172 The Rocky Mountain Locust. 



critical period in their history would have been brought 

 about much earlier if they had not had the cultivated 

 crops to feed upon ; and if, by concert of action, this sys- 

 tem of non-planting could at first have been adopted over 

 large areas, the insects would have been much sooner 

 starved out and obliged to congregate in the pastures, 

 prairies and timber. Moreover, the time required for early 

 planting and cultivation, if devoted to destroying the in- 

 sects after the bulk of them hatch out, toward the end 

 of April, would virtually annihilate them. The multipli- 

 cation of any species of animal beyond the power of the 

 country to support it, inevitably proves the destruction of 

 that species, unless it is able to migrate. Let fifty batches 

 of canker-worm eggs hatch out on a single, somewhat 

 isolated apple tree, and not one worm will survive long 

 enough to mature. The leaves of the tree will be de- 

 voured before the worms are half grown, and the latter 

 must then inevitably perish ; whereas, if only a dozen 

 batches of eggs had hatched on that tree, the worms 

 might all have lived and matured. In the same way, the 

 young locusts inevitably perish whenever they are so nu- 

 merous as to devour every green thing before they become 

 fledged ; and in certain circumstances, the sooner such a 

 condition of things is brought about, the better. The 

 greatest generals and the mightiest armies must yield to 

 starvation. 



Grain might also be sown in " lands " or strips, fifty to 

 one hundred feet wide, to permit of ditching between 

 them, and those who have fall wheat up and doing well, 

 where the eggs are thickly laid, should make ditches at 

 intervals through the field, to facilitate the saving of the 

 grain in the spring. 



In this connection it is also very obvious that our Sig- 

 nal Service might be made the means of giving important 



