52 NATURAL ARRANGEMENT OF INSECTS. 



the wading birds, that is, which are of the grallatorial 

 type, are distinguished by the very remarkable difference 

 they present in their summer and winter dress.* Cor- 

 rectly speaking, there are scarcely any birds which 

 assume, at first, the plumage of maturity. The young 

 of both sexes, in the first year, are invariably clothed 

 in the colours of the female ; and should those of the 

 mature male differ greatly from the other sex, the dis- 

 tinction does not begin sooner than after the first moult- 

 ing. The further we recede from the quadrupeds, or, 

 in other words, from the typical perfection of ver- 

 tebrate animals, the greater is the change produced by 

 this surprising process of nature, until, upon coming to 

 the amphibian reptiles, we find animals which, in their 

 young state are fish, and in their adult state frogs. 

 Seeing, then, that Nature has contrived so many modes 

 of performing, or rather modifying, the same process, 

 it becomes absolutely necessary to draw a distinction 

 between ecdysis, or simple moulting, and metamor- 

 phosis, or transformation. The former change is almost 

 exclusively confined to vertebrate animals, while the 

 latter is as strongly characteristic of those which are 

 annulose. Our own views of the difference between 

 ecdysis and metamorphosis are, therefore, as follows : 

 The first is a simple casting off of the old skin, un- 

 accompanied by the developement of any new members, 

 or by any variation of form ; these latter being always 

 the consequence of metamorphosis, or transformation. 



(48.) Of metamorphosis, however, there are various 

 kinds, or modifications ; and these may be arranged 

 under the heads of complete, or perfect, and incomplete, 

 or imperfect. Without entering on the abstruse and 

 ingenious disquisitions that have been written by others 

 on this subject, we shall consider all transformations or 

 metamorphoses as incomplete, where the animal is active 

 in ah 1 its changes. Instances of this are innumerable 

 among the annulose animals ; and, as we have just men- 



* The typical chatterers, or the Ampelidce^ are striking instances of this 

 fact. 



