xvi PROOFS, ILLUSTRATIONS, AUTHORITIES, ETC. 



more intimate connection with the mainland and aerial mode of 

 existence indicates a higher degree of development than an aquatic 

 mode of life and between animals living in water, that fluviatile types 

 must rank higher than marine." He goes on " Having already 

 acknowledged the superiority of the sucking insects over the chewing 

 tribes, we cannot fail to perceive that the Neuroptera, which must be 

 considered as the lowest, inasmuch as their body still preserves the 

 elongated form of worms, are aquatic in their larval condition and 

 have even external gills as their respiratory organs during that 

 period. Next Coleoptera, among which also we find aquatic larvae, 

 and a number of terrestrial types ; and highest the Orthoptera, which 

 undergo a less extensive, but entirely terrestrial development, whilst 

 Hymenoptera have a more diversified metamorphosis, and assume 

 even in their larval condition in some of their types, the higher forms 

 which characterise the larvae of Lepidoptera. 



" Among the sucking insects we begin again with various aquatic 

 types or aquatic larval tbrms next rise to Diptera, with other aquatic 

 larval conditions, but a constant aerial mode of life in the perfect 

 state, and finally to the type Lepidoptera, in which all the larvae are 

 terrestrial, and even highly organized in their earliest state in the 

 higher groups." .... 



Few and scattered, we may repeat, as the fossil insects are, it is 

 certainly striking, after M. Agassiz's view of the gradations of the 

 class, to find Arachnida, Coleoptera, and Neuroptera first in the series 

 of rocks, and Lepidoptera not occurring till the Tertiary. Nor is 

 negative evidence here quite despicable, when we see that from the 

 bed of the lias called the Insect Limestone no fewer than twenty 

 families have been taken, and yet among them all none superior to 

 Neuroptera and Coleoptera. 



" The great class of Insects, which furnishes four-fifths of the ex- 

 isting species of the Animal Kingdom, has two chief divisions. In 

 the one (the Ametabola) we have an imperfect, in the other (the 

 Metabola) a perfect metamorphosis ; that is, in the former there is no 

 quiescent pupa state, and the metamorphosis is accompanied by no 

 striking change of form ; in the latter there is an inactive pupa that 

 takes no nourishment, and so great a change of form that only by 

 watching the progress of the metamorphosis can we recognise the 

 pupa and the imago as being the same animal. The Metabola, cor- 

 respond, as it were, to the flowering plants ; the Ametabola to the 

 Cryptogamia. It is well worthy of remark that among plants the 

 Cryptogamic, and among insects the Ametabolous, first appeared 

 upon our earth. The most ancient forests, composed of tree-ferns, 

 club-mosses, and equiseta, were inhabited by Locustce and Slattce t 

 the first of insects. There have not yet been found in the carbo- 

 niferous and triassic rocks any traces of insects that can be with 

 certainty referred to any of the other insect orders. . . . 



" The Ametabolous insects also play the chief part in the Jurassic 

 period. Here they appear as very large Locusts and Dragon-flies, 

 the latter belonging to the JEschnidce (including the Gompki) 



