42 
the State, in Scotts Bluff County, eastward to the junction of the North 
and South Platte. It was not found on the South Platte, except very 
sparsely between Ogallala and North Platte. With the exception of 
isolated points, notably Gehring, Crawford, and Ainsworth, this species 
was not, however, guilty of most of the damage that was at that time 
reported from that region. This area is within the subpermanent 
region, and the locusts that have done damage this season are of the 
swarm that entered in the fall of 1895. The natural tendency to 
become weakened and die out in this region has been counteracted by 
a Series of seasons unusually favorable for their continuation. The 
result is that instead of dying out they have unexpectedly been on the 
increase, until this year they have attracted great attention. 
It must not be understood that there has been a spretus plague in 
Nebraska this year, because such is far from having been the case. 
The same conditions that have caused the present aspect of affairs 
regarding spretus have brought about an immense increase of the native 
species. Inthe total amount of damage that has been done, the amount 
attributable to spretus, in comparison to that by native species, becomes 
quite insignificant. The truth is, however, that Nebraska has suffered 
more this season than in any season in the last ten years. 
During the month of September spretus left the region where it 
hatched, in swarms. I was much interested to note a weak return 
swarm passing over the Black Hills, in South Dakota, on September 12, 
and have been at considerable pains to investigate this point further. 
I have been unable, however, to obtain any trace of other such swarms. 
Since there have been numerous swarms in the normal direction, and 
no one has informed me of any, nor have I observed any other than this, 
one weak one. I consider that it does not change materially the aspect 
of the case. 
Reference to the files of the Weather Bureau Station here sheds the 
following light on this exceptional, spasmodic return flight, as well as 
on the general southeasterly flight during the month of August. With 
the exception only of the 3d and 4th the wind in the region of the 
Black Hills was southeast and south, and only on two days as nearly 
toward the northwest as due northeast. The general direction for this 
month was decidedly toward the southeast. This condition prevailed 
the first six days of September. On the 7th, however, the wind 
changed to the north, and on the 8th it blew toward the northwest, 
and on the 9th south, but weak; on the 10th northwest; on the 11th, 
the day preceding this occurence, toward the northwest in this region 
and in all the surrounding country. There is no doubt that this wind 
will explain this flight and that the decidedly southeasterly direction 
of the wind—it blowing northwest only three isolated days subsequent 
in this month—explains the absence of other northerly flights and the 
noted southerly ones. 
During the greater part of September loose swarms of the Rocky 
Mountain locust might have been seen in almost any part of the State 
