A. ZIEGLER ON THE CULTURE OF THE SILK-WORM. 377 



mask is formccl. This is gradually removed, and the insect creeps, 

 not without some exertion, out from its old skin, tliat is glued fast 

 to a twig somewhere about the hindmost feet. The shedding usu- 

 ally takes place four times ; the exceptional cases, however, only 

 three times. The closest attention has to be paid by the silk- 

 worm breeder to the equal setting in of this process. Each breed 

 has therefore to be carefully separated at tlic moment of the creep- 

 ing out of the caterpillars, and all the insects must enjoy an equal 

 share of leaves, of sufficient room, and warmth. 



With proper care and treatment, the sheddings will take place 

 in the following intervals : 1st, on the 5tli day of the age of the 

 caterpillar ; 2d, on the 9th ; 8d, on the 15th ; 4th, on the 22d. On 

 the 82d day of its life it begins to spin. The term of a shedding 

 is usually from two to three days, and shows itself by an increased 

 appetite the day previous, which, must be satisfied by sufficient 

 food. At each renewed process the color of the head of the worm 

 gets lighter. 



After it is over the worms must be fed on twigs sj^read over 

 them. At the same time, they are transferred to the other parts 

 of the crates by putting the twigs to which they cling upon them, 

 and the regular feeding is continued. 



At each shedding, occasion must be taken to classify them ac- 

 cording to their size — this producing a better equality in their 

 functions, and, finally, in their maturity. 



Special signs of a well-performed shedding are a lively appe- 

 tite, quietly remaining in their places, and increasing size of the 

 body. On the contrary, a restless running about on their crates 

 or their margins indicates always, if maturity has not been attain- 

 ed yet, a sickly state of the worms. These, as well as those that 

 have not strength enough to strip their skins entirely off, must 

 be taken out. 



Air, Light, and Warmth. 



Pure air, a warmth regulated to what we shall see hereafter, 

 are, besides the regular feeding, the main points in breeding silk- 

 worms. The atmosphere made impure in the room by the evap- 

 oration of the worms, the leaves, the manure, or other influences, 

 must be removed as soon as possible by frequent airing, taking 

 care, however, that no humid air enters from outside, as well as no 

 strong draught. Especially is this necessary in the latter stage 

 of the life of the worms, and, above all, shortly before and during 

 the spinning-time. 



Fresh bunches of icerimith (sage) are very good for improving 

 the air, being suspended on the windows ; also roses put in the 

 room form an agreeable aroma to the worms. In case the exte- 

 rior air has the same degree as that inside, it is better not to let it 

 enter. Quick-burning fire of dry straw, or vessels with freshly- 

 burned lime placed upon the floor, improve the air. Kitchen salt 



