140 



ELEMENTARY STUDIES IN INSECT LIFE 



year on undisturbed soil are favorably placed for the 

 increase of these native grasshoppers. There is in the 

 undisturbed alfalfa meadow an opportunity for the 

 quiet hibernation of the egg and the proper nourish- 

 ment for the young insect. Life under such conditions 

 is free from many of the contingencies which arise 

 in the struggle for existence. Here these insects will 

 be found in undue numbers until they have by con- 

 tinuous defoliation destroyed their means of support, 

 the alfalfa ; or until the farmer has interfered and 

 removed them. 



FIG. 112. Plan for hopperdozer. 



It may not be possible to destroy all eggs by harrow- 

 ing and plowing. To insure the destruction of such 

 grasshoppers as may hatch, a machine called the " hop- 

 perdozer " is used. This consists of two shallow pans 

 about four feet long, two feet wide and eight inches 

 deep, placed on wooden runners corresponding in 

 height to the crop. At the back of these pans there 



