ON THE CULTURE OF SILK. 81 



gins to throw out lateral branches and suckers, which may be 

 taken with less injury to the tree. All things being ready, bring 

 the eggs from the cool depository in which they have been kept, 

 into a room, where the temperature or heat is constantly above 

 65 degrees. They will begin to hatch in from six to twelve 

 days, according to the mean degree of heat to which they are 

 exposed. Cobb says, " they hatch in a day or two after the 

 exposure." The writer of this essay hatched them the last 

 season in six, seven and eight days — during very hot weather in 

 July. Perhaps a different length of time or quantity of heat 

 may be required to hatch different parcels of eggs — according to 

 the different degrees of heat or cold to which they have been 

 exposed during the preceding winter, or to something else in the 

 previous management of them not well understood. Be this as 

 it may, the eggs should be watched daily, and as soon as the 

 worms begin to appear, strew over them tender mulberry leaves, 

 to which they will immediately betake themselves. Take hold 

 of the leaves carefully and remove them to the shelves, on 

 whi^h they are to be kept. It is important to economical 

 management, to know exactly the number of worms. This is 

 the best time to count them — mark the number on each leaf as 

 removed and thereafter keep a journal of deaths as correctly as 

 possible. In very large establishments the number of worms is 

 estimated by the weight of the eggs. An ounce of good eggs 

 produces about 35,000. The worms hatched on one day should 

 be kept together and separate from those hatched on any other 

 day, that they may pass through their several changes or moult- 

 ings at nearly the same time. 



Moultings, fyc. — There are several varieties of silk worms. 

 The most common change their skins four different times, viz. 

 on the fourth or fifth day after hatching, on the eighth or ninth, 

 on the thirteenth or fourteenth, and on the twenty-second or 

 twenty-third days. These changes are called moultings, and 

 the intervening times, ages. The fifth or last age continues 

 about twelve days, when they cease to eat and prepare to form 

 the cocoons. Thus 32 days intervene between the hatching 

 and the formation of the cocoon. The several ages, however, 



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