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the mature condition. Sir J. Lubbock gives a plate which illustrates 

 this in the same manner as Haeckel does with regard to Crustacea ; 

 and this very circumstance will show how difficult it is to jjlace before 

 our readers any fair explanation of the views of the author ; for in 

 many cases he simply jjoints to the woodcut as bearing out his view of 

 the close relationship, and in these pages of course we cannot follow 

 him. He says that the stag-beetle, the dragon-fly, the moth, the bee, 

 the ant, the gnat, and the grasshopjier, although they differ much from 

 each other, being dissimilar in size, form, colour, and in habits of life, 

 have been proved by those naturalists who have followed Savigny's 

 method to be " constructed on one common j)lan." And further, our 

 author shows that other groups, as, for instance, Crustacea and 

 Ai'achnida, are " fundamentally similar." In the author's words, " we 

 find in many of the principal groups of insects, that greatly as they 

 differ from one another in theii* mature condition, when they leave 

 the egg they more nearly resemble the typical insect type, consisting 

 of a head, a three-segmented thorax, with three pairs of legs, and 

 a many-jointed abdomen, often with anal appendages. Now, is there 

 any mature animal which answers to this description ? We need not 

 have been surprised if this type, through which it would appear that 

 insects must have passed so many ages since (for winged Neuroptera 

 had been found in the carboniferous strata), had long ago become 

 extinct. Yet it is not so. The interesting genus Campodea still 

 lives ; it inhabits damp earth, and closely resembles the larva of 

 Chloeon, constituting, indeed, a type which occurs in many orders of 

 insects. It is true that the mouth-parts of Campodea do not resemble 

 either the strongly mandibulate form which prevails among the larvae 

 of Coleoptera, Orthoptera, Xeuroj^tera, Hymenoptera, Lepidoptera, or 

 the suctorial type of the Homoptera and Heteroptera. It is, however, 

 not the less interesting or significant on that accoimt, since, as I have 

 elsewhere* pointed out, its mouth-parts are intermediate between the 

 mandibulate and haustellate types, a fact which seems to me most 

 suggestive." From these observations we gather that the author sup- 

 poses the group of insects, both mandibulate and haustellate, to have 

 arisen from ancestors somewhat resembling the Campodea type ; and 

 hence this form is, as he states, of " remarkable interest, since it is 

 the living representative of a primeval type, from which not only the 

 Collembola and Thysanura, but the other great orders of insects have 

 derived their origin." We think that in regard to the minor question 

 of which particular form the class sprang from — always admitting 

 that they did si)ring from some one form — the author's ideas have 

 more in them than those of Professor Haeckel, though of coiu'se every 

 weight must be given to the distinguished German's opinions. We 

 may sum up the author's opinions expressed fully and clearly in this 

 interesting and well-illustrated little volume, by stating that he 

 believes the insects generally are descended from forms like the present 

 existing genus Campodea ; and finally, that these in their turn have 

 been derived from a type resembling the living genus Lindia. 

 * 'Linnffian Journal,' vol. xi. 



