1238 The Zoologist— June, 1868. 



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 a cold 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 living chrysalis inside of it; this was done in the month of 

 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 antennae, 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 piu 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 conceive that air was needed 

 for it to breathe. Desirous of ascertaining whether my idea was 

 correct, I took three cocoons, and at two different times I covered 

 them carefully with a thick coating of starch, allowing the first coating 

 to dry before putting on the second one. After this the cocoons were 

 covered at three different times with a heavy coating of shellac 

 varnish ; thus the cocoons were made perfectly air-tight. They were 

 kept in a cold dry room all winter. In July the moths came out 

 perfectly healthy, the fluid they discharge through the mouth having 

 perfectly dissolved the starch and varnish. So these insects had been 

 nine mouths with no air, except the very small volume enclosed in the 

 cocoon, and they had accomplished their transformation just as well 

 as if the air had been allowed to come into the cocoon. 



It seems to me that when once enclosed in the cocoon, the pupa is 

 in a transitory state. The process of assimilation, at least during the 

 cold days, seems to have ceased. In the stomach of chrysalids can 

 be found an albuminous, greenish substance; probably it is a food 

 which can be assimilated, or at least transformed into some of the 

 liquids which are discharged by the perfect insect when coming out of 



