24 CLASS INSECTA. 



born in Autumn, ei?cape the rigours of winter and re-appear 

 in the spring of the following year. 



The species of insects, like those of vegetables, are circum- 

 scribed within geographical limits. Those, for example, of 

 the New World, with the exception of a small number, 

 which are all northern, are essentially peculiar to that quar- 

 ter of the globe. It also produces many particular genera. 

 The ancient continent possesses some in its turn which are 

 unknown in the other. The insects of the south of Europe, 

 of North Africa, and of the western and southern countries 

 of Asia, have many mutual relations. The same is true of 

 those of the Moluccas, and the most eastern islands, those of 

 the South Sea included. Many northern species are to be 

 found in the mountains of the south. Those of Africa differ 

 much from those of the opposite countries of America. The 

 insects of South Asia, proceeding eastward from the 

 Indus or the Sind, as far as the confines of China, have 

 strong traits of inter-resemblance. The intertropical regions, 

 covered with immense forests, whose trees are watered with a 

 superabundant dew, are by far the most rich in insects. In this 

 point of view, those of Brazil and Guiana are the most 

 favoured. 



All the general methods relative to insects are essentially 

 reducible to three. Swammerdam has taken the metamor- 

 phoses as the basis of his system. Linnaeus established his 

 on the presence and absence of wings, their number, their 

 consistence, their superposition, the nature of their surface, 

 and the existence or absence of a sting. Fabi'icius, in his 

 plan, only employed the parts of the mouth. The Crustacea 

 and arachnida, in all these distributions, form a part of the 

 insects, and they even occupy the last place in that of Linne, 

 which has generally been adopted. Brisson, however, sepa- 

 rated them ; and his class of crustacea, which he places before 

 that of the insects, contains all of these animals which have 



