The Zoologist — June, 1£68. 1230 



the cocoon. If there is any elaboration of the food in the chrysalis, 

 the process must be very slow, and surely no air is needed to 

 accomplish it, nor any food, except what little food is in the stomach. 

 The most striking phenomena manifested by life is the assimilation 

 and elimination of food ; but to assimilate, the animal must take food, 

 either in the solid or gaseous form. We know that the chrysalis 

 cannot eat ; breathing is very problematical. Before changing into a 

 chrysalis, the worm evacuates all the contents of its stomach ; so, in 

 my opinion, the chrysalis does not breathe, or, if at all, it is so very 

 slight as to be insignificant. 



There is not much possibility of being able to obtain two broods of 

 the silk-worm in the same year in this latitude. The earliest date at 

 which I have obtained cocoons was the 1st of August, twenty-two days 

 after the moth hatched from the cocoon. On the 5th of September I 

 had young larvae, but the heat being less in this month than in July 

 and August, the larvae did not grow so rapidly, and the moulting did 

 not take place so regularly. The first moulting took place on the 

 fourteenth day, the second the twenty-third day, the third the thirty- 

 sixth day; on the 1st of November, or fifty-six days after their birth, 

 they had not accomplished the fourth moulting. I could not continue 

 the experiment, as I left for Europe the 2nd of November ; but they 

 had frozen several times, and the leaves were very hard ; in fact, I do 

 not believe that the second brood would have come to maturity. I do 

 not see that it would be of any advantage to obtain two broods, as the 

 moths do not all come out of the cocoon at the same time, but some- 

 times there are two months between the first and the last; so the 

 process of rearing can go on permanently all summer, which is equal 

 to having two broods. 



Cocoons can be retarded in hatching out by being put in a very 

 cold room — an ice-house, for instance; in this way they can be made 

 to hatch another year, or nearly twenty-one months after they have 

 been in the cocoon. In fact, the time of their appearance can be put 

 back for an indefinite period, as life is nearly suspended. Reaumur 

 states, that, at the time he was writing, he had in his cellar pupae 

 which had been there for five years, which were still living. I have 

 myself kept pupae of Sphingidae, of hawk-moths, for three years in my 

 cellar. At the time I went to Europe, they were still living, but on 

 my return I found that the rats had eaten them. 



