doors during the 

 winter, for if kept in a warm room they 

 will emerge during the winter or so early 

 in the spring that food cannot be secured 

 for the larvae. 



If one secure a number of old cocoons, 

 from which the moths have failed to 

 emerge, and cut them open longitudinal- 

 ly, he may I'earn many interesting facts. 

 A dead and dry mummified looking larva 

 or chrysalis may be found, or, what is 

 even more interesting, no trace of the 

 larva or chrysalis may be present, but 

 only a mass of small white, paper-like 

 cocoons. These have been left by a col- 

 ony of little wasp-like parasites which 

 may occur in such large numbers that 

 there is scarcely room for all to spin their 

 cocoons, so that on account of being so 

 closely crowded together, they are 

 moulded into a mass of cocoons having 

 the form of the cavity formerly occupied 

 by the larva. 



The cocoons of Cecropia are composed 

 of two parchment-like layers of silk 

 which are generally very dense and 

 strong. The space between these two 

 layers contains loosely spun threads of 

 silk like a layer of packing material. The 

 larvae seem normally to u.ake three varie- 

 ties of cocoons ; one kind is very loosely 

 constructed, much larger than the ordi- 



nary form and not attached to a twig, but 

 found in the grass or in shrubs near the 

 ground. The two other forms of cocoons 

 are much smaller and more closely 

 woven, but differ in size ; female moths as 

 a rule emerging from the larger cocoons, 

 and males from the smaller ones. 



Dead larvae are sometimes found in 

 cocoons which are practically of a single 

 thickness ; there being no space between 

 the outer and inner layers. The hollow 

 skins of the larvae found in such cocoons 

 clearly show that this unusual cocoon is 

 due to the intluence of parasites upon the 

 larva. 



In the upper open end of the cocoon, 

 kernels of wheat, corn, beechnuts and 

 even acorns have been found. How these 

 get in this position seems to be quite a 

 puzzle. In opening twenty or thirty 

 cocoons, five or six kernels of corn have 

 been found, thus showing that this oc- 

 currence is by no means rare. Chicka- 

 dees and blue-jays have been given the 

 blame for this work, since these birds are 

 thought to have the habit of hiding food. 

 The inverted outer layer of the cocoon 

 clearly shows, in some cases, that the ker- 

 nel of corn has been thrust into the 

 cocoon with some force. 



The head of the pupa lies at the small 

 end of the cocoon, where the texture is 

 less dense, and thus, when it is ready to 

 transform into the moth, the head is in 

 the best position for easy escape from the 

 cocoon. But this provision alone is not 

 sufficient to make sure the escape. At 

 the time of emergence, the pupa secretes 

 a fluid which escapes from the mouth and 

 by moistening the cocoon softens the 

 glue-like material which binds together 

 the threads, thus making it possible for 

 the freshly emerging moth to crowd its 

 way between the fibres, and thus secure 

 its freedom. When the moth first crawls 

 out of the cocoon, its heavy body and 

 small folded wings show but little resem- 

 blance to the fully-expanded moth. By 

 degrees, however, the wings expand and 

 become more rigid, the colors brighten, 

 and finally the mature moth is developed. 



The Promethea Moth is only about 

 one-half the size of Cecropia, and the two 

 sexes are very different in appearance ; so 

 much so that one would not at all think 



