^o6 



Marvels of Insect Life. 



do not equal the length of the body. In the full-grown silkworm the weight of 

 the glands equals two-fifths of the Insect's total weight. This is not surprising 

 when we consider the great length of thread that is produced in the weaving of 

 the cocoon. 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 by the weight of the cocoons. In agreement with this result, it is found 

 that a silkworm which is to develop into a female moth has larger silk-glands than 



one that is to become a male 

 moth. 



The history of the domes- 

 tication of the silkworm, 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 in- 

 troduction of the Insect into 

 Europe may be spoken of as 

 recent ; and it is probable 

 that the silkworm is a native 

 of China, though some con- 

 sider it to have originated as 

 a wild species in Bengal. 

 Silk tissues reached Europe 

 from Asia long before any- 

 thing certain was known as 

 to their origin, " some sup- 

 posing," Kirby and Spence 

 tell us, "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 manufacturing 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-molh, 

 with which, concealing them in hollow canes, they hastened to Constantinople, where 

 they speedily multiplied, and were subsequently introduced into Italy, of which 



Pholo by] [E. Step, F.L.S. 



Four-spotted Dragon-Fly. 

 One of our larger native species, of the fiat-bodied section, whose wings are inarkid 

 at the base with a blotch of brown, and the hind-body coated with a bluish powder. 



