which from eggs laid in or just beneath the bark, hatch into
larvae which burrow into the wood, destroying its usefulness for lumber.
Among the borers which do most injury in destroying valuable timber are
the hickory-bark beetle, the bark-boring grubs which kill oak, chestnut,
birch and poplar trees, the locust borer, the chestnut timber-worm and
the Columbian timber beetle.

All these represent the loss from insects to the growing product; but
when it is stored, there is seemingly no less danger of attack by a
different class of insects. These include grain weevils and beetles,
flour-moths, the small fruit and vinegar flies, buffalo-moths and dozens
of others.

After these comes the loss to man and animals from insects. The cattle
tick alone, through the dreaded Texas fever, causes a loss of from
$10,000,000 to $35,000,000 in various years. The ox warble also preys on
cattle and causes a loss of probably $3,000,000 more. The buffalo-gnats,
gadflies, and other flies do on the whole a large amount of damage each
year.

Man has only discovered in recent years how serious a factor in his own
health as well as comfort, is the insect life about him. This subject is
more fully treated under the subject of health, so for the present we
need only say that flies, mosquitos and other insects are supposed to
cause some of our most serious diseases, and to be the indirect cause of
the loss of hundreds of millions of dollars and many human lives each
year.

Having thus summed up the damage done by insects, let us see what may be
done to prevent their spread and if possible drive out the most harmful
species entirely. Unfortunately, that seems almost impossible; so far
all man's efforts have only resulted in saving a larger or smaller
proportion of the various crops each year.

In insect control we turn first to the natural means of destruction.
Chief among these means are birds,--of which we will speak in another
chapter,--snakes and toads.

Toads live entirely on insects and catch large quantities of them. It is
estimated that a single toad is worth almost twenty dollars a year in a
field or garden. English gardeners are said to pay high prices for them
and to keep as many as possible in their gardens. Toads will eat almost
any kind of insect, are absolutely harmless, and should be carefully
protected.

There is one class of insects which, so far from being an enemy to man,
combines with him to kill the harmful insects.