CHAPTER XXVI 



INSECTS ON THE FARM 



And the locusts went up all over the land of Egypt, and rested in all the 

 borders of Egypt ; very grievous were they ; . . . For they covered the face of 

 the whole earth, so that the land was darkened ; and they did eat every herb 

 of the land, and all the fruit of the trees which the hail had left; and there 

 remained not any green thing, either tree or herb of the field, through all the 

 land of Egypt. THE BIBLE 



386. The importance of insects. The best authorities agree 

 that the injuries caused by insects equal at least 10 per cent 

 of the value of farm crops. This enormous loss is so constant 

 that few realize the total damage, which has now reached a 

 billion dollars annually. This is equal to the entire expenditures 

 of the national government, or it is more than four times the 

 annual national property loss by fire. 



Four fifths of all known species of animals are insects. About 

 350,000 different species have already been described, but it 

 is estimated that over 1,000,000 species exist. 



There are many insects, however, which contribute directly 

 to the wealth of the world. The silkworm produces over $200,- 

 000,000 worth of silk annually, and the honeybee produces 

 in the United States alone over $20,000,000 worth of honey 

 a year. Others contribute to the interests of man, as in the case 

 of those which pollinate the economic plants or those which 

 prey upon or live within the bodies of destructive insects, thus 

 preventing their depredations. 



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