26 



The fifth day after the mounting the worms that have not begun to 



spin should be placed in bundles of twigs and covered with straw or 



leaves, or put in a basket of shavings, where they will be forced to spin. 



The temperature during the spinning should be 75° F., and the 



humidity throughout 

 the rearing about 65°. 

 A good practical test 

 of humidity is a saucer 

 of salt; when the salt 

 is moist, reduce the 

 humidity. Carefully 

 avoid disturbing the 

 worms while spinning, 

 and then, as during all 

 the ages, keep the room 

 as quiet as possible. 

 The most scrupulous 

 cleanliness should al- 

 ways be observed, both 



Fig. 11.— Arrangement of spinning places. (Redrawn from Pasteur.) -^j^Jj regard tO the 



quarters and the attendants; to keep from raising dust, wipe the floor 

 with a damp cloth instead of sweeping it. 



PREPARING COCOONS FOR THE MARKET. 



The transformation of the larva into the chrysalis is, according to 

 temperature, completed in from seven to ten days from the time at 

 which the first worm begins to spin. The cocoons are then said to be 

 mature, and this is the best time to gather them. After the removal 

 of the web the cocoons are sorted into three classes: (1) The perfect, 

 (2) the double, and (3) the defective or spoiled. 



In the United States, the absence of near-by markets makes it nec- 

 essary that cocoons be prepared and stored away, sometimes for 

 months or until they can be used. This preparing consists of killing 

 the chrysalis and then drying the cocoon until no moisture remains to 

 cause ferment and mildew and a consequent rotting of the silken thread. 

 The killing of the chrysalis is usually termed "choking" or "stifling." 



If the cocoons are not sold as soon as gathered, the chrysalides 

 should be killed without delay unless they are to be reserved for 

 reproduction; otherwise the moths may pierce the cocoons, rendering 

 them unfit for reeling. Cocoons in which the chrysalides are still 

 alive are usuallj^ termed "green" cocoons. 



The chrysalides are usually killed either by heat or suffocation. The 

 killing of the chrysalis is an important operation and one requiring 

 care and judgment. If some are left alive, the moths will issue, thus 

 rendering the cocoon of little value and staining the adjoining cocoons. 



166 



