PREFACE. Vll 



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 fimctions 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, notAvithstanding their characters 

 may otherwise be very distinct. 



Such also was the intention of Gmelin in his edition of the Syslema 

 Naturce. 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, Roesel, 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 wliich 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 interesting 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. 



