﻿OF THE STATE ENTOMOLOGIST. 161 



leave a scattering rear-guard behind, and are generally followed by 

 new swarms ; and a country once visited presents for weeks the spec- 

 tacle of the insects gradually rising in the air between the hours of 

 9 or 10 A. M. and 3 p. m., and being carried away by the wind, while 

 others are constantly dropping. 



ITS NATIVE HOME : IT CAXXOT THRIVE IN THE MlSSISSIPn VALLEY, AND CAN 

 NEVER REACH FAIl INTO MISSOURI. 



A full month before a single specimen of the Rocky Mountain 

 Locust reached Missouri in 1874, 1 prophesied that it would come into 

 our western counties too late to do any very serious damage, and that 

 it would not reach beyond a given line.* To the many anxious corre- 

 spondents who, fearing that the State was to be overrun, as Kan- 

 sas was being overrun, wrote for my opinion and advice, I replied: 

 " Judging of the future by the past, the farmers of Missouri, east 

 of the extreme western tier of counties need fear nothing from Locust 

 invasions. They may plant their Fall grain without hesitation, and 

 console themselves with the rellection that they are secure from the 

 unwelcome visitants which occasionally make their way into the 

 counties mentioned, and especially of the northwest corner of the 

 State. The same holds true of the farmers of Illinois and of all the 

 country east of a line drawn, at a rough estimate, along longitude 17° 

 West from Washington." 



The detailed account already given (p. 144) of the counties in Mis- 

 souri invaded in 1874, will show how subsequent events bore out my 

 prophesy, and how the insect reached just about the limit I had given 

 it. But, it will be asked, " Upon what do you base this conclusion, 

 and what security have we, that at some future time the country east 

 of the line you have indicated may not be ravaged by these plagues 

 from the mountains ? " I answer that during the whole history of the 

 species as I have attempted to trace it in the chronological account 

 already given, the insect never has done any damage east of the line 

 indicated, and there is no reason to suppose that it ever will do so for 

 the future. There must of course be some limit to its flight, as no one 

 would be foolish enough to argue that it could, in one season, fly to 

 England or France, or even to the Atlantic ocean ; and as its flight is by 

 law limited to one season — for the term of life allotted to it is bounded 

 by the Spring and Autumn frosts — so its power of flight is limited. 

 And as the historical record proves that it never has done any dam- 



» St. Louii Globe, July 20, 1874. 

 E R — 11 



