1875 AND 1876 CONTRASTED. 
77 
Some sections of Minnesota, Dakota, and Northern Iowa were visited 
in this year, but it is impossible to ascertain now whether these were 
''invaders" or not. It is known that in some cases they were from the 
south. 
1876. — It is only necessary to refer to our former report to see that 
this year was one of general invasion from the northwest reaching from 
Dakota to Texas. 
Now let us refer to the locust movements during these years in the 
permanent region. 
In 1875 the locusts visiting Fort Benton and Eastern Montana were 
from the east and southeast ; while those which appeared in 1876 came 
from the northwest in immense swarms. 
In Wyoming vast numbers were observed at Laramie City in 1875, 
flying south and southeast. In August of 1876 swarms were observed 
in Southeast Wyoming, east of the Big Horn Mountains and north of 
Black Hills, flying southeast. In Colorado the flights of 1875 were from 
the north and northwest, over Greeley and Denver. 
In 1875, as stated by Professor Dawson — 
Foreign swarms from the south crossed the 49th parallel with a wide front stretch- 
ing from the 98th to the 108th meridian, and are quite distinguishable from those pro- 
duced in the country (British Columbia), from the fact that many of them arrived 
before the latter were mature. These flights constituted the extreme northern part 
of the army returning northward and northwestward from the States ravaged in the 
autumn of 1874. 
From the same authority we learn that the locusts hatched north of 
the boundary line in 1876 flew southward into the United States. 
These facts are sufficient to show that the invading swarms which 
visit the temporary regions south of Dakota come, as a general and al- 
most universal rule, from the permanent area lying to the northwest r. 
and that the resulting brood of the following year return over the same 
course to the northwest. 
The movements in Wyoming and Colorado appear to be independent j 
coming out of the mountains, they move down the east flank into Colo- 
rado, sometimes stopping and producing a brood which next year either 
returns northwestward over the mountains, or as is sometimes the case 
moves farther southward, some passing southwest into South Park and 
adjoining regions, and at other times passing southeast into Texas- 
This will account for the appearance in Texas of invading swarms when 
in the sections north, as in 1875, there were no invading swarms. 
It appears that returning swarms moving north from Kansas and 
Nebraska through Dakota often turn westward near the middle of the 
Territory, following up the course of the Missouri. 
Those invading Manitoba come from the west generally, sometimes- 
from the northwest, but occasionally from the direction of Eastern Mon- 
tana. Those invading Minnesota, from the west and northwest. 
In the western States these invading swarms are very commonly desig- 
