284 THE SCHOOL OF REAUMUR 



what he could do on copper. His first figure, that of a 

 dragon-fly, was successful ; he went on to engrave three 

 moths, and then without further apprenticeship executed 

 the charming plates of the Polype d'eau douce. 



CHARLES BONNET 

 1720-1793 



Traits d'Inseotologie, ou Observations sur les Puoerons. Par M. Charles 

 Bonnet, de la Sool^te Royale de Londres, &o. A second part, published at 

 the same time, contains Observations sur quelques espfeoes de vers d'eau 

 douce, qui coupfe par moreeaux, deviennent autant d'animaux complets. 

 8vo. Paris, 1745. 



About the year 1745 all well-read naturalists, and 

 many people who were not naturalists at all, were 

 strangely excited about the pucerons or aphids. It 

 became known that a young man named Bonnet had 

 just proved that the aphids produced new generations 

 without fertilisation, and this singular exception to the 

 ordinary course of nature created almost as great a stir 

 as the seminal animalcules of Leeuwenhoek or the polyps 

 of Trembley. The story of the aphids occupies the first 

 volume of the Traite d' Insectologie. Though spaced so 

 widely as to occupy 228 pages, it is not longer than many 

 a review article, and may easily be read through in an 

 evening. It is clear and interesting, devoid of techni- 

 calities, and suited in all ways to readers who are 

 intelligent without being learned. 



A short account of Leeuwenhoek's work on the aphids 

 has already been given {supra, p. 206). Several other 

 naturalists had engaged in the further study of these 

 insects, so common and yet so interesting. Among 

 them was Hyacinthe Cestone (1637-1718), who com- 

 municated his observations to Vallisnieri, by whom they 



