64 The Rocky Mountain Locust. 



species might become profoundly modified in the direction 

 of Atlanis in the course of two or three generations in 

 the country to the southeast, and that in this way and 

 through miscegenation with our native species, its extinc- 

 tion from our territory might also be accounted for. The 

 same possibility has also been suggested by Prof. Thomas — 

 a professed anti-Darwinian — in an elaborate paper pub- 

 lished in October, 1875, in the Chicago Inter- Ocean, and, 

 as bearing on this point, I will state that the specimens 

 which hatched in and left the western counties of Missouri 

 in 1875, were, on an average, somewhat darker and smaller 

 than their parents. But after fully digesting all the facts, 

 I am convinced that these influences play a very unimpor- 

 tant part, if any; and that they can not be considered as 

 factors in the problem. All that could get away from the 

 regions of Texas, Missouri, Kansas, Iowa and Nebraska 

 ravaged in 1875, did so ; and if I may judge from expe- 

 rience in Missouri, those that could not, perished, so that 

 in the fall not a remnant of the army was left. 



But whatever the causes, the fact of debility, disease 

 and deterioration in, as well as migration from, the more 

 fertile southeastern country which the species occasionally 

 devastates, stands forth clearly and can not be gainsaid. 

 The following observations from careful observers may 

 be placed on record here : 



Mr. Rile}'- is of the opinion that the grasshoppers run out in a 

 few generations after they leave their native sandy and gravelly 

 soil. My experiments so far as they go, verify that opinion. For 

 several years I have caught grasshoppers during early summer that 

 came fresh from the direction of the mountains, and by attaching 

 their legs with fine silk threads to a small spring balance, found 

 that their physical strength was from twenty -five to fifty per cent, 

 greater than that of grasshoppers treated the same way that were 

 hatched in Nebraska or in States further eastward or northward. 

 The same result was reached by caging them, and ascertaining how 

 long they would live without food, and also by vivisection. In some 

 places, also, the eggs that were laid in different years since 1864 did 



