No. 6.] RILEY — ROCKY MOUNTAIN LOCUSTS. 373 



as the flight is for the most part over the vast and thinly-settled 

 plains of Indian Territory, Kansas, Nebraska, and Colorado, the 

 number that has dropped and been lost to sight in said plains is 

 infinitely greater than that which has been observed to come 

 down in the more thickly-settled regions to the east. 



The more dense and extensive swarms that flew before the 

 1st of July reached, I have little doubt, the great thinly-settled 

 plains and prairie region of Northwest Minnesota, Dakota, Mon- 

 tana, and British America, — embracing in the latter case most 

 of the country between the projected line of the Canada Pacific 

 and the boundary line, and between Manitoba and the Rocky 

 Mountains. I found the insects sparsely spread over the rank 

 prairies west of Brainerd along the Northern Pacific and along 

 Bed Biver; and by this I mean that a few would hop from the 

 grass at every step, wherever I searched for them. I met with 

 only here and there a straggler in Manitoba ; but early in July 

 they flew from the south over the country west of the province, 

 and reached the North Saskatchewan at several points, passing 

 many miles north of Fort Carleton. 



The insects that rose after the first week in July (mostly from 

 restricted parts of Minnesota and Dakota) bore for the most part 

 southwardly, while many of those which passed to the northwest 

 earlier in the season returned. Thus, swarms more or less scat- 

 tering have been passing for the past two mouths over parts of 

 Iowa, Nebraska, and Kansas, in varying directions, but mainly 

 to the south and southeast. They have lately reached into the 

 Indian Territory. In no instance have they done serious damage, 

 and the reports that come to me are singularly unanimous on this 

 point. The movements of the iusects that bred in Minnesota 

 this year were very similar to the movements of those that bred 

 there iu 1876. They at first flew to the northwest, but were 

 subsequently brought back, and" travelled over parts of Iowa, 

 Nebraska, and Kansas. The difference between the two years 

 is that the flights that thus turned back on the original course in 



1876 were recruited and followed by immense and fresh swarms 

 from the northwest plains regions, where, far beyoud the boundary 

 line, they hatched and bred innumerably; whereas the Minnesota 

 swarms of 1877 have not been recruited because there were few 

 eggs laid in 1876, and no insects of any consequence reared in 



1877 in said northwest country. It is upon this fact that I have 

 founded the belief in no serious devastation in the southeast 

 country this fall. 



