18 



worms in their first ages, the more robust they will be; and if the 

 space can be tripled instead of doubled during the fourth age, and 

 for the fifth age be 70, 80 or 90 instead of 60 square yards, the harvest 

 of cocoons can be raised from 60 kilograms to 70, 80, or 90 kilograms 

 per ounce of eggs, the quality of silk also being superior. 



Temperature. — The silkworm is not a tropical insect, and attains its 

 best development between the temperatures of 68° and 77° F. It is 

 safe to adopt the mean between these two temperatures for the general 

 rearing. Each cultivator, however, may suit his convenience, remem- 

 bering that to fall below or to exceed the mentioned limits of heat is 

 detrimental to the worm, and will affect the quantity and the quality 

 of its spinning. 



From the second age the temperature should be from 70° to 72° F. 

 and should be kept as uniform as possible to the end of the rearing. 

 The time which elapses between one change and the following one may 

 be much shortened by raising the temperature and feeding oftener. 

 Such hasty rearings may be made in twentj^-two to twent3"-four days. 

 They are, however, to be condemned, as contrary to the nature of the 

 silkworm. Meals following each other too closel}" can not be properly 

 digested, and are likely to cause disease. Besides, hasty rearings 

 require more labor, and the service must be kept up night and day. 

 As there is danger in too high a temperature, so there is danger in 

 one that is too low (64° to 68° F.). A rearing that is too prolonged, 

 lasting over thirty-two days, is to be avoided to escape the heat of 

 June, under which the beds are more likely to ferment, causing disease; 

 the worms have less appetite and leave more leaf from one meal to 

 another; the changes are slower and less likely to occur instantane- 

 ously; and there is more risk of muscardine or calcino, a disease due 

 to a mold. 



Both hasty and tardy rearings are, therefore, to be proscribed, and 

 those conducted in twenty-eight to thirty-two days alone are recom- 

 mended. This lapse of time permits the leaves of the mulberry to 

 acquire maturity, and the growth of the worm should be relative to 

 that of the leaf on which it feeds. 



THE FIRST AGE. 



Hatchings usually occur earl}'- in the morning. The worms which 

 have crawled up through the holes of the tulle or paper to get food, 

 should not be removed before 10 a. m. to the latticed shelves covered 

 with paper to receive them. Each shelf must be marked with the 

 date of the birth of the worms put upon it, and care must be taken 

 to place on the same shelf only worms born on the same day, as a remu- 

 nerative rearing demands that such alone be raised together. 



Should the hatching occur at 68° to 70° F. , keep this temperature 

 during the first ages, and feed eight times during twenty -four hours; if 



