140 The Rocky Mountain Locust. 



recognized by European and Asiatic governments liable to 

 suffer from the insects. The eggs, as we have seen, are 

 laid in masses, just beneath the surface of the ground, 

 seldom to a greater depth than an inch; and high, dry 

 ground is preferred for the purpose. Very often the ground 

 is so completely filled with these egg-masses, that not a 

 spoonful of the soil can be turned up without exposing 

 them, and a harrowing or shallow plowing will cause the 

 surface to look quite whitish as the masses break up aaid 

 bleach from exposure to the atmosphere. Great numbers 

 will be destroyed by such harrowing or plowing, as there- 

 by not only are they more liable to the attacks of natural 

 enemies, but they lose vitality through the bleaching 

 and desiccating influence of the dew and rain and sun. 

 Wherever hogs and cattle can be turned into fields where 

 the eggs abound, most of these will be destroyed by the 

 rooting and tramping. 



EXPERIMENTS WITH THE EGGS, AND CONCLUSIONS DRAWN 

 THEREFROM. 



There are many questions respecting the manner in which 

 the eggs of this locust are affected under different condi- 

 tions, which are of intense practical interest, and which are 

 frequently discussed with no definite result being arrived 

 at, and no positive conclusion drawn. Such are, for 

 instance, the influence of temperature, moisture and dry- 

 ness upon them; the effects of exposing them to the air, 

 of breaking open the pods, of harrowing or plowing them 

 under at different depths, of tramping upon them. Every- 

 thing, in short, that may tend to destroy them or prevent 

 the young locusts hatching, is of vital importance. With 

 a view of settling some of these questions, and in the hope 

 of reaching conclusions that might prove valuable, I carried 

 on, during the past winter, a series of experiments, some 



