Microscopical Essays. 



211 



it remains for fome time motionlefs, and then begins to bend, 

 move, and agitate it's body in a very lingular manner, till it has 

 opened the exterior covering, which it pufhes off and removes 

 much in the fame manner as we have defcribed in the preceding 

 article, and yet with fuch dexterity, that the pupa remains fuf- 

 pended by the fame girdle. 



The induftry of thofe that fpin cones, or cafes, in which they 

 inclofe themfelves, in order to prepare for their transformation 

 in fecurity, is more generally known, as it is from one fpecies of 

 thefe that we derive fo many benefits, namely, from the filk- 

 worm. All caterpillars undergo fimilar changes with it, and 

 many in the butterfly ftate greatly exceed it in beauty : but the 

 golden tiflue, in which the filk-worm wraps itfelf, far furpaffes the 

 filky threads of all the other kinds ; they may indeed come forth 

 with a variety of colours, and wings bedecked with gold and fcar- 

 let, yet they are but the beings of a fummer's day ; both their life 

 and beauty quickly vanifh, and leave no remembrance after them ; 

 but the filk-worm leaves behind it fuch beneficial monuments, as 

 at once record the wifdom of their Creator, and his bounty to 

 man. * 



The fubftance of which the filk is formed, is a fine yellow 

 tranfparent gum, contained in two refervoirs that wind about the 

 interlines, and which, when they are unfolded, are about ten 

 inches long; they terminate in two exceeding final 1 orifices near 

 the mouth, through which the filk is drawn, or fpun, to the de- 

 gree of finenefs which it's occafions may require. This apparatus 

 has been compared to the inflrument ufed by the wire- drawers, 



C c 2 and 



* Pjullem on the Culture of Silk. 



