SEPTENARY SYSTEM. 247 



The type of this kind of mouth is found among the Lepi- 

 doptera, where the maxillae are frequently of prodigious length, 

 and convolute ; but as we descend the figure right and left, we 

 find this typical character considerably modified in the Hemip- 

 tera and Diptera, though still abundantly different from any 

 form of mouth existing among the classes below the maxillary 

 line. The position of the classes in the Septenary System is, 

 therefore, in perfect accordance with the Maxillary System as 

 promulged by its originators. 



The third grand system of Entomology is called the Meta- 

 morphotic System. Chronologically, this system intervenes 

 between the Alary and Maxillary Systems. These two systems 

 being founded on the structure of the perfect insect could not 

 be separated. The Metamorphotic System, therefore, though 

 chronologically the second, must here rank as the third. It 

 appears that the merit of the invention of this system is due to 

 Swammerdam ; but the definitions employed by this philoso- 

 pher and his contemporary, our illustrious countryman, Ray, 

 are not sufficiently precise to furnish tests by which to try the 

 value of another system. The line T O E in the diagram sepa- 

 rates the six circumferential classes into those which, in the 

 language of Swammerdam, possessed a complete or an incomplete 

 metamorphosis ; and, it may be stated, that no single item in 

 the systems of Ray and Swammerdam is at variance with the 

 Septenary System, except such untenable divisions as have long 

 been abandoned by universal consent, — such, for instance, as the 

 singular location of portions of the Ichneumonites in separate 

 classes. In this case it becomes necessary to have recourse to 

 more precise and recent definitions. 



It has been seen in the chapter to which I have before 

 alluded, that the differences of transformation divide insects 

 into three very natural groups ; the characters of which are 

 thus defined :— 



1. Amorpha, in which the penultimate state is provided neither with 

 mouth nor organs of locomotion : consequently it neither eats nor 

 moves, nor does it bear any resemblance to the perfect state. 



2. Necromorpha, in which the penultimate state is provided with 

 mouth and organs of locomotion detached from the body, but so 

 enveloped in a case that it cannot employ them. The resemblance, 

 therefore, to the perfect state is very considerable, excepting in 

 the total want of motion. 



