236 OUR INSECT FRIENDS AND FOES 



these feathered natural foes of the insects that 

 we can ever hope to hold them successfully in 

 check. That a certain amount of good may be 

 done by supplementing the work of these natural 

 enemies of our insect foes is obvious, but to 

 imagine that their services can be successfully 

 replaced entirely by artificial means, except very 

 occasionally under the most favourable conditions 

 and at very great cost, is absurd, and can only 

 lead to disaster. The very number and variety of 

 the so-called insecticides, of which highly im- 

 aginative advertisements crowd the columns of 

 the agricultural and horticultural papers, only 

 serve to testify their own worthlessness and the 

 futility of artificial methods unaided by natural 

 checks. 



How, then, can we best help Nature to combat 

 these insect ravagers of our crops? First by 

 encouraging their natural foes, and secondly by 

 striving to become familiar with the lives and 

 habits of the insects, so that we may know when 

 most successfully to apply such artificial means 

 as we have in our power to use for their destruc- 

 tion. It would be impossible within the space at 

 present at my command, to enter fully into the 

 details of the habits of all our agricultural insect 

 pests, therefore I shall only endeavour to trace 

 the habits of some of the most remarkable or 

 important, trusting that these may suffice to 

 illustrate the importance and interest which 

 attaches to the study of this particular branch of 

 insect life. 



Although of such diminutive size and fragile 

 structure, the Plant-lice, Green-fly, Blight, or 



