CHAP. XII.] THE CLASSIFICATION OF PESTS. 129 



their own natural affinities and the various Orders, Families, Genera 

 and Species to which they belong. This method has the great 

 merit of conciseness, because many of the commonest and most 

 important crop-pests attack several different crops and it would 

 entail a large amount of repetition if an account of each of these 

 pests were to be given under the heading of each different crop. 

 The list of crops (pages 240 — 263), however, shows the various 

 insects which attack each and will serve as an index to the insects 

 known to attack such crops and reference to these insects in the 

 systematic list of crop-pests will, it is hoped, facilitate their recog- 

 nition and assist in their control. In order to help still further in 

 this, the succeeding chapters contain brief notes on the more 

 common and important crop-pests classified simply as Caterpillars, 

 Beetles, Grasshoppers, eti . 



