INTRODUCTION. 87 



of the future fly, which is gradually developed by 

 the accretion of new matter ; and its various enve- 

 lopes are thrown off as they successively become su- 

 perficial, till it is fully matured and perfected. When 

 in the state of pupa, the embryo having then advanced 

 another stage towards completion, the parts of the 

 perfect insect are even more easily discerned than 

 in the previous condition ; and for some time before 

 the final change they may even be perceived through 

 the membrane in which they are enclosed. 



Even when viewed in this light, as a series of de- 

 velopments without any absolute change of identity, 

 the metamorphoses of these creatures are sufficiently 

 wonderful to be ranked among the most remarkable 

 and interesting natural operations with which we are 

 acquainted. So striking did they appear to the an- 

 cients, that they regarded the butterfly as affording 

 a most lively and beautiful emblem of the soul ; and 

 according to this idea, the Greeks often used the 

 word Psyche, which properly means the human soul, 

 to signify also a butterfly. With greatly more ac- 

 curate notions of the real nature of these transfer* 

 mations, few modern writers on the subject have 

 failed to notice and dilate upon the general symbo- 

 lical analogy which subsists between them and the 

 changes which the human body is destined to un- 

 dergo. The caterpillar chiefly occupied in pro- 

 viding for its bodily wants and appetites is regard- 

 ed as representing the ordinary condition of human 

 life ; the chrysalis the intermediate state of death ; 



