INSECT. 



841 



Mr. Newman, in the Memoir already alluded to, 

 has given another and equally ingenious arrangement 

 of insects from their preparatory states ; the names of 

 his groups are, however, like those of Linnreus, 

 founded merely upon the nature of the pupa state ; 

 and therefore cannot be applied as characteristic of 

 th3 general metamorphosis. His arrangement is as 

 ollows : 



Amorpha, in which the penultimate state is pro- 

 vided neither with mouth nor organs of loco- 

 motion ; consequently it neither eats nor moves, 

 neither does it bear any resemblance to the per- 

 fect state. 



1. Lepidoptcra. 2. Diptera. 

 Nccromorpha, in which the penultimate state is pro- 

 vided with mouth and organs of locomotion de- 

 tached from the body, but so enclosed in a case 

 that it can employ neither. The resemblance, 

 therefore, to the perfect insect is very consider- 

 able, excepting in total want of motion. 



3. Hymenoptera. 4. Colcoptera. 

 Isomorpha, in which all the stages are active and 

 voracious, and of a similar form. 



5. Orthoptera. 6. Hemiptera. 

 Anuomorpha, in which appear the amorphous, necro- 

 morphous, and isomorphous characters, together 

 with a typical and distinct character. 



7. Neuroptera. 



The Amorpka, although thus divided into the two 

 orders Lepidoptcra and Diptera, are said to be divisible 

 from the metamorphosis into two distinct sections, 

 separated by the fact of their possessing or not pos- 

 sessing, in the penultimate or quiescent state, the last 

 skin of the antepenultimate or previous state. Those 

 which retain such last cuticle are termed Amorpka 

 dermata, and those which do not retain such skin are 

 termed Amorpha adermata, an evident misnomer, since 

 if they do not retain this last mentioned skin, they 

 still are clothed in their own. But in the following 

 page we are informed that the Amorpha adermata actu- 

 ally " retain two distinct coverings, thus resembling 

 the Amorpha dermata." When, however, we look 

 more strictly at the character of the metamorphosis 

 of these groups, and observe the ill effect which its 

 employment has in reference to the natural distribu 

 tion of insects, we shall at once see that this distribu 

 tion, ingenious as it is (especially with reference t 

 the septenary classification of insects, maintained bj 

 its author), and indeed any distribution of insects from 

 the character of metamorphosis alone, evinces th 

 absolute necessity of recurring to other characters 

 Thus, whilst one division of the Amorpka comprise 

 the Diptera with true coarctate pupa, the other com 

 prises not only all Lepidopterous insects, but ata 

 many Diptcra, which must be more nearly allied t 

 the other Diptera than they are to the Lepidoptera 

 Moreover, even amongst the adermatous Dipten 

 many species exhibit a necromorphous rather than a 

 amorphous appearance ; when, however, we regar< 

 the real character of the coarctate pupa (which corre 

 spends with the Amorpha dermata}, we are at one 

 confirmed that the real character of the dipterou 

 pupa is necromorphous and not amorphous. The pup 

 of the bee is truly necromorphous ; its larva forms, o 

 else is by its parents or their assistants (neuters) en 

 closed in a cell, where it is safely guarded ; so that i 

 has only to cast off its skin and appear in its naked, de 

 fenceless, but yet defended state. But the flesh-fly i 

 differently situated. Its functions in nature are such 



the least waste of time would be to their preju 

 ce. We have accordingly seen that in its first 

 roduction this is amply provided against, although 

 n what certainly appears to be an anomalous manner, 

 see our articles, BLUE-BOTTLE-FLY, and BLOW-FLY. ) 

 3uring its growth as a larva it undergoes no moul- 

 mgs of the skin, which are attended in other insects 

 vith a certain loss of time, and on arriving at its full 

 >rowth the same character is still retained. The 

 kin is not cast, but, with the most admirable foresight 

 n the part of the Great Contriver of both great and 

 mall, becomes an envelope answering all the pur- 

 >oses of a silken cocoon or a waxen cell, and serves 

 or the defence of the defenceless inhabitant enclosed 

 'ithin, and which, when carefully examined, proves to 

 e a truly necromorphous pupa. 



But there are other insects belonging to the 

 necromorphous section, which indisputably prove the 

 eal identity of these apparent differences, and shew 

 he necessity of looking at the subject in the most 

 areneral manner. Thus some coleopterous pupae 

 example the Slaphylinidai), and some hymenopterous 

 mpae (example, the Chalctdidai),K[G as truly mummy- 

 brrned as the lepidopterous pupa, whilst other 

 coleopterous pupae (example, Anthrenus, Attagenus) 

 do not quit the larva skin, and are, therefore, amor- 

 ahous. Again, some necromorphous pupae (example, 

 :he Trichoptera), although inactive during a great 

 part of their remaining in that state, become as active, 

 previous to assuming the perfect state, as any of the 

 isomorpha ; and lastly, if we carefully examine the 

 obtected pupa of a butterfly, we shall at once perceive 

 that the only character which separates it from the 

 necromorphous, or incomplete pupa of a beetle, is, 

 that its lirnbs are laid more compactly upon its breast, 

 each, however, being inclosed in its distinct sheath. 



The preceding considerations appear sufficiently 

 to prove that the pupa state of insects is a distinct 

 state, and that instead of being regarded merely as 

 the matured state of the larva, it would be more 

 correct to regard it as the immature state of the 

 imago. This will be still more evident from a more 

 precise investigation of the form and structure of 

 pupae. 



1 . Of those species which undergo the metamor- 

 phosis inchoata of Latreille, the pupae differ only from 

 the preceding state by an increased size, and occa- 

 sionly an increase in the number of segments. Crabs, 

 spiders, centipedes, lice, spring-tailed insects (Tky- 

 sanurce}, are subject to this kind of metamorphosis, 

 which is so slight that it is impossible to decide 

 whether one of these animals has arrived at its perfect 

 state or not ; and hence, as Fabricius observed in his 

 Philosophia Entomologica, it is probable that many 

 supposed species of spiders, &c., have been formed 

 out of the immature states of these animals. 



But there are some insects belonging in reality 

 to the winged tribes, but forming an exception by 

 being destitute of wings in the perfect state ; such 

 are the bed bugs, many individuals of Vclia, Hy- 

 drometra and Germ, likewise numerous Phasmdas, 

 and other apterous Orthoptera and Hemiptera. 



2. Of those species which undergo the metamor- 

 phosis dimidiata of Latreille, the pupa has been 

 most appropriately termed semi-complete by Lin- 

 naeus, we therefore cannot approve of the alteration 

 of this term to sub-incomplete, proposed by Bur- 

 meister : the pupa being intermediate between the 

 larva, iu which the body is completely apterous, 



