THE AMERICAN SILK WORM. 147 
which was placed in another box containing ice and salt ; 
the temperature soon descended to four degrees below 
zero. They were allowed to remain in this refrigerator 
for half an hour. When taken out, the chrysalids were as 
hard as a piece of ice; they were immediately put into 
acold room. Several days after this, the temperature of 
the room being above the freezing point, the chrysalids 
gave signs of life by moving the abdomen. Some years 
ago, wanting to keep a cocoon in my collection, I thrust 
; a pin through it, and it passed through the body of a liv- 
ing chrysalis inside of it; this was done in the month of 
3 October. Nine months after, in June of the following 
year, I was astonished to find a great commotion in one 
of the boxes of my collection; all the specimens were 
broken, and I found the cocoon which had been pinned in’ 
the box, detached and open at one end, and the antennæ, 
head and legs of the moth projecting out of it; the insect 
was still living and could not come out, as the pin passing 
through it had also transfixed the cocoon. Through this 
insect had been thrust, for nine months, a pin covered with 
verdigris, and yet had not been killed by it! Naturalists 
state that it is very important, when transporting cocoons 
in a box, to pierce the box with holes so that the air may 
penetrate it, as if air was needed for a chrysalis inside 
the cocoon. Having observed how close and air-tight the 
cocoon of the Polyphemus seems to be, I could not con- 
ceive that air was needed for it to breathe. Desirous of 
ascertaining whether my idea was correct, I took three 
_ €ecoons, and at two different times I covered them care- 
fully with a thick coating of starch, allowing the first 
coating to dry before putting on the second one. After 
ae = € cocoons were covered at three different times 
_ With a heavy coating of shellac varnish ; thus the cocoons 
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