ECONOMIC ENTOMOLOGY. 



INTRODUCTION. 



Economic Entomology is the science that treats of insects 

 which affect man and his interests. In a wide sense every insect 

 may be said to affect man, for those which appear to have no 

 direct relation to him, may still affect him by giving pleasure by 

 their external beauty, or instruction by their anatomy and physiology, 

 but so far as regards the collection in the Bethnal Green Branch 

 of the South Kensington Museum, of which this work is the 

 exponent, the term has been used in its more restricted significa- 

 tion as applicable only to insects that directly affect him in his 

 material interests — under which head the personal comfort of 

 himself and his dependents, the profit to be made from them, or 

 the damage done by them, are included. 



The number of insects that directly contribute to his benefit is 

 small; but that of those that directly injure him and the objects 

 in which he has an interest is very great — as is the number of 

 those that indirectly assist and benefit him by waging war upon 

 these enemies. 



There are unfortunately no means of distinguishing by a short 

 definition the former from the latter. In mammals, we can tell 

 by the teeth whether any species is carnivorous or herbivorous ; 

 and at first sight it would appear that we should be able to do the 

 same with insects by the parts of the mouth. If herbivorous, we 

 ,hould set them down as hurtful ; while those that are carnivorous 

 should be regarded as our friends, for they principally feed on 



A 2 



