SILKWORM CULTURE. 



The caterpillars of many moths and of a few butterflies produce silk, 

 but certain of those belonging to the family Bombycidae, or true silk- 

 spinners, particularly Bomhyx {Sericaria) mori^ or the mulberry silk- 

 worm, 3'ield the most and the best silk. The races of Bomhyx inori 

 to-da}'' are the result of domestication and artificial rearing, and the 

 wild tj'pe is uncertain, though most authorities assign the foot of the 

 Himalaya as the cradle of the mulberry silkworm. It has been indus- 

 triall}" cultivated in China from time immemorial, and in Europe since 

 the sixth century. 



THE LIFE OF THE SILKWORM. 



Like all insects of its class, before arriving at the perfect winged 

 state, it exists (1) as a caterpillar or larva, and (2) in a chrysalis state. 



/ 9. 



3 if ^ 6 7 S' 9 10 II 12. 



Fig. 1.— Adult silkworm: 1, head; 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, rings; 11, horn; 13, 3 pairs of articulated 

 legs; 14, 4 pairs of abdominal or false legs; 15, a pair of false legs on the last ring. 



THE LARVA, OR CATERPILLAR. 



The larva (tig. 1) has a cylindrical body composed of 12 rings; each 

 of the tirst three has a pair of jointed legs, and the sixth, seventh, 

 eighth, ninth, and twelfth each bears a pair of false legs, destined 

 later to disappear. 



The black elliptical spots on the side are the orifices for breathing, 

 and are called stigmata or spiracles. 



The head is a small mass covered with a hard scale, and is provided 

 with jaws that move laterally, like the wings of a folding door. The 

 alimentary canal extends throughout the entire length of the bod}^ 



