47 



possess and cannot acquire — rapidity of multiplication, power of 

 concealment, a defensive armour, and many other factors. With all 

 this in view it will be necessarj* for the human species to bring the 

 great group of insects under control. We have ignored the insect 

 group to a certain extent on account of the small size of its members, 

 but their small size is one of the great elements of danger — is one 

 of the great factors of their success in existence and multipli- 

 cation."" 



""Nature," vol. 109, p. 79. 



