﻿162 SEVENTH ANNUAL REPORT 



age east of the line indicated, it is but logical to infer that it never 

 will. " Because an insect can fly 550 miles, it would be ridiculous to 

 argue that, therefore, it can fly 700 miles. We might as well claim 

 that because a man can jump a ditch twenty feet wide, therefore he 

 can jump another ditch which is thirty feet wide; or becaufje a man 

 can easily carry a young calf upon his back, therefore, if he practices 

 daily, he will be able to carry the same animal upon his back when it 

 has grown to be a cow."* 



My late friend, B. D. Walsh, who, from a number of data which 

 he accumulated, first laid stress on this fact that the insect would in 

 all likelihood never reach the Mississippi river, gives his reasons in 

 the following concluding paragraph of his report as acting State En- 

 tomologist of Illinois : 



Every man — except, perhaps, some crazy Millerite — believes firmly that, in all 

 human probability, the sun will rise in Illinois every raornino; for hundreds of years to 

 oome. Yet he has no other kind of evidence to justify such a belief, than I have to 

 iustify 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 Illi- 

 nois. Both the inorganic and organic worlds are governed by certain fixed laws ; and 

 whether it be a vast fiery globe of liquid larva, revolving slowly upon its axis in the 

 tnidst 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 Rocky Mountains over 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, what is and what 

 is not morally certain to happen in the future. 



"But why," it will again be asked, ''will not the young from the 

 eggs laid along the eastern limit you have indicated, hatch and spread 

 further to the eastward ? " Here, again, historical record serves us, 

 and there are, in addition, certain physical facts which help to answer 

 the question. 



There is some difference of opinion as to the precise natural habi- 

 tat and breeding place of these insects, but the facts all indicate 

 that it is by nature a denizen of high altitudes, breeding in the val- 

 leys, parks and plateaus of the Rocky Mountain region of Colorado, 

 and especially of Montana, Wyoming and British America. Prof. 

 Cyrus Thomas, who has had an excellent opportunity of studying it — 

 through his connection with llayden's geological survey of the Terri- 

 tories — reports it as occurring from Texas to British America and from 

 the Mississippi (more correctly speaking the line I have indicated) 

 westward to the Sierra Nevada range. But in all this vast extent of 

 country, and especially in the more southern latitudes, there is every 

 reason to believe that it breeds only on the higher mountain eleva- 

 tions, where the atmosphere is very dry and attenuated, and the soil 



fAm. Ent. I, p. 75. 



