1877.] The Destructive Locust of the West. 25 
of the prevailing winds, for they have no leaders, and we do not 
believe in the existence of a “ migratory instinct ” in the locust 
any more than in the grass army worm, or the cotton army 
worm, which it is sufficiently evident migrate from field to field, 
simply in search of more abundant food. Meanwhile the repro- 
ductive system of the locusts is maturing, the eggs ripening, and 
the uneasiness of the locusts during the course of their travels 
may be unconsciously stimulated by the sexual instincts and the 
desire to discover suitable places for egg-laying, a long and tedi- 
ous operation. 
It has been sufficiently shown that a swarm of locusts atinstven 
by Professor Robinson near the entrance to Boulder Cañon, Col- 
orado, traveled a distance of about six hundred miles to Eastern 
Kansas and Missouri. Though the swarm was first observed at 
some distance north of Denver, Colorado, it was then on its way 
from the north, and may have come from some part of Wyom- 
ing two or three hundred miles northwestward or northward. 
Though the winds may vary, and counter-currents exist, and 
storm-gusts from due north, such as often sweep over the plains, 
and local southerly breezes may retard their flight, the course is 
either eastward or southeasterly. We know enough of the winds 
in the Western States and Territories to lay down the law that 
the general direction of the winds in July and August, along the 
eastern slope of the Rocky Mountains and on the plains, is from 
the west and northwest, and accords with the eastward course of 
the locust swarms. The relations between the average direc- 
tion of the winds and the migrations of the locust have, however, 
never been sufficiently studied, either, so far as we are aware, in 
Europe or in this country. And yet if we would intelligently 
study the causes of the excessive increase and migrations of the 
locust, we must examine the meteorological features of the coun- 
try, ascertain the periods of drought and undue rain-fall, the av- 
erage direction of the wind for the different months, in order to 
learn how far they correspond with the phenomena of insect life. 
That there are meteorological cycles, dry and hot seasons recur- 
ring at irregular intervals, while the general average may remain — 
nearly the same century after century, is supported, though it 
may be vaguely, by observed meteorological facts. 
The question then arises; Can meteorologists predict the com- 
ing of seasons of undue heat and drought ? and consequently can 
we predict insect years? that is, the migrations of locusts and the 
undue increase of the chinch bug, and ste! and cotton worm ? 
