302 



INSECTS. 



vy dews forbid this method. A room is preferred with a fouth afpe6tj the 

 windows well glazed, the Walls well built, the floor exceeding clofe, 



. fo as to admit neither air nor infecls. In the middle are four pillars 

 forming a pretty large fquare. Between thefe are different (lories made 



' with ozier hurdles ; and under each hurdle a floor, with an upright bor- 



~ der round, hung on pulleys, placed or taken down at pleafure. When 

 the worms are hatched, fome tender mulberry leaves are placed in the 

 paper box in which the eggs were, and which is large enough to hold a 

 number. When they have acquired ftrength, they muft be diftributed 

 on beds of mulberry leaves in the different ftories. They have a thread 

 by which they can fufpend themfelves, to prevent any fiiock by a fall. 

 Frefh leaves mud be brought every morning, and ftrewed very gently and 

 equally over them; the filkworms will forfake the old leaves. The 

 leaves muft be gathered when the weather is dry, and kept dry, if a ftore 

 be neceffary. To give them air, open their chamber windows, when 

 the fun fhines warmeft. 



The worm, when it burfts the fhell, is extremely fmall, and black ; but 

 the head more fhining black than the body : fome days after, they begin 

 to turn whitifh, or grey. The infeft throws off its fkin, and appears clothed 

 anew feveral times. When ready to affume the aurelia form, the animal for- 

 fakes, for the laft time, all food and fociety, and prepares its cone, or ball 

 of filk, which is fpun from two little longifh kinds of bags that lie above 

 the inteftines, and are filled with a gummy fluid, of a marigold colour. The 

 little animal is furnifiied with a fqrprifing apparatus for fpinning it to every 

 degree of finenefs, fomewhat like a wire-drawer's machine. The threads 

 proceed from two gum bags, each fupplying its own. The thread is flatted 

 on one fide, and grooved along its length ; feeming as if doubled juft on 



- leaving the body, and that the two threads flick to each other by their 

 gummy quality. Previous to fpinning, the filkworm feeks a convenient 

 place to ered: its cell. When it has found a leaf or chink to its purpofe, it 

 wreathes its head in every direftion, and faftens its thread on every fide. 

 Though its firfl: effays feem confu fed, yet they are not without defign : the 

 (irft threads being thrown at random, to ferve as a fliekcr againft rain ; for 

 nature having appointed the animal to work on trees in the open air, its 

 habits remain, though it is brought up in a warm apartment. It is com- 

 pofed externally of a kind of rough cotton-like fubftance, called flofs ; 

 within the thread is more ciiftinft and even ; and next the aurelia, the 

 apartment feems lined with a paper-like fubftance, but of ftronger confift- 

 ence The thread lies very irregularly, and winds oft' now from one fide 



fo 



