FOOD OF THE SILKWORM. 1 1 



The laying, consisting of 300 to 700 eggs, is generally completed in 

 three day-. 70 to 80 per cent being deposited the first day. 20 to 30 per 



cent the second day. and a few the third day. The mother moth 

 dies six to twelve days later, her death being usually preceded by that 

 of the male. Death occurs more or less speedily, according to the 

 robustness of the moth, the temperature, and the tranquillity in which 

 it has been left. 



Thus iu about sixty-five day- the silkworm has completed it- cycle 

 of existence, its three periods being thirty to forty days in a larval 

 state, rifteen to twenty days as a chrysalis, and eight to twenty days 

 as a moth or perfect insect. 



The rapid development of the silkworm and its marvelous transfor- 

 mations indicate extraordinary power and very active functions. It- 

 respiration is almost equal to that of the frog and of certain large 

 bird.-, which is equivalent to saying that it must be always surrounded 

 by plenty of pure air. 



THE FOOD OF THE SILKWORM. 



The leaf of the white mulberry- is the natural and the best food for 

 the silkworm. There are many varieties of the white mulberry — some 

 much better adapted than others to commercial silk culture, and some 

 better suited to certain localities. 



The race, the size of the worms, the variety and age of the mulberry, 

 the nutritive quality of the leaf, the year, the season, and the climate 

 make the requisite quantity of leaf very variable. The following is 

 given as a basis of calculation, all circumstances being considered, and 

 the leaves not being cleaned: For the larvae hatched from 1 ounce of 

 egg-, during the first age 11 pounds of leaves: during tin- second age. 

 26 to 33 pounds: during the third age. ss ^ to 14."» pound-: during the 

 fourth age 264 to 352 pounds: during the fifth age. L, 540 to 1,760 

 pounds; or about 2,200 pounds in all. of which one-half is consumed 

 in the last six or seven days of the tifth age. 



The age of the leaf -hould be relative to that of the worm. Young 

 worms fed on old leaf, or old worm- fed on young leaf, are apt to 

 become diseased, and even though they may not die. will scarcely 

 mount or will spin indifferently. A change oi leaf, too. -hould. if p ■- 

 sible. be avoided, or made gradually. Fresh leaf only -hould bo used, 

 and never when wet with dew or heated, or before it has in a measure 

 acquired the temperature of the room in which the worms are being 

 reared. It -hould be gathered early in the morning or in the evening 

 and should not be bruised or torn, nor should the baskets or apron- used 

 to carry it be the same which are used to remove litter. To avoid 

 fermentation the leaves nm-t be spread out in a cellar or cool, dark- 



For complete information regarding the mulberry, see Bulletin No. 34, Bureau of 

 I'lant Industry, I', s Department of Agriculture. 



