RETURNING SWARMS DO LITTLE INJURY. 
81 
stance to distinguish an invading from a local swarm, although moving 
in the same direction and apparently from the same point. Those who 
have had considerable experience with them are generally able, from an 
inspection of the insects alone, to decide with reasonable certainty this 
point. But there are other and still more important methods of deter- 
mining it. 
It may appear of but little importance to the farmers and agricultur- 
ists of Kansas or Nebraska, on whose fields a swarm of locusts has fallen, 
whether they are from the plains of Montana or from the prairies of an 
adjoining State ; but if a careful study of their habits shows it to be a 
general rule that the invading swarms are always, or nearly always, 
destructive in their operations, and that the local swarms are seldom 
injurious, then this knowledge is important. 
One object of the Commission has been to study carefully this point, 
for the purpose of ascertaining whether there is any difference in this 
respect between the invading swarms and those which are local or re- 
turning swarms ; not only on account of its direct importance to the 
agriculturists of the invaded States, but also on account of its bearing 
upon the question of their continued vitality in these States. 
Early in the season, when rumors of flying locusts came from the 
South, the commissioners in the field were asked to express an opinion 
as to the result ; each, when asked, expressed his opinion without hesi- 
tation, and allowed it to be published far and wide : 
We do not apprehend any danger from them. In fact, this is precisely what the 
Commission anticipated, and is one of the strongest possible corroborations of the 
theory held, that these insects can never become permanent residents of this part of the 
Mississippi Valley. 
The result confirmed to the fullest extent this opinion, and our pre- 
dictions were fulfilled in a most remarkable manner. Although from 
the middle of June to the last of August of that year swarms were con- 
i stantly moving over Minnesota, Dakota, Iowa, Nebraska, and Kansas, 
some days covering an area equal to any two of these States, yet in all 
that time, though visited by myriads after myriads, scarcely a dozen 
fields in all these States were reported as injured. It may therefore be 
< stated as a general rule that returning and local swarms do but little 
injury. It is possible that with a different season the result may be 
different, but, so far as the facts heretofore ascertained are concerned, 
they point to the same conclusion ; therefore, with the experience of the 
past season added, we are justified in giving this as one general rule in 
reference to their habits. 
From the facts we have obtained it is evident that there is a marked 
difference between local flights in the permanent and temporary regions. 
In the latter, as just stated, the swarms appear to have little disposition 
to injure vegetation or to deposit eggs, the presumable reasons for which 
are given in our former report. While in the permanent area, apparently 
6l 
