Life-histories 



therefore possible to suffocate insects by covering 

 these holes, a matter to which we shall again refer. 

 These holes may be easily seen in many caterpUlars, 

 as their positions are frequently marked by different 

 coloured spots on the sides of the joints. 



The third important thing to know is the Hfe- 

 history : to discover at what stage the insect is 

 capable of doing damage, and at what period in its 

 life it is most open to the application of methods of 

 repression. For example, it is easier to cut out the 

 egg-bracelets of the lackey-moth during pruning in 

 winter than to destroy all the caterpillars by spray- 

 ing in spring ; it is easier to kill all the caterpillars 

 by waiting irntU they have entered their tents at 

 dusk and then cutting them out than to wait until 

 they are larger grown and attempt to deal with 

 them by hand-picking ; it is easier to deal with the 

 grown caterpillar than to collect the chrysahdes, or 

 to capture the moths. To gain the knowledge neces- 

 sary for effective deahng with individual pests 

 entails the most careful and detailed examination 

 into the habits and life-stories of the pests, and this 

 is still in progress in connection with many of them. 

 Such detailed accounts would take far more space 

 than is available in the present little book, but it is 

 hoped that the plan adopted wiU prove useful in 

 indicating not only general methods, but special 

 methods in particular cases. 



109 



