THE METAMORPHOSIS OF 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 eurrant 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, “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 
