STATES OF INSECTS. 193 



hence it follows, that the hairs have their place and take 

 their whole growth between the new skin and the old a . 

 Whether the spines, simple or compound, lately described 

 to you, that arm some larvae are similarly circumstanced, 

 seems not as yet to have been ascertained ; but as the 

 spinous ones of certain Tenthredines L. and Lepidoptera 

 at their last moult have no spines, the presumption is, 

 that, whether incased or not, they are mere appendages 

 of the skin on which they appear. A new set of hairs, 

 therefore, and probably of spines in spinous larvae, ac- 

 companying each skin, and these varying very much in 

 size, composition, &c. though a new membrane may be 

 admitted to be formed from an action in the rete mucosum 

 without a pre-existent germe of it, it seems not easy to 

 conceive how these hairs and spines can spring up and 

 grow there, each according to a certain law, without ex- 

 isting previously as a kind of carculum or punctum saliens; 

 and that the germes of the tubercles, in which the hairs 

 are so generally planted, according to a certain arrange- 

 ment and in a given number, should also pre-exist, seems 

 most consonant to reason. These and the several skins may 

 all co-exist in their primordial germes, and remain be- 

 yond the discovery of our highest powers of assisted vi- 

 sion, till a certain period when they may first enter the 

 range of the microscope-aided eye. It does not therefore 

 follow, because these primordza semina rerum are not 

 discoverable, that therefore they may not exist. Our 

 faculties and organs are too limited and of too little power 

 to enable us to see the essences of being:. 



Upon the supposition that the hypothesis of Swam- 



a N. Diet. d'Hist, Nat. vi. 290. 

 VOL. Ill, O 



