INTKODUCTOEY LETTER. 



7 



caves ' ; while not a few are covered with branching spines, 

 which fancy may form into a forest of trees. ^ 



What numbers vie with the charming offspring of Flora 

 in various beauties ! some in the delicacy and variety of their 

 colours, colours not like those of flowers evanescent and 

 fugitive, but fixed and durable, surviving their subject, and 

 adorning it as much after death as they did when it was 

 alive ; others, again, in the veining and texture of their 

 icings; and others in the rich cottony down that clothes 

 them. To such perfection, indeed, has nature in them 

 carried her mimetic art, that you would declare, upon be- 

 holding some insects, that they had robbed the trees of their 

 leaves to form for themselves artificial wings, so exactly do 

 they resemble them in their form, substance, and vascular 

 structure ; some representing green leaves, and others those 

 that are dry and withered.^ Nay, sometimes this mimicry 

 is so exquisite, that you would mistake the whole insect for 

 a portion of the branching spray of a tree.* ISo mean beauty 

 in some plants arises from the fluting and punctuation of 

 their stems and leaves, and a similar ornament conspicuously 

 distinguishes numerous insects, which also imitate with mul- 

 tiform variety, as may particularly be seen in the caterpillars 

 of many species of certain tribes of butterflies (^NymphalidcB), 

 the spines and prickles which are given as a Noli me tangere 

 armour to several vegetable productions. 



In fishes the lucid scales, of varied hue, that cover and defend 

 them, are universally admired, and esteemed their peculiar 

 ornament ; but place a butterfly's wing under a microscope, 

 that avenue to unseen glories in new worlds, and you will 

 discover that nature has endowed the most numerous of the 

 insect tribes with the same privilege, multiplying in them the 

 forms ^, and diversifying the colouring of this kind of clothing 

 beyond all parallel. The rich and velvet tints of the plumage 

 of birds are not superior to what the curious observer may 



1 Many of the Scarahccidce, Dynastidcc, &c. 



2 Many caterpillars of Butterflies. (Merian, Surinam, t. xxii. xxv. &c.)and of 

 Saivflies. (Reaum. v. t. xii. /. 7, 8 — 14.) 



3 Various species of the families Gryllidcs. and Mantidce. 



4 Many species of PJiasmidce. 



5 De Geer, I. t. 3. /. 1—34, &c. Audouin, Hist. Pyr. de la Vigne, PI. 3. 



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