234 THE INSECT WOBLD. 



by M. Eugene Robert. These are leaves of paper, of a peculiar 

 manufacture, pierced with holes proportioned to the size of the 

 worms which are to pass through them. The paper net can be 

 used advantageously also for separating the worms that are too 

 near together, or, as they say, for the dedoublement. Formerly, 

 the delitement and the dedoublement were done by hand a tedious 

 work, and one that presented serious disadvantages. Now-a-days, 

 as we have seen, the worms themselves undertake these two perilous 

 operations. 



At the second age they still cut the leaves for the worms, but 

 into larger pieces, and proportioned to their size. During the 

 day, the temperature of the room ought to be kept to 21 Cen- 

 tigrade, but it may be lowered by 1 or 2 during the night. 

 Towards the end of this age they have only four meals. When 

 the worms are on the point of going to sleep, their meals are 

 decreased. 



During the third age the number of the meals is kept to four, 

 the first being given towards five o'clock in the morning, and 

 the last between ten and eleven o'clock at night. The leaf is cut 

 into much larger pieces, and distributed as equally as possible. 

 The delitement and the dedoublement are proceeded with as in the 

 preceding age. One begins to find pretty often during this period 

 of the life of worms, some luisettes, that is to say, worms which 

 have not strength enough to moult. They are larger than those 

 just woke up, and that have not as yet eaten, and are shiny. They 

 must be carefully removed, for they will not be long before they 

 die, and infect the air of the room. 



During the fourth age they no longer cut the leaves, but give them 

 a great deal more at once. The result is that the litters increase 

 in thickness, and that the delitement must be performed oftener ; for 

 the rest, four meals are always necessary. Many luisettes may be 

 seen during the fourth age. The moult which follows the fourth 

 age is the most critical phase in the life of the silkworm. During 

 their sleep they are a prey to acute suffering, and are plunged 

 into a state of lethargy which resembles death. The dryest and 

 cleanest litters diffuse very soon a sickly smell. This moult 

 lasts from thirty-six to forty-eight hours. During this time the 

 room should be kept to at least 22 Centigrade. 



