OF NATURAL HISTORY. 399 



Ijefore their metamorphofis. The belt is loofe, and allows the chry- 

 falis to perform its flow and feeble movements. 



The whole moth-kind, as well as the filk-worm, immediately be- 

 fore their transformation into the chryfalis ftate, cover their bodies 

 with a cod or clue of filk, though the nature of the filk, and their 

 mode of fpinning, are very different. The cods of the filk-worm 

 are compofed of pure filk. Their figure is geneially oval, which 

 neceflarily refults from that of the animal's body upon which they 

 are moulded. When fpinning, they twift their bodies into the form 

 of an S. The cod is produced by numberlefs circumvolutions and 

 zigzags of the fame thread. The filk is fpun by an inftrument 

 fituated near the mouth of the infed. The filky matter, before it 

 is manufadured by the fpinning inftrument, appears under the form 

 of a gum alnioft liquid, which is contained in two large refervoirs 

 contorted like the Inteftlnes of larger animals, and which terminate 

 at the fpinning inftrument by two parallel and flender conduits. 

 Each conduit furniflies matter for one thread. The fpinning In- 

 ftrument, as Is evident when viewed by the microfcope, unites the 

 two threads into one. Thus a thread of filk, which has the appear- 

 ance of being fingle, is in reality double, and fpun with great dexte- 

 rity. Some writers, who delight in the marvellous, afcribe forefight 

 to the filk-worm in fpinning its cod. The filk-worm, it muft be 

 acknowledged, ads as if it forefaw the approaching event. But the 

 truth is, that, when the animal has acquired its full growth, Its re- 

 fervoirs of filk are completely filled. It then feems to be ftrongly 

 ftimulated to evacuate this glutinous matter. Its different move- 

 ments and attitudes, while difcharging the filk, produce thofe oval 

 bundles which clothe and ornament vaft numbers of the human 

 fpecles. 



P p 3 Another 



