466 



AiV EC 0X0 MIC ENTOMOLOGY. 



the hinder edge is stretched a canvas-covered, upright frame, at 

 least twelve inches high, which prevents grasshoppers from jump- 

 ing over the machine. The ' ' dozer' ' may be drawn by man or 

 by horse-power, and when in use the bottom is covered with crude 

 petroleum, or with water on which is floated a film of kerosene. 

 The canvas-covered frame is also moistened with kerosene. As 

 the apparatus is drawn through the fields the insects jump up 

 before, and usually, in trying to leap over, fall into it. Even if 

 they jump out again immediately, they are doomed, because 



Fig. 482. 



Hopper-dozer"' for man-power. 



once wet with kerosene they die in a few minutes. These 

 machines are useful only on comparatively level ground, but they 

 often destroy great numbers of injurious insects when properly 

 handled. 



Finally, we may say a few words concerning fumigating appa- 

 ratus. No two outfits are quite alike, and the work to be done 

 must in ever}^ case determine the character of the machinery. 

 The essentials are a gas-tight tent, and a means of placing it over 

 the plants to be fumigated. The method of producing the gas 

 is elsewhere described. For the tent, eight-ounce duck, saturated 

 with boiled linseed oil, is recommended, and it should be made 

 to close so tightly that little gas can escape through the lap. As 

 for the machinery to place it over the tree, that must be in all 

 cases determined by the circumstances ; but Fig. 483 will give an 

 idea of- the way things are done in California. The outfit is an 

 expensive one, and will pay only when an entire neighborhood 

 can be suppHed by it. 



