METAMORPHOSES. 35 



external and internal conformation, they are regarded also as being subject 

 to metamorphoses. These pupae may be subdivided into two classes ; first, 

 those comprised, with some exceptions, under the Linnean Aptera, which 

 in almost every respect resemble the perfect insect, and were called by 

 Linne complete pupae ; and, secondly, those of the Linnean order Hemi- 

 ptera, which resemble the perfect insect, except in having only the rudi- 

 ments of wings, and to which the name of semi-complete pupae was 

 applied by Linne, and that of semi-nymphs by some other authors. There 

 is still a fifth kind of pupae, which are not, as in other instances, excluded 

 from the skin of the larva, but remain concealed under it, and were hence 

 called by Linne coarctate pupas. These, which are peculiar to flies and 

 some other dipterous genera, may be termed cased-nymphs. 



When, therefore, we employ the term pupa, we refer indifferently to the 

 third state of any insect, the particular order being indicated by the con- 

 text, or an explanatory epithet. The terms chrysalis (dropping aurelia, 

 which is superfluous), nymph, semi-nymph, and cased-nymph, on the other 

 hand, definitely pointing out the particular sort of pupa meant : just as in 

 Botany, the common term pericarp applies to all seed-vessels, the several 

 kinds being designated by the names of capsule, silicic, &c. 



The envelope of cased-nymphs, which is formed of the skin of the larva, 

 considerably altered in form and texture, may be conveniently called the 

 puparium: but to the artificial coverings of different kinds, whether of silk, 

 wood, or earth, &c., which many insects of the other orders fabricate for 

 themselves previously to assuming the pupa state, and which have been 

 called by different writers, pods, cods, husks, and beans, I shall continue the 

 more definite French term cocon, anglicized into cocoon. 



After remaining a shorter or longer period, some species only a few 

 hours, others months, others one or more years, in the pupa state, the 

 enclosed insect, now become mature in all its parts, bursts the case which 

 enclosed it, quits the pupa, and enters upon the fourth and last state. 



We now see it (unless it be an apterous species) furnished with wings, 

 capable of propagation, and often under a form altogether different from 

 those which it has previously borne a perfect beetle, butterfly, or other 

 insect. This Linne termed the imago state, and the animal that had 

 attained to it the imago ; because, having laid aside its mask, and cast off 

 its swaddling bands, being no longer disguised or confined, or in any respect 

 imperfect, it is now become a true representative or image of its species. 

 This state is in general referred to when an insect is spoken of without the 

 restricting terms larva or pupa. 



Such being the singularity of the transformations of insects, you will not 

 think the ancients were so wholly unprovided with a show of argument as 

 we are accustomed to consider them, for their belief in the possibility of 

 many of the marvellous metamorphoses which their poets recount. Utterly 

 ignorant as they were of modern physiological discoveries, the conversion 

 of a caterpillar into a butterfly must have been a fact sufficient to put to a 

 nonplus all the sceptical oppugners of such transformations. And however 

 we may smile, in this enlightened age, at the inference drawn not two cen- 

 turies ago by Sir Theodore Mayerne, the editor of Mouffet's work on 

 insects, " that if animals are transmuted so may metals 15 ', it was not, in 



i Epist. Dedicat. 

 D 2 



