PREFACE. 
V 
manner in which they are reticulated. It is in fact a union of the 
system of Fabricius with that of Linnaeus perfected. 
The divisions made by our savant in his first order, that of the 
Gnathaptera, are nearly similar to those I had established in a Memoir 
presented to the Societe Philomatique, April, 1795, and in my Precis 
des Caracteres Generiques des Insectes*. 
M. de Lamarck, whose name is so dear to the friends of natural 
science, has ably profited by these various labours. His systematic 
arrangement of the Linnaean Aptera appears to us to be that which 
approaches nearest to the natural order, and, with some modifications 
of which we are about to speak, is the one we have followed. 
I divide the Insects of Linnaeus, with him, into three classes : the 
Crustacea, Arachnides and Insecta; but in the essential characters 
which I assign to them, I abstract all the changes experienced by 
these animals, prior to their adult state. This consideration, although 
natural, and previously employed by De Geer in his arrangement of 
the Aptera, is not classical, inasmuch as it supposes the observation 
of the animal in its difiPerent ages; it is, besides, liable to many 
exceptions f . 
The situation and form of the branchiae, the manner in which the 
head is united to the thorax, and the organs of manducation, have 
furnished me the means of establishing seven orders in the class of 
the Crustacea, all of which appear to me to be natural. I terminate 
it, with M. de Lamarck, by the Branchiopoda, which are a sort of 
Crustacea Arachnides. 
In the following class, that of the Arachnides, I only include the 
species which in the system of Lamarck compose the order of his 
Arachnides pa/pistes, or those which have no antennae. Beyond 
this, the organization of these animals, external as well as internal, 
furnishes us with a simple and rigorous rule that is susceptible of a 
general application. 
* I there divided the Aptera of Linnaeus into seven orders: 1. The Suctoria. 
2. The Thysanoura. 3. The Parasita. 4. The Acephala C Ar actinides pal- 
pistes, Lam.) 5. The Entomostraca. 6. Tlie Crustacea. 7. The Myria- 
PODA. 
-t These considerations, however, have not been overlooked, and I have used them 
advantageously in grouping families, and arranging them in a natural order, as may 
be seen by a reference to the historical sketches which precede the exposition of 
those families. I have even been employed on a work respecting the metamorphosis 
of Insects in general, which has not yet been published (see article “Insectes,” Nouv. 
Diet. d’Hist. Nat. Ed. 2d), but which I have long been maturing, and which I have 
communicated to my friends : I have made use of it in the course of my general 
remarks. 
