THE METAMORPHOSIS OP INSECTS. 243 



silk, and then proceeds to spin its cocoon in the same 

 way that the Silkworm does, making it of the same shape. 

 The loose silk between the cocoon and the outer cover- 

 ing is blanketing for the purpose of warmth. By these 

 means the pupa or chrysalis is secured against dampness 

 and cold, and amid all the storms of winter is even more 

 safe from harm than an infant in its cradle under the 

 watch of an anxious mother. 



416. As in the case of the Silkworm Moth, the Ce- 

 cropia always comes out at the smaller end, and here 

 both the cocoon and the outer covering are made less 

 close and strong than in the other portions. In New 

 England this Moth comes forth in June. Last year I 

 obtained from my garden two cocoons which were near 

 each other on a currant bush. I gave one to a lad living 

 on Staten Island, and retained the other myself. His 

 Moth came out three weeks before, mine, corresponding 

 with the advance of the season there before ours. When 

 mine emerged I caught the same evening in my house 

 two others, and on the following evening three more. 

 As we saw none before or after, this seems to show that 

 these Moths come forth almost simultaneously in the 

 same locality. 



417. Dr. Harris, in his work on the Insects of New 

 England, recommends a trial of the manufacture of silk 

 from the cocoons of the Cecropia and some other of 

 our large indigenous Moths. "Their large cocoons," 

 he says r " consisting entirely of silk, the fibres of which 

 far surpass those of the Silkworm in strength, might be 

 employed in the formation of fabrics similar to those 

 manufactured in India from the cocoons of the Tusseh 

 and Arindi Silkworms, the durability of which is such 

 that a garment of Tusseh silk is scarcely worn out in the 

 lifetime of one person, but often descends from mother 

 to daughter ; and even the covers of palanquins made 

 of it, though exposed to the influence of the weather, 

 last many years. Experiments have been made with 



