4 INTRODUCTION- 



mated. By far the greater part of the annual toll goes unrecorded, — 

 often unnoticed. Each season every crop on every farm pays its tax, 

 whether large or small, to the bus}^, six-footed creatures that look to it 

 for food. It is only when we stop to consider what this total must be, 

 reckoned as a percentage of the value of all crops combined, that its 

 tremendous proportions become evident. 



The best observers agree that, in the average, insect depredations 

 equal at least 10 per cent of the value of all farm crops. Our agricul- 

 tural products in this country have now reached an annual worth of 

 $10,000,000,000. The total damage wrought by insects, therefore, may 

 fairly be placed at $1,000,000,000 each season! This is nearly five 

 times as great as the combined appropriations for the United States 

 army and navy; is equal to the entire bonded debt of the United 

 States ; is more than four times the annual property loss by fire ; more 

 than fourteen times the annual income of all colleges in this country ; 

 is sixty times greater than the funds allotted annually to the United 

 States Department of Agriculture. 



Value of a Knowledge of Insects 



Unquestionably, the loss due to insect attack may be reduced ma- 

 terially by the adoption of proper methods of prevention and control. 

 In many cases, the program to adopt involves no direct fighting, such as 

 spraying, but simply the shaping of farm, garden, or orchard practice 

 along lines unfavorable to the insects concerned — such matters as 

 judicious rotation of crops, or cleaning fields of weeds. To-day's 

 warfare against insect pests strives toward prevention as well as cure. 



In order to plan our campaign intelligently we need to know the 

 more important general facts about insects as a class : the main charac- 

 teristics of the different groups with which we have to deal ; how they 

 have fitted themselves to survive and multiply; what measures of 

 control are adapted to particular groups ; how the structure and habits 

 of one group render it susceptible to certain kinds of control measures, 

 such as spraying, while in other groups wholl}^ different measures are 

 necessary. To know these general facts is to possess a fundamental 

 advantage in conducting successful warfare. Not to know them usu- 



