DEFINITION OF THE TERM INSECT. 21 



the Trachean and Pulmonary Arachnida as forming one 

 class. Whether an animal breathes by gills or tracheae, 

 or has a circulation or not, is surely as strong a reason 

 for considering those so distinguished as belonging to dif- 

 ferent classes, as the taking of their food by suction or by 

 manducation is, for separating others to the full as much 

 or more nearly related as to their external structure. 

 But of this more hereafter. I cannot help, as a last ob- 

 jection, lamenting that our learned author has rejected 

 from his system a term consecrated from the most remote 

 antiquity, and which, even admitting his arrangement, 

 might have been substituted for Annulosa, a name bor- 

 rowed by Scaliger from Albertus Magnus, neither of 

 whom, in Entomology, is an authority to weigh against 

 Aristotle, from whom we derive the term Insecta, in 

 Greek Evropct. 



As Fabricius did not alter Linne's class Insecta, but 

 merely broke up his orders into new ones, which he 

 named classes, I shall give you a detail of the alterations 

 he introduced into the science in a future letter. 



Having stated what my predecessors have done in 

 classification, I shall next proceed to lay before you my 

 own sentiments as to-^-What is an insect. Since our 

 correspondence commenced, the Arachnida, principally 

 on account of their internal organization, have been ex- 

 cluded from bearing that name, carrying with them, as 

 we have seen, several tribes, which as yet have not 

 been discovered to differ materially in that respect from 

 the present Insecta : for the sake, therefore, of conve- 

 nience and consistencjr, that I may, as far as the case 

 will admit, adhere to the Horatian maxim 



Servetur ad imum 



Qualis ab incepto proeesserit et sibi constet, 



