286 NATURAL HISTORY. [CH. XVIl 



which would incapacitate him either to flee or de- 

 fend himsdlf from his foes, he would naturally en- 

 deavour to find some secluded spot into which he 

 might retire in the hour of peril. The larvae of in- 

 sects when preparing for their first metamorphosis 

 seem to act upon a similar principle : they appear 

 to be aware of their defenceless condition ; and that 

 Being who gave them life has instructed them in the 

 best means of preserving this precious gift. Some 

 have been taught to weave for themselves a silken 

 case ; others, ignorant of this art, secrete themselves 

 under ground, and in the kindly shelter of their 

 earthy tomb find that security and rest which are 

 denied tliem elsewhere. Others seek some solitaiy 

 spot far removed from their ordinary haunts, and 

 tiiere suspend themselves beyond the reach of their 

 natural enemies. 



The positions in which they place themselves are 

 extremely various : in one species the suspension is 

 vertical ; in another the head is higher than the tail ; 

 in a third the body is placed in a horizontal position. 

 Some fix themselves by the tail only, with the head 

 hanging down ; others pass a girdle of silk around 

 their bodies, and are thus suspended in a sort of 

 hammock ; while others appear simply glued to the 

 wood or stone to which they are attached. 



When the moment of change approaches, the 

 caterpillar fixes upon some part of a leaf or stem, 

 where it spins a little web; it first lines a small 

 space to which it attaches additional threads, so as 

 to make a little cone, or rather button, projecting 

 downwards : this being finished, it fixes itself to the 

 end of the cone by means of hooks with which its 

 two last feet are furnished ; and in order that its 

 hold may be made firm, a part of the body, impelled 

 by alternate elongations and contractions, is well 

 driven into the meshes of the cone. This being 

 efi"ected, the head of the insect is then permitted to 

 hang downwards. Shortly afterward, however, it is 

 seen to quit this vertical Dosture, and to curve its 



