84 REPORT UNITED STATES ENTOMOLOGICAL COMMISSION 
full) we are wan-anted in saying they were from some point still farther 
south. These facts make it certain that the swarms of May were from 
Texas; and, as we know from the abundant data received from that 
State, chiefly from the central part. The distance traveled over in this 
movement was some 900 or 1,000 miles. From similar testimony it can 
be shown that the locusts hatched in Kansas and Nebraska, in 1875 r 
moved as far north in their return flights as the Saskatchewan in British 
Columbia, or about thirteen degrees of latitude. Invading swarms from 
the northwest can be occasionally 1 raced an equal distance in their 
movements southward and southeast. 
If we count the cut ire distance back and forth, north and south, which 
some of the locusts evidently traveled in 1877, it will certainly exceed a 
thousand miles. It is, therefore, possible for a swarm of the Rocky Mount- 
ain locusts to travel in the course of their migrations a distance of at 
least a thousand miles, with favorable winds, and it is also certain that 
they do frequently traverse this distance. The fact that our locust can 
and frequently dues travel a thousand miles being established, there is 
nothing to forbid the supposition that P. migratorius may extend its 
migrations in a single season from the Crimea or farther east to Poland 
and Germany, and that the resulting brood may reach England the fol- 
lowing season if the climatic conditions are favorable. Nor is there 
anything impossible in the statement of Major Moore, that A. pere- 
grinum passed from Arabia into India in a single migration. C. italicus 
does not appear to be capable of such extended movements. 
As a matter of course the extent of their movements depends very 
laigely on the winds, as we shall hereafter see when we touch upon this 
point. 
3. THE SPACE OVER WHICH A SINGLE PLIGHT MAY EXTEND. 
This is a question more difficult to decide, and one in reference to 
which there are stfll greater differences of opinion. 
That it is the usual rule for swarms to alight in the evening and arise 
again in the morning if the wind and weather favor is undoubtedly true, 
as will hereafter be shown ; but that they may, and sometimes do, fly in 
the night, can be clearly shown. As they rely chiefly upon the wind to 
bear them along, the distance to which a single flight may extend de- 
pends upon the rate at which the wind moves and the length of time the 
locusts can sustain themselves in the air. That they can sustain them- 
selves an entire day in the air is too well established to require any fur- 
ther proof here. The experience of 1877 led many persons in the West 
to the conclusion that they can remain in the air for days without com- 
ing down. While this is an extreme opinion, there are incontrovertible 
facts which go to prove that they do sometimes continue their flights 
for at least an entire day or more. 
The rate at which they travel is variously estimated at from three to 
