528 SUPPLEMENT 



the other point, if their number for the fourth year was 

 determined by their number in the year in which they were 

 observed, one might, in following them for four years, deter- 

 mine their number for ever, a thing totally contrary to all 

 observation. It often happens that these insects are very 

 common for several years in succession, and that they are 

 much less so during many other years, without there being 

 any thing like a permanent order in the times of their ap- 

 pearances. A very abundant brood of eggs may be followed 

 by few cock-chafers in the fourth year, if the causes con- 

 nected with the growth and development of the larvae should 

 prove unfavourable. A less abundant oviposition may be 

 followed by a considerable quantity of cock-chafers in the 

 fourth year, if these causes, on the contrary, are very favour- 

 able, if the eggs disclose well and the larvae do not perish. 

 Each female cock-chafer, laying near a hundred eggs," it is 

 easy to conclude that a small number of these insects may 

 nevertheless leave a very numerous posterity. 



Passing over the intervening sub-genera we come to the 

 division Hoplides. The Hopli.e were thus named by Illi- 

 ger, and until his time had been confounded with melolontha. 

 From these last, however, they are very sufficiently distin- 

 guished. 



The Hopliae are small coleoptera, which appear to be 

 peculiar to the western countries of the ancient continent. 

 They are especially found in the hot and temperate parts. 

 They remain tranquilly on the leaves of different vegetables, 

 which they gnaw. Many species appear to prefer those 

 which grow on the banks of streams, rivers, or in humid 

 places. 



The genus Trichius, in the Entomology of Olivier, forms 

 but a single division, the second of the genus cetotiia, from 

 which, in fact, it differs but little in the relation of the mas- 

 ticating organs. It may, however, be distinguished from it 



