VOL. I. | The Economy of Nature. 79 
like all beetles of this group, a considerable amount of canthara- 
dine. 
So the phenomenon of the grasshopper swarm demonstrates the 
same tendency of nature to destroy the prevalence of a single spe- 
cies or a small group of species (in our case the Artemisia or the 
Chenopodiacee of the alkali lands), but there is a difference in the 
means which nature applies in the destruction of the destroyer, or, 
let us say, in the second part of the phenomenon. It is not only 
that nature raises a destructive enemy in the parasite, and calls in 
the enemy in shape of birds which assemble around the swarms, and 
the coyote that follows them. Nature uses besides these remedies 
another and a most effective one. She implants in the locust swarm 
an irresistible instinct to wander. Millions are drowned in the riv- 
ers, others are crushed and mangled in the density and confusion of 
the wandering swarm, the bodies of others cover the ground at the 
foot of cliffs, walls of cities, and other insurmountable obstacles. 
Perhaps I should mention here an incident that to the non-ento- 
mologist is scarcely credible, but which is well calculated to give an 
idea of the destructive character of the migratory instinct as well as 
of the multitudes of the destroyers which perish. 
In the year 1844, when, on a voyage to Australia, the vessel 
passed the heights of the Cape Verde Islands, we sailed for more 
than two days through the bodies of grasshoppers, most of them 
dead or dying, but some still sufficiently strong to crawl out of the 
bucket which was used to draw the water for washing the deck. 
It is easy to understand that in presence of phenomena of such 
magnitude man is powerless. The grasshopper, or, as it is called 
in the English translation of scripture, the locust, is recorded 
as a periodical plague in all countries bordering on desert lands. 
Measures against this pest always have proved futile. Prayers have 
been ordered by all creeds at all times, by the authorities, and pro- 
fanity in all languages has been practiced by the suffering farmer, 
with equal success, till the calamity was removed by the remedies 
the plague carried along in its own nature. 
As far as I know there is no instance on record of a real intense 
grasshopper plague having visited the same district in two consec- 
utive years, a proof of the efficacy of the remedies applied by na- 
ture herself. 
These remedies are of four different kinds. First, the individual 
