20 



THE CULTURE OF THE MULBERRY SILKWORM. 



rain}^ for the worms are ^oing to molt in two or three days, and this 

 crisis should not occur in unhealthy conditions. It is always more 

 prudent to change beds on the fourth day, and is, therefore, advised. 

 The space occupied b}^ the worms must be doubled when the change 

 of beds is made. 



The bed on which the leaf and excrement accumulate is, perhaps, 

 the greatest source of danger to the worms. When there is not a free 

 circulation of air, gases are developed which almost always cause fer- 

 mentation, paving the way for future disease. Hence the necessity 

 for frequent change of beds. This is made in various ways. The 

 practice of doing this by hand is to be condenmed because it consumes 

 too much time and is apt to injure the worms. Threadnets (fig. 8) 

 and perforated paper are the best means to employ. The}^ save two- 

 thirds of the hand labor, and 

 thus allow beds to be oftener 

 renewed, which is a most im- 

 portant consideration. In the 

 first age tulle or mosquito net 

 may be employed instead of 

 nets or paper. 



The manner of proceeding is 

 as follows: Place the last meal 

 at night on the nets and extend 

 them over the worms. By 

 morning the worms will have 

 mounted al)OVO the opening in 

 search of fresh leaf. Then lift 

 up the nets, beginning at the 

 top shelf, and place them on 

 clean shelves. Carefully de- 

 tach from the nets any portion 

 of the old bed, and, if the 

 worms are not molting, gather up the few worms that have remained 

 behind, and tenderly place them Avith the others. The change of beds 

 is thus rapidly etfected with the least labor. 



It is very important that the tension of the net be such as to prevent 

 the worms from being crowded together in the middle. 



Perforated paper (fig. 9) is another means often used to effect change 

 of beds; but it does not allow the worms to mount with the same 

 facilit3^ It is also apt to break when the worms become heavy, and 

 in many cases it has to be renewed annually, so, in the end it is no 

 cheaper than nets. 



In changing beds, do not feed the worms that are first taken up until 

 all from the old bed have been removed; then give a general meal, 

 for all the worms boi'n on the same day and forming one class should 



Fir;. 8. — Net used in changing beds. 



