PREFACE. 
vii 
same consistence. The form and uses of the organs of manducation 
are viewed in a secondary light. My series of Orders relative to the 
winged Insects is, consequently, nearly similar to that of Linnaeus. 
Fabricius, Cuvier, Lamarck, Clairville and Dumeril, considering 
the difference of the functions of the parts of the mouth of primary 
consequence, have arranged those divisions otherwise. 
In accordance with the plan of M. Cuvier, I have reduced the num- 
ber of families which I established in my previous works, and have 
converted into subgenera the numerous divisions that have been 
made of the genera of Linnaeus, notwithstanding their characters 
may otherwise be very distinct. 
Such also was the intention of Gmelin in his edition of the Systema 
Natures. This method is simple, historical and convenient, as it 
enables the student to proportion his instruction to his age, his capa- 
city, or to the end he has in view. 
All my groups are founded on a comparative examination of all 
the parts of the animals I wish to describe, and on the observation of 
their habits. Most Naturalists stray from the natural system by 
being too exclusive in their considerations. To the facts collected 
by Reaumur, Rcesel, De Geer, Bonnet, the Hubers, &c., respecting 
the instinct of Insects, I have added several ascertained by myself, 
some of which were hitherto unknown. M. Cuvier has added to 
them an extract of his anatomical observations * ; he has even devoted 
himself to fresh researches, among which I will mention those whose 
object was the organization of the Limuli, a very singular genus of 
the Crustacea. 
Being necessarily restricted in the description of species, I have 
always selected for that purpose the most intei’esting and common 
ones, and particularly those mentioned by M. Cuvier in his Tableau 
Elementaire de I’Histoire Naturelle des Animaux. 
LATREILLE. 
* Those added to the present edition are from Messrs. L^on Dufour, Marcel de 
Serres, Straus, Audouin and Milne Edwards. 
