ACTING STATE ENTOMOLOGIST. 
103 
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 poition of the inteivening 
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 ciops 
to prey upon ; so that, the wider the extent of settled country that it passed through, 
the sooner would such an army be reduced to nothing. The 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 20,000 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-grand¬ 
children twenty times removed. Therefore we may infer, with moral certainty, that no 
swarm of Hateful Grasshopers can swoop down from the Rocky Mountains upon 
Illinois, within the only future that practically concerns us. But it was demonstrated 
before, that this insect could not pass into Illinois in the same mode as the Colorado 
potato-bug has done, namely, by breeding at various way-stations on the road. Theie- 
fore, as there are but two conceivable modes by which the Hateful Giasshoppei can 
reach Illinois, namely, 1st, at a single flight, or 2d, by breeding on the load, and as 
it has been shown that both modes are utterly improbable in the case of this species 
for hundreds of years to come, it necessarily follows that, in all human probability, it 
it will not pass into Illinois at all for hundreds of years to come. 
Every man — except, perhaps, some crazy Millerite — believes firmly that, in all 
human probability, the sun will rise in Illinois every morning for hundreds of years to 
come. Yet he has no better kind of evidence to justify such a belief, than I have to 
justify the truth of my theory, namely, that, in all human probability, we shall never 
for hundreds of years to come, be afflicted with the Hateful Grasshopper in Illinois. 
Both the inorganic and the organic worlds are governed by certain fixed laws; and 
whether it be a vast fiery globe of liquid lava, revolving slowly upon its axis in the 
midst of the attendant worlds, that have been circling around it, each in its own pecu¬ 
liarly prescribed path, for indefinite ages; or whether it be some infinitesimally 
minute insect, winging its way from the alpine heights of the Rock\ Mountains o\ei 
the Desert Plains of the West; we have but to ascertain by what laws each of them is 
governed, in order to be able to predict, in the case of each of them, v hat is, and what 
is not, morally certain to happen in the future. 
THE END. 
