72 INTRODUCTION. 



The same era gave birth to other entomologists, whose 

 works mvist be cited with praise — Rosel, Schaffer, Frisch, all 

 of whom have figured and described many insects. Bonnet, 

 whose researches upon the habits and generation of Aphides 

 are of the greatest interest, not only with respect to the 

 natural history of these animals, but also to physiology in 

 general ; Lyonnet, to whose incomparable anatomical details 

 upon the Cossus, I shall have occasion repeatedly to refer ; 

 Fabricius, also the pu])il of Linnaeus, by the vast number of 

 new species of insects which he described, and the pains 

 which he took in bringing to perfection a novel system of 

 classification founded upon the structure of the organs of the 

 mouth (that of Liunseus being built upon the structm-e of 

 the wings), has merited the thanks of the entomologist. 



Hitherto we have seen that in the distributions which had 

 been proposed by entomologists, a single organ, or series of 

 organs, had been selected as a key-stone of the system ; the 

 natural consequence of which, as might have been expected, 

 was the constant artificial results to which such distributions 

 were exposed. 



We now arrive, however, at the era of the eclectic system, 

 or that of Latreille, one of the most indefatigable and philo- 

 sophical entomologists that has yet appeared, who, perceiv- 

 ing this difficulty, successfully accomplished the task of 

 remedying it. He did for Entomology, what his compatriot, 

 Barnard de Jussieu, had succeeded in doing for botany. By 

 making use of the various characters which are exhibited by 

 various organs, in various degrees of dev elopement, in various 

 groups of insects, and by neglecting neither the meta- 

 morphotic characteristics (which were the key of Swammer- 

 dam's arrangement), nor the variations in the structure of 

 the wings (upon which the Linna^an system was founded), 

 nor the structure of the mouth (which Fabricius had em- 

 ployed as above stated), he has established amongst insects 



