76 METAMORPHOSES. 



" Shall the poor worm that shocks thy sight, 



"The humblest form in nature's train, 

 " Thus rise in new-born lustre bright, 



" And yet the emblem teach in vain ? 



" Ah ! where were once her golden eyes, 



" Her glittering wings of purple pride? 

 " Concealed beneath a rude disguise, 



" A shapeless mass to earth allied. 



" Like thee the hapless reptile lived, 



" Like thee he toil'd, like thee he spun, 

 "Like thine his closing hour arrived, 



" His labor ceased, his web was done. 



"And shall thou, number'd with the dead, 



"No happier state of being know? 

 "And shall no future morrow shed 



" On thee a beam of brighter glow ? 



"Is this the bound of power divine, 



" To animate an insect frame ? 

 " Or shall not He who moulded thine 



" Wake at his will the vital flame? 



" Go, mortal ! in thy reptile state, 



" Enough to know to thee is given ; 

 " Go, and the joyful truth relate ; 



"Frail child of earth! high heir of heaven!" 



A question here naturally presents itself — Why are insects subject to 

 these changes ? For what end is it that, instead of preserving, like other 

 animals^, the same general form from infancy to old age, they appear at 

 one period under a shape so different from that which they finally assume ; 

 and why should they pass through an intermediate state of torpidity so 

 extraordinary ? I can only answer that such is the will of the Creator, 

 who doubtless had the wisest ends in view, although we are incompetent 

 satisfactorily to discover them. Yet one reason for this conformation may 

 be hazarded. A very important part assigned to insects in the economy 

 of nature, as I shall hereafter show, is that of speedily removing supera- 

 bundant and decaying animal and vegetable matter. For such agents an 

 insatiable voracity is an indispensible qualification, and not less so unusual 

 powers of multiplication. But these faculties are in a great degree incom- 

 patible. An insect occupied in the work of reproduction could not con- 

 tinue its voracious feeding. Its life, therefore, after leaving the egg, is 

 divided into three stages. In the first, as larva, it is in a state of sterility ; 

 Its sole object is the satisfying its insatiable hunger; and, for digesting the 

 masses of food which it consumes, its intestines are almost all stomach. 

 This is usually by much the longest period of its existence. Having now 

 laid up a store of materials for the development of the future perfect 

 insect, it becomes a pupa; and during this inactive period the important 

 process slowly proceeds, uninterrupted by the calls of appetite. At length 

 the perfect insect is disclosed. It now often requires no food at all ; and 



' A few vertebrate animals, viz. frogs, toads, and newts, undergo metamorphoses in some 

 respects analogous to those of insects ; their first form as tadpoles being very different from 

 that which they afterwards assume. These reptiles, too, as well as snakes, cast their skin 

 by an operation somewhat similar to that in larva. There is nothing, however, in their 

 metamorphoses at all resembling the pupa state in insects. (See, however. Von Baer's 

 article on the Analogies of the Transformations of Insects and the Higher Animals in the 

 Annales des Sciences Nat.) According to Mr. J. V. Thompson, both the common barnacles 

 and many Crustacea undergo metamorphoses, but to what extent these changes take place 

 in the latter does not seem clearly ascertained. 



