56 



METAMOEPIIOSES. 



the wings, rolled up into a sort of cord, are lodged between 

 the first and second segment of the caterpillar ; that the 

 antennae and trunk are coiled up in front of the head ; and 

 that the legs, however different their form, are actually 

 sheathed in its legs. Malpighi discovered the eggs of the 

 future moth, in the chrysalis of a silkworm only a few days 

 old ^, and Reaumur those of another moth (Hypogymna dispar) 

 even in the caterpillar, and that seven or eight days before 

 its change into the pupa.^ A caterpillar, then, may be 

 regarded as a locomotive egg, having for its embryo the 

 included butterfly, which after a certain period assimilates to 

 itself the animal substances by which it is surrounded ; has 

 its organs gradually developed ; and at length breaks through 

 the shell which encloses it. 



This explanation strips the subject of every thing mi- 

 raculous, yet by no means reduces it to a simple or unin- 

 teresting operation. Our reason is confounded at the re- 

 flection that a larva, at first not thicker than a thread, includes 

 the germs of its own triple, or sometimes octuple, teguments ; 

 the case of a chrysalis, and of a butterfly, all curiously folded 

 in each other ; with an apparatus of vessels for breathing and 

 digesting, of nerves for sensation, and of muscles for moving ; 

 and that these various forms of existence will undergo their 

 successive evolutions, by aid of a few leaves received into its 

 stomach. And still less able are we to comprehend how this 

 organ should at one time be capable of digesting leaves, at 

 another only honey ; how one while a silky fluid should be 

 secreted, at another none; or how organs at one period 

 essential to the existence of the insect should at another 

 be cast off, and the whole system which supported them 

 vanish.^ 



]S[or does this explanation, though it precludes the idea of 

 that resemblance, in every particular, which, at one time, 

 was thought to obtain between the metamorphosis of insects, 



1 De Bomhyce, 29. 



2 Reaum. i. 359. 



3 Dr. Herold {Entwickelungs geschichte der Schmetterlinffe), and other modern 

 physiologists, deny that the germs of the skins of the caterpillar and chrysalis 

 and of the future butterfly exist in the young caterpillar ; but, for reasons assigned 

 in detail in another place (vol. iii. edit. 5. pp. 52 — 62.), the theory of Swammer- 

 dam and Bonnet, as above explained, is here preferred. 



