158 THE NATURE-STUDY REVIEW [1, 4. julv 1905 



the molting process, manner of taking food and amount consumed 

 and the external appearance at different ages. During the fourth 

 week the amount of food taken may be quite accurately reckoned 

 by cutting the leaves into pieces an inch square and keeping a 

 record of the number of squares eaten. Other data furnished by 

 the United States Department of Agriculture will enable the 

 pupils to work out the number of leaves required to make a silk 

 dress. Two dozen worms will consume about one pound of leaves 

 during the five days succeeding the last molt. Interesting results 

 may be obtained by rearing some worms in a cool room and with 

 a limited amount of food. Care should be exercised that accurate 

 records of observations are made by the pupils daily. 



Eiq-ht or nine davs after the last molt, when the larvae become 

 restless and wander about the box, two or three small bushy 

 twigs should be supplied to afford fastenings for the cocoons, as 

 those spun along the sides of the box are sometimes imperfect. 

 In from fifteen to twenty days after the formation of the cocoon, 

 the adult moth comes forth if the temperature has been about 

 seventv degrees. Cold lengthens the period greatly. One 

 cocoon should be cut open the third day after the spinning was 

 begun ; another, on the fifth ; and another, on the thirteenth day, 

 so that the changes in the inmate may be studied. These indi- 

 viduals, even when removed from the cocoons, will in some cases 

 give rise to moths. 



Within a few hours after the moths emerge, the female will 

 begin to deposit its batch of five or six hundred eggs, which of 

 course will not be fertile unless union with a male has occurred 

 previously. It is therefore important that a male moth, easily 

 recognized by its smaller abdomen, should be placed near a female 

 within a few hours after breaking from the cocoon if the eggs 

 are to be used the following year. Fertile eggs will become 

 grayish a few davs after being laid, while others remain white. 

 The moths take no food and die within a week or two after birth, 

 but the eggs may be preserved for hatching the following spring 

 by keeping them in a vermin-proof box placed in a cool dry cellar 

 or other room having a temperature not above sixty degrees and 

 not below the freezing point. A temperature as high as seventy 

 degrees before Christmas will do no harm. 



A few days before the moth issues the fiber forming the cocoon 

 may be uncoiled on a spool or pencil by removing the loose outer 



