24 MEMOIR OF LATREILLE. 
now become general among naturalists, that this 
was the only way in which the study of natural 
objects could be prosecuted with advantage. " The 
road, it is true," says Latreille himself, * speaking 
in reference to the natural arrangement of insects, 
" had already been traced by great masters, and the 
series of principal groups had been tolerably well 
estabhshed; but they had neglected the study of 
those relations of affinity by which these groups 
are connected ; they had never compared the cha- 
racters of the one with those of the other. Struck 
with this deficiency, I conceived the idea of uniting 
the genera into families, a project which I first car- 
ried into efifect in my ' Precis des Caracteres,' &c. 
That was only a mere sketch, and I again took up 
the subject in a more extensive sense, and accom- 
panied with all the details of which it was suscep- 
tible." But the conception which our author had 
formed, even at the early period of which we speak, 
was a very accurate one ; and although in several 
respects it was afterwards modified, some parts of it 
required nothing more than to be fully developed 
and applied. A pretty close resemblance can be 
traced to the Linnean system ; and the Crustacea, 
Arachnides, and Myriapodes are included, as in the 
latter, among insects. The most important change 
minimi discriminis diligentissima observatio." Intro, ad Hist. 
Nat., 1775, p. 401. 
* Considerations Centrales sur TOrdre Naturel des Animaux 
oomposant les Classes des Crustaces, des Arachnides, et des 
Insectes. Paris 1810, 8vo. 
