[64] REPORT UNITED STATES ENTOMOLOGICAL COMMISSION. 
In their native regions, when- the summer is hot and (lie herbage; abundant, their 
multiplication is excessive, and a fair and dry season is best adapted to their emigra- 
tions; sometimes they lly even to the borders of .Switzerland ; which puts me in mind 
of the fact that the troops of 1 he renowned Charles XII, when they traversed Bessara- 
bia, believed themselves overtaken one day by a hurricane, accompanied by a terrible 
hail-storm, when a vast swarm of locusts, which darkened the sun, began to fall, cov- 
ering men and horses and arresting the whole army on its march. 
Their voracity is most surprising. Gritndler placed some locusts under a globe of 
glass, in which some freshly-plucked stalks of barley had been placed. They first cut 
the stalks in two, then devoured from top to bottom all that remained at their feet, 
and then consumed every vestige of what fell on either side, with their greedy jaws, 
and all this with an avidity and agility that cannot be described. » » » 
And yet I think t hat the damage produced by each locust would scarcely merit the 
attention of the agriculturist, if they only came, like other species of insects, in small 
numbers. But when their swarms are composed of innumerable legions, similar to 
dense clouds, falling from the sky by their own weight, and accompanied by the most 
active powers of devastation and a surprising agility, they carry with them the dis- 
astrous advantage of their exorbitant numbers, which sometimes baffles all calcula- 
tions, falling upon a certain country and in the twinkling of an eve devouring all the 
plants in their pathway. Their first fury is discharged upon the delicate plants more 
abounding in juice ; but soon finding these giving out, and lacking their coveted food, 
they attack the leguminous plants, the leaves and the bark of trees, and, generally, 
all classes of vegetables, without sparing those whose odor or sap has something acid, 
sour, astringent, bitter, and even poisonous, and devouring equally coverlets of wool, 
and the clothing of the people of the country worn for protection irom the rain or the 
frost, and finishing with stuffs of flax ami of silk 
Upon the emigration of locusts, certain circumstances, as common as they are un- 
heeded, merit the attention of the observer. Their flight is more certain and at a 
greater altitude whenever the atmosphere is of a heated temperature and the air clear 
and calm. On the other hand, when the atmosphere is charged with mist or with rain, 
or pervaded by a chilly element, or even about the rising or the setting of the sun, 
they move more slowly, exhibiting a certain rigidity, moving their wings with diffi- 
culty, and not rising to any great height. And when they attempt to continue their 
raids in a rainy season, or one tending to cold, they begin by agitating their wings and 
exciting all their strength to rise; but, not finding themselves in a condition to sustain 
a long journey, they at first droop, and then fall precipitately to the ground, and are 
compelled to continue their journey on foot. 
The Irish writer William Bowles, in his "Introduction to the Natural History and 
Physical Geography of Spain,'' published and annotated by d'Azara, speaking of the 
locusts which devastated various provinces of that ki ngdona from 17^-1 to 1757, maintains 
the theory that the ardor of perpetuating their species is not equal in the male and 
female locust, observing that the male is restless and solicitous, while the female 
shows herself cold and always intent upon feeding. Whence it comes that the males, 
during the fresh hours of the morning, are for assaulting the females, w hile the latter 
are fleeing and hiding ; but in the first two hours of midday the females begin to free 
themselves from the importunity of tho males, who are continually pestering and 
pursuing them, and in this exercise mounting into the atmosphere to the height of 
400 or 500 feet, the first legion taking always the route which the wind favors, and 
going perhaps two leagues; and whenever the sky is serene and the air not agitated 
by winds their flight is very brief. From this cause, it is said, results the migration 
of the locusts. As declared by a Spanish countryman who saw his fields devoured by 
these pests: "If those accursed females would not act so prudishly, and if they would 
suffer the males to enjoy them in the country where they were born, I should not have 
to undergo this damage; but the vermin fear extinction, and seek to prolong life like 
ourselves, because they know that conjunction means nothing else than to impregnate 
and die." 
One would need to be very easily impressed by the marvelous in order to adopt the 
credulous belief of the Spanish countryman, and to persuade himself that the locusts 
forsee the consequence of copulation as fatal to them, and to attribute to the chastity 
and rigor of the females the migration of those innumerable colonies which come from 
the farthest east to the west of Europe. But wherefore should we not attribute this mi- 
gration rather to a cause both simple and natural, as well as founded upon an instinct 
of all organized beings — of gathering their own nourishment? Having consumed in 
one place all nutritious substances, why should they not, seek out another where food 
abounds? And this is, without question, the first of the three principal causes that 
determine the migrations of living species, commencing with man and continuing 
through quadrupeds, birds, some reptiles, zoophytes, gnats, and other insects; and to 
which have been due the immense reflux of barbarian tribes which have abandoned 
their northern boundaries to pour their inundations into the warm and fertile regions 
of the south. In fact, all thoso swarms of Goths, Huns, Vandals, Cirubri, Borgognoni, 
