DESTINATION OF DEPARTING SWARMS. 179 



We will now trace the June flights northward in order to ascertain 

 their probable destination, and to see what portion if any succeeded in 

 reaching the native breeding-grounds of the species. 



Without stopping to note the various sections from which swarms 

 arose between the 10th and 15th, we may state that our reports show 

 that on the 11th the front of the column moving north had reached the 

 latitude of Sioux City, Iowa, and extended from Blue Earth County, 

 Minnesota, on the east, to Western Kansas on the west. But as none 

 are reported in Nebraska west of Platte County, and an east wind had 

 driven those in Kansas westward on the 12th and 13th, it is probable 

 the advance was in two wings, separated by a broad interval. On the 

 16th the east wing, somewhat disturbed by a slight adverse wind in the 

 region of the Couteau des Prairies, presented an irregular line, the ex- 

 treme eastern flank being much the farthest advanced, reaching Otter Tail 

 County, Minnesota, on the 17th, while Southeastern Dakota is reached 

 on the 16th, the western column reaching the Platte Eiver on the same 

 day. As we have already traced the western column to the Black Hills 

 we may omit further mention of it. On the 18th a few reached the 

 Northern Pacific Eailroad at Worthington, Barnes County, Dakota, 

 going north, while a heavy flight crosses the Missouri at Standing 

 Kock, moving westward. But in Minnesota the course is changed, and 

 from Otter Tail, in the north, to Brown County in the south, they fly to 

 the southeast ; on the following day there was a slight movement to- 

 ward the west, but so far as the Minnesota section was concerned, from 

 this time forward until the close of the season they flew back and forth, 

 increasing in numbers until July 20, but never reaching farther north 

 than some point between the Northern Pacific and the international 

 boundary. 



In Dakota, the return south was a little later, but few passing north 

 of the railroad until we proceed westward to Bismarck. At this point, 

 light swarms passed to the northwest on the 20th and 21st; the flight 

 ceasing on the 22d, when a few came down, and was not renewed agaiu 

 until July 21. 



So far as Minnesota is concerned, and also all that part of Dakota east 

 of the couteau of the Missouri, it is quite certain that no swarms of any 

 consequence passed beyond to British America ; but that all or nearly 

 all that reached this region from the south in June, returned to the south, 

 died, or were driven off in some other direction. The crossing westward 

 at Standing Rock indicates the passage of a portion of the June flight 

 into Western Dakota, but there is nothing to show or to indicate that 

 this westward movement was general ; in fact, all the other reports from 

 Dakota show the movement to have been generally toward the north 

 aod northwests 



It is proper to state here that after the 22d up to July 7, while the 

 movements m Minnesota were chiefly to the south, except the northward 

 and westward flights of the 3d to the 6th of July, locusts eontinued to 



