SPINNING APPARATUS. 41 



which contract and elongate as the animal moves. 

 It is furnished with sixteen legs, in pairs : three 

 pairs in front, under the first three rings, are 

 covered with a shelly or scaly substance; the 

 other five pairs, called holders, are furnished with 

 little hooks, which assist the insect in climbing. 

 The head is covered with a scaly substance similar 

 to the covering of the fore legs. The mandibles 

 are of great strength, and indented like the teeth 

 of a saw. Beneath the jaw are two small openings, 

 through which the insect draws its silken lines. 

 The substance of which the silk is composed is a 

 fine yellow transparent gum, secreted in two 

 slender vessels, " which are wound, as it were, on 

 two spindles in the stomach ; if unfolded, these 

 vessels would be about ten inches in length." 

 The insect breathes by means of eighteen holes 

 or spiracles, distributed along the body, nine on 

 each side. On each side of the head, near the 

 mouth, are seven small eyes; the two specks 

 higher up on the head, which are generally mis- 

 taken for eyes, are only parts of the skull. 



When the silkworm is ready to spin, it gets 



