AGRICULTURAL INDUSTRIES. 195 



top side with tender mulberry leaves. The worms that have 

 crawled out, get to the food through the holes in the paper, and 

 can easily be carried off with it the hurdles. 



If the breeding is carefully conducted, the bed must be cleaned 

 daily, except during the times of casting, The cleaning is done 

 before a fresh supply of food is given, and, as a rule, in the following 

 way. Above the bed is stretched a thin net (Ami) of hemp-yarn. 

 On this fresh leaves are laid, to which the worms crawl over. 

 Then the straw mat beneath, with its remnants of food, droppings, 

 and possibly dead worms, is withdrawn and cleaned, or replaced 

 directly by another with fresh food. I also saw people carry with 

 their fingers to the new bed the inert worms which had remained 

 behind ; but it is better to place them on special hurdles and tend 

 them there, for their languor is often only the first sign of sickness, 

 and it is therefore important that they should be separated from 

 the healthy worms as soon as possible. And it is a point in careful 

 breeding to keep together worms of the same age and condition, 

 which go through their castings simultaneously, and finally spin 

 themselves in and go into the chrysalis stage at pretty much the 

 same time. On this account worms that are hatched a day earlier 

 or later than the great majority, are separated from these and 

 tended on special beds. 



On the other hand, it often happens that a breeder begins with a 

 second or even third series of worms a week or two after the breed- 

 ing has begun, if he still has seed and plenty of food at hand. 

 After the third, and especially after the fourth casting, the worms 

 grow rapidly, and must be separated and put on more beds, so as 

 not to lie too close together, or perhaps even on top of one another. 

 This is best done at the last bed-cleaning before the castings, so that 

 after the third casting there shall be 80 to 100 worms to a square 

 foot of bed. When the change of skin (Jap. Neoki-tsuru ; French 

 mue) is drawing near, the worm stops feeding, and becomes some- 

 what brighter and smoother, and translucent ; its head swells ; it 

 raises itself up with its head on high like a sphinx, in this position 

 falling into a sick lethargic state, a sleep in which it must not be 

 disturbed till the casting is over. When its development is healthy 

 and normal, this lasts one day. Then the worm turns to its food 

 with new and strengthened appetite, its capacity being much in- 

 creased. With the Japanese breeds the first and fifth period of age 

 are the longest, each of them lasting eight days, and each of the 

 others averaging six days. Of 300 kg. of food, which 20,000 worms 

 require for their development, more than three-fourths is devoured 

 between the fourth casting and going into the chrysalis state. 

 Their growth and increase in weight correspond to this astonishing 

 requirement of food. Nitrogen alone has formed 14 per cent, of 

 a worm's weight. 



The following table will give some informativon as to the relative 

 weight of the worm at the end of its separate periods of existence, 

 and also of its transformations. 



