DEFINITION OF THE TERM INSECT. 9) 
the Trachean and Pulmonary Arachnida as forming one 
class. Whether an animal breathes by gills or trachez, 
has a circulation or not, or has double or single organs 
of sex, is surely as strong a reason for considering those 
so distinguished as belonging to different 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 objection, 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 borrowed by Scaliger 
from Albertus Magnus, neither of whom, in Entomo- 
logy, is an authority to weigh against Aristotle, from 
whom we derive the term Insecta, in Greek Evrowe. 
As Fabricius did not alter Linné’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 Jnsecta: for the sake, therefore, of convenience 
and consistency, that I may, as far as the case will ad- 
mit, adhere to the Horatian maxim 
Servetur ad imum 
Qualis ab incepto processerit et sibi constet, 
