88 HISTORY OF 



three weeks or a month's time, after which it be- 

 gins to feed once more, still in its caterpillar form, 

 but a good deal differing from itself before its 

 change. In a few days' time it seems to sleep 

 again ; and, when it awakes, it again changes its 

 clothing, and continues feeding as before. When 

 it has thus taken a sufficiency of food, and its parts 

 are disposed for assuming the aurelia form, the 

 animal forsakes, for the last time, all food and 

 society, and prepares itself a retreat to defend it 

 from external injuries, while it is- seemingly de- 

 prived of life and motion. 



This retreat is no other than its cone, or ball 

 of silk, which nature has taught it to compose 

 with great art, and within which it buries itself, 

 till it assumes its winged form. This cone or ball 

 is spun from two little longish kinds of bags that 

 lie above the intestines, and are filled with a 

 gummy fluid, of a marigold colour. This is the 

 substance of which the threads are formed ; and 

 the little animal is furnished with a surprising ap- 

 paratus for spinning it to the degree of fineness 

 which its occasions may require. This instru- 

 ment in some measure resembles a wire-drawer's 

 machine, in which gold or silver threads are 

 drawn to any degree of minuteness ; and through 

 this the animal draws its thread with great assi- 

 duity. As every thread proceeds from two gum 

 bags, it is probable that each supplies its own, 

 which, however, are united as they proceed from 

 the animal's body. If we examine the thread 

 with a microscope, it will be found that it is flat- 

 ted on one side, and grooved along its length ; 



