SILK-WORM. 275 



itself with silk ; and the remainder of its operations became 

 invisible, though these may be understood from examining 

 the work after it is finished. In order to complete the 

 structure, it must draw out of the gum-bag a more delicate 

 silk, and then wdth a stronger gum bind all the inner threads 

 over one another. 



" Here, then, are three coverings entirely different, 

 which afford a succession of shelter. The outer loose 

 silk, or floss, is for keeping off the rain ; the fine silk in 

 the middle prevents the wind from causing injury ; and the 

 glued silk, which composes the tapestry of the chamber 

 where the insect lodges, repels both air and water, and 

 prevents the intrusion of cold. 



" After building her cocoon, she divests herself of her 

 fourth skin, and is transfoimed into a chrysalis, and subse- 

 quently into a moth {Bombyx mori), when, without saw or 

 centre-bit, she makes her way through the shell, the silk, 

 and the floss ; for the Being who teaches her how to build 

 herself a place of rest, where the delicate limbs of the 

 moth may be formed without interruption, instructs her 

 likewise how to open a passage for escape. 



" The cocoon is like a pigeon's egg, and more pointed 

 at one end than the other ; and it is remarkable that the 

 caterpillar does not interweave its silk towards the pointed 

 end, nor apply its glue there as it does in every other 

 part,* by bending itself all around with great pliantness 

 and agility : what is more, she never fails, when her labour 

 is finished, to fix her head opposite to the pointed extremity. 

 The reason of her taking this position is, that she has 

 purj30sely left this part less strongly cemented, and less 

 exactly closed. She is instinctively conscious that this 

 is to be the passage for the perfect insect which she 

 carries in her bowels, and has therefore the additional 

 precaution never to place this pointed extremity against 

 any substance that might obstruct the moth at the period 

 of its egress. 



" When the caterpillar has exhausted herself to furnish 



* This is denied by recent observers. 



