METAMORPHOSES. G7 



sect m form, but are equally capable with it of eatirig 

 and moving. As these insects, however, cast their skins 

 at stated periods, and undergo changes, though slight, 

 in their external and internal conformation, they are re- 

 garded 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 per- 

 fect insect, and were called by Linne complete pupae; 

 and secondly, those of the Linnean order Hemiptera^ 

 which resemble the perfect insect, except in having only 

 the rudiments of wings, and to which the name of semi- 

 complete pupae was applied b}' Linne, and that of semi- 

 nymphs by some other authors a . There is still a fifth 

 kind of pupae, which are not, as in other instances, ex* 

 eluded from the skin of the larva, but remain concealed 

 under it, and were hence called by Linne coarctatc pupae. 

 These, which are peculiar to flies and some other dipte- 

 rous genera, may be termed cased^nymphs b . 

 - When, therefore, we employ the term pupa, we may 

 refer indifferently to the third state of any insect, the 

 particular order being indicated by the context, or an 

 explanatory epithet. The terms chrysalis, (dropping aw- 

 relia, 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, 

 silicle, &c. 



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

 skin of the larva, considerably altered in form and tex- 

 * Plate XVI. Fig. 4. 5. b Plate XVII. Fig. 1-4. 



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