80 APPLE LEAVES, APHIS LIONS COCOONS HOW SPUN. 



where it lies, and to these the skins of any dead plant-lice or 

 particles of dirt which may be within reach are affixed, to serve 

 as more convenient points of attachment for the threads which 

 are afterwards spun than what the naked threads would be. In- 

 side of these the. insect lies, with its tail playing around back- 

 wards and forth. At first the skin is so distended and the body 

 so stiff that it can only bend inwards in the form of a semicircle 

 or of a horse-shoe, and the head is thus brought opposite the tail, 

 giving the insect a ludicrous aspect as it lies still, with its eyes 

 gazing fixedly at the tail as if in astonishment at seeing it fly 

 around in such a singular manner. The tail at this time reaches 

 around to every part of the half of a sphere, and when one side 

 has become sufficiently filled with threads, the body moves along 

 to give it acces to another side, the insect thus lying at one time 

 upon its side or its back, and at another time standing as it were 

 upon its head. Occasionally, as if tired with its cramped position 

 it straightens out somewhat, thus putting the threads upon the 

 stretch and moulding the sides of the cavity in which it lies into 

 a smooth and even surface. As so much matter is given out from 

 its body to form the threads of the cocoon, the skin ceases to be 

 distended as it was at first, the body shrinks and becomes more 

 flexile, and as the cavity in which it lies becomes more and more 

 contracted in size by the threads which the tail is constantly add- 

 ing on every side, the insect is drawn together into a smaller 

 space and becomes coiled into the form of a ball, the head being 

 pressed down upon the breast, with the tail directly over it briskly 

 continuing its work in the small vacant space which here remains. 

 The feet are now so cramped that they are incapable of turning 

 the body around as at first, and it now only moves along slightly 

 by a vermicular motion often repeated. The threads have now 

 become so numerous and close that finally no open meshes are 

 left between them-, and thus a small ball of paper-like texture is 

 formed in the centre of the cocoon, within which the insect is 

 entirely hid from view, tightly bandaged like the feet of a Chinese 

 lady and compressed to a quarter of its previous size. This is 

 a most remarkable circumstance in the history of these insects — 

 that the larvse contract and compress themselves into cocoons of 

 scarcely one-fourth their size, and from these cocoons come flies 



