306 B. N. A. BOUNDARY COMMISSION. 

their rate of progress is from one-fourth to one-half mile per diem: In the — 
last week of July, 1873, I met the grasshoppers hatched out in the north- 
ern part of the Red River country, travelling southward down the valley. 
They were in the pupa stage, and appeared to be advancing more rapidly 
than the above measurement would indicate. Their fixed determination 
to travel southward was remarkable. 
721. On obtaining their wings, the grasshoppers prepare for flight, 
and only wait the advent of a favouring breeze, to set out in the direction 
which their instinct leads them to pursue. On July 12th of last year, I 
observed swarms ready for flight on the high plains of the third plateau, 
west of White Mud River, (long. 107° 35.) The day was hot and calm, 
and though many of the insects were on the wing at all altitudes in the 
atmosphere, they were following no determinate direction, but sailing in 
circles, and crossing each other in flight. The greater number were 
hovering over the swamps and spots of luxuriant grass, or resting on the 
prairie. A slight breath of air would induce them all to take to wing, 
causing a noise like that of the distant sound of surf, or a gentle breeze 
among pine trees. They appeared ill at ease, and anxiously waiting a 
favorable wind. 
722. The grasshopper has not intrinsic power of swift flight. It can 
bear itself up on the wing for a long time, but depends chiefly on the wind 
for propulsion, and travels fast or slow according to its motion. It flies 
only in the sunlight and during the warmer hours of the day, coming to 
the ground about 4 p.m., if the day be fine; or at any time when a heavy 
cloud covers the sun, or on the approach of a storm. Nor does it fly in 
any direction the wind may happen to blow, but has the extraordinary 
instinct to travel only on those days when the wind may favour it in its 
appointed course. This, as already mentioned, is generally south-east- 
ward, from its high-land breeding grounds to the lower and more fertile 
eastern regions. Itis not by any means invariably so, however; and 
some of the broods hatched this spring are already showing a similar per- 
sistent desire to move northward, while yet in their full strength and 
vigour. When the locust reaches nearly its eastern or southern limit, 
the organization of the swarms appears in great measure to fail, they move 
in almost any directon with the wind, or remain long on the ground — 
where food is abundant. After the deposit of eggs, which in the normal 
equence of events next happens, the insects are much exhausted, and 
soon die, though often making a last short fickle flight. 
723, Such is the usual life-history of the insect. The causes which 
