SILK-WORMS. 



its skin four times ; it feeds on the leaves of the mulberry ; at 

 the time of moulting it becomes torpid and does not eat; but after 

 changing its skin, its appetite is doubled. When it is ready to 

 change into a chrysalis, it becomes flaccid and soft, and seeks a 

 proper place to construct its cocoon, in which it encloses itself; 

 the first day is occupied in attaching, in an irregular manner, 

 threads of silk to neighbouring bodies to support it; the second 

 day it begins to multiply these threads so as to envelope itself; 

 and on the third day it is entirely concealed in its cocoon. This 

 nest is formed of a single filament of silk wrapped around the 

 animal, and its turns glued together by a kind of gum. It is 

 estimated that the length of this filament in an ordinary cocoon 

 is nine hundred feet. The form of the cocoon is oval, and its 

 colour either yellow or white. 



26. The bombyx remains in the chrysalis state, in the interior 

 of its cocoon, about twenty days ; and when it has finished its 

 metamorphosis, it disgorges upon a point of its parietes a par- 

 ticular liquid, which softens it. and enables the animal to make a 

 round hole through which it escapes. 



27. This precious caterpillar appears to be originally from the 

 northern part of China, and, about the time of Justinian, was 

 imported into Europe by the Greek missionaries; but it was not 

 until the period of the Crusades that its culture passed from Greece 

 into Italy and Sicily. Some gentlemen who accompanied Charles 

 VIII. into Italy during the war of 1494 introduced these insects 

 into the south of France, as well as the mulberry, a tree without 

 which silk-worms cannot be raised ; but for a long time it attracted 

 very little attention. In the present day, however, this branch 

 of agricultural industry forms one of the chief sources of wealth 

 of southern France; and is yearly becoming of more and more 

 importance in the United States. 



28. To obtain the silk produced by these animals, it is neces- 

 sary to kill them before they pierce the cocoon, and then wind or 

 reel off' the thread or filament of which it is composed ; to unglue 

 it, the cocoons are soaked in warm water; then the filaments of 

 three or four are united into one thread. That part of the cocoon 

 which cannot be reeled in this manner is carded, and constitutes 

 floss-silk. 



29. The mulberry bombyx is not the only species of this genus 

 which yields silk that can be usefully employed; the inhabitants 

 of Madagascar make use of a species, the caterpillars of which live 



126. How does the bombyx escape from its cocoon? 



27. What is the history of the silk-worm ? 



28. How is the silk obtained ? What is floss-silk ? 



29. Is there any other species of Bombyx which produces silk ? 



