CHAPTER XIV 

 INSECTS, HARMFUL AND OTHERWISE 



FROM a human point of view insects have a great economic 

 importance. They are either useful or injurious. Many are 

 direct pests and nuisances. They frighten or disgust us; 

 they annoy us, like the flies; or they bite or sting us, like the 

 gad-flies, fleas, mosquitoes, and "yellow jackets." 



But the most harmful insects are injurious to man only 

 indirectly. They eat his crops, spoil his fruit, and injure his 

 trees and flowers, his books, furniture, and clothing. They 

 go into the pantry and make havoc there. The bot-fly 

 and the tsetse-fly kill his 'cattle. The losses inflicted by 

 insects in these various ways often amount to millions of 

 dollars yearly. 



Mosquitoes belong to the two-winged group. These little 

 insects can entirely spoil our enjoyment of outdoor life at 

 water resorts, in the woods, or even on the city veranda. 



The natural breeding places for mosquitoes are swamps 

 and marshes, though rain barrels, puddles, tin cans, etc. will 

 do. The female lays on the water, a boat -shaped mass of 

 eggs, which floats around till the eggs are hatched. The 

 larvae of mosquitoes are commonly known as " wrigglers," 

 and are frequently seen in rain barrels. Wrigglers breathe 

 air by means of a tubular organ near the posterior end of their 

 bodies. When at rest they are at the surface of the water, 



