the nation at a
less cost than in any other way.

REFERENCES

Grazing Lands. Report National Conservation Commission.

Grazing on the Public Lands. (Jastro.) Report Governor's Conference.

The Grazing Lands and Public Forests of Arizona. (Heard.) Report
Governor's Conference.

Grazing Problems in the Southwest and How to Meet Them. Bulletin, Dept.
of Agriculture, 5c.

Reports of the Bureau of Animal Industry. Dept. of Agriculture.

Distribution of Fish and Fish Eggs. Dept. Commerce and Labor.[B]

[Footnote B: All Bureau and Commission reports are free.]

Reports of the Commission of Fisheries.

National Fisheries Congress.

CHAPTER X

INSECTS

If we look at a watch, we see that one wheel can not move until the one
next in order to it moves, and that, in turn, must be set in motion by
another wheel. In the same way nature adjusts itself in its various
parts. Before man enters a region, the balance is perfect. Plants crowd
each other out of the way, the weaker giving place to the stronger; then
insects come to destroy them. These insects are destroyed by birds,
small mammals or other insects. The birds are killed by animals and
other birds, which in turn are the food of larger animals. And so
through all nature runs this law of balance; nothing increases in too
great a proportion.

But when man comes, he thinks only of his own needs and wishes and
begins at once to upset the delicate balance. Year after year, he plants
large fields of a single crop, and, calling other plants weeds, because
they hinder the growth of his grain, he drives them out entirely. The
insects that feed on these plants, finding no food, soon disappear,
while the ones which feed on the farmers' crops, finding food so
plentiful, are able to increase in great numbers. They increase all the
more rapidly because man, not knowing or not caring to know who his real
helpers are, has killed and driven away the birds that would feed on
them.

In order to readjust matters, he must learn how to destroy the insects,
or he can not have crops. Both the plant enemies, the weeds, and the
insects are always trying to bring about nature's balance again by
driving out the over-abundant field crop, so he must constantly fight
them in order to secure his harvest.

In no country is more harm done by insects than in the United States.
The losses to live stock and to plants, both growing and stored,
resulting from insects are greater than all