xiv THE AUTHOR'S PREFACES. 



teresting, claimed to have the preference. Among the Invertehrata, I have had more 

 particularly to study the naked moUusks and the great zoophytes ; but the innumerable 

 variations of the external forms of shells and corals, the microscopic animals, and the 

 other families which perform a less obvious office in the economy of nature, or whose 

 organization affords but little room for the exercise of the scalpel, did not require to 

 be treated with the same detail. Independently of which, so far as the shells and 

 corals are concerned, I could depend on a work just published by M. de Lamarck, in 

 which will be found all that the most ardent desire for information can require. 



With respect to insects, so interesting by their external forms, their organization, 

 habits, and by their influence on all living nature, I have had the good fortune to find as- 

 sistance which, in rendering my work infinitely more perfect than it could have been had 

 it emanated solely from my pen, has, at the same time, greatly accelerated its publica- 

 tion. My colleague and friend, M. Latreille, who has studied these animals more 

 profoundly than any other man in Europe, has kindly consented to give, in a single 

 volume, and nearly in the order adopted for the other parts, a summary of his immense 

 researches, and an abridged description of those innumerable genera which entomolo- 

 gists are continually establishing. 



As for the rest, if in some instances I have given less extent to the exposition of 

 eub-genera and species, this inequality has not occurred in aught that concerns the 

 superior divisions and the indications of affinities, which I have every where founded on 

 equally solid bases, established by equally assiduous researches. 



I have examined, one by one, all the species of which I could procure specimens ; I 

 have approximated those which merely differed from each other in size, colour, or in 

 the number of some less important parts, and have forme-d them into what I designate 



a sub-genus. 



Whenever it was possible, I have dissected at least one species of each sub-genus ; 

 and if those be excepted to which the scalpel cannot be applied, there exists in my 

 work but very few groups of this degree, of which I cannot produce seme considerable 

 portion of the organs. 



After having determined the names of the species which I had examined, and which 

 had previously been either well figured or well described, I placed in the same sub- 

 genera thase which I had not seen, but whose exact figures, or descriptions, sufficiently 

 precise to leave no doubt of their natural relations, I found in authors ; but I have 

 passed over in silence that great number of vague indications, on which, in my opinion, 

 naturalii'ts have been too eager to establish species, the adoption'of which has mainly 

 contributed to introduce into the catalogue of beings, that confusion which deprives it 

 of so much of its utility. 



I could have added, almost every where, a vast number of new species ; but as I 

 could not refer to figures, it would have been incumbent on me to extend their descrip- 

 tions beyond what space permitted : I have, therefore, preferred depriving my work of 

 this ornament, and have only indicated those, the peculiar conformation of which gives 

 rise to new sub-genera. 



^ My sub-gcncra once cstablislied on positive relations, and composed of well-authen- 

 ticated species, it remained only to construct this great scaffolding of genera, tribes, 

 families, orders, classes, and primary divisions, which constitute the entire animal 

 kingdom. , 



