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not by successive broods being raised one from the other on the 

 route, but by one single uninterrupted flight from the Rocky Moun- 

 tains, we have a right to ask, why it has never done so at some pre- 

 vious period? 



Our State has now been organized for about 50 years, and for 

 many preceding years it was sparsely inhabited both by the French 

 and by the English. Yet, in all that long period of time, no record 

 of any such Grasshopper-invasion of our State, as history shows to 

 have repeatedly taken place in various States to the west of us, and 

 in various years from A. D. 1820 up to the present year, 1867, can 

 be met with in any printed document, or gleaned from the trusty 

 memory of the "oldest inhabitant." Why is this? What possible 

 cause can be assigned, why, up to the year 1870, for example, the 

 Hateful Grasshopper should never have flown eastward from the 

 Rocky Mountains within 115 miles of Illinois, and in that particular 

 year should fly so many miles further east as to touch the sacred soil 

 of Illinois? The distance from the alpine regions of the Rocky 

 Mountains to the most easterly point that this insect has ever hitherto 

 reached, namely, the centre of Iowa, is about 550 miles. What is to 

 enable it at some future period to fly 150 miles further, or a total 

 distance of 700 miles, which it must do if it is ever going to swoop 

 down upon any considerable portion of Illinois from its present alpine 

 home? It surely cannot be the settlement of some portion of the 

 Intervening country, that will enable it to do so. This cause, if it had 

 any influence at all upon the length of its flight, would rather have 

 a tendency to diminish that length; for there is abundant evidence 

 that every invading army, composed of these Grasshoppers, drops a 

 portion of its numbers, as it goes along, wherever it finds abundance 

 of suitable crops to prey upon ; so that, the wider the extent of settled 

 country that it passed through, the sooner would such an army be re- 

 duced to nothing. Q^he only physical change that I can conceive of, 

 as likely to cause such an invading army to penetrate into Illinois, 

 is a sudden upheaval to the amount of many hundred feet of the 

 whole chain of the Rocky Mountains that lies to the westward of us, 

 so as to bring the native alpine home of this insect full 115 miles 

 nearer to Illinois. But modern geology teaches us that, although 

 such an upheaval may very probably take place by slow and gradual 

 steps in the course of the next 10,000 or 30,000 years, yet it can 

 never come to pass in our time, or in the times of our grandchildren, 

 or even in the times of our great-grandchildren twenty times removed. 

 Therefore we may infer, with moral certainty, that no swarm of 

 Hateful Grasshoppers can swoop down from the Rocky Mountains 



