8 INSECT ARTIZANS AND THEIR WORK 



The average length of silk wound off from a single 

 cocoon is 1,526 feet; but there is a difference 

 between the produce from a cocoon containing a 

 female chrysalis and one containing a male sufficient 

 to enable the silk-farmers to sort out the sexes hy 

 the weight of the cocoons. In agreement with this 

 result it is found that a Silkworm that is to develop 

 into a female moth has larger silk-glands than one 

 that is to become a male moth. 



The history of the domestication of the Silk- 

 worm, like that of the Honey-bee, extends so far 

 back that its beginnings are hidden in the mists 

 of antiquity. Silk is known to have been in general 

 use among the Chinese at a period compared with 

 which the introduction of the insect to Europe 

 may be spoken of as recent. Silk tissue reached 

 Europe from Asia long before anything certain 

 was known here as to its origin, " some supposing 

 it to be the entrails of a spider-like insect with 

 eight legs, which was fed for four years upon a 

 kind of paste, and then with the leaves of the green 

 willow, until it burst with fat ; others that it was 

 the produce of a worm which built clay nests and 

 collected wax ; Aristotle, with more truth, that 

 it was unwound from the pupa of a large horned 

 caterpillar. 



" Nor was the mode of producing and manu- 

 facturing this precious material known to Europe 

 until long after the Christian era, being first 

 learnt about the year 550, by two monks, who 

 procured in India the eggs of the Silkworm moth, 



