er.

These are the leaf hoppers.

What big heads they have!

And how daintily their green forms are pencilled with red lines.

There are a great many species of the leaf hoppers, and not all of them
are as pretty as these.

[Illustration]

Some of them are very small indeed, and some do great damage to the
grain crops and the fruits.

They suck out the juices of the plants.

If you sweep the insect net over bushes or through the grass in
midsummer, you will be pretty sure to draw in a good collection of leaf
hoppers.

Most of us are only too well acquainted with the rose-leaf hopper that
swarms on rose bushes and kills the leaves. If we have not noticed the
insect itself, we have not failed to notice the little white skins that
it has cast off and left clinging to the leaves.

Yes, these are the little skins it discards when it moults.

John says we can kill them by washing the bushes with strong soap suds.

[Illustration]

Ned says it is better yet to spray them.

It is better and also easier to spray them than to wash them.

You know there are machines for spraying trees and other plants. They
consist of a tank to hold the liquid that is to be sprayed and a pump to
force it through a rubber pipe with a sprinkler at the end.

Very often a mixture of soap and kerosene oil, known as "kerosene
emulsion," is used to spray with.

Paris green and blue vitriol, both very poisonous, are often used on
grape vines before the grapes are formed, and very gaudy vines they are
for a little while after this bright poison has been sprayed upon them.

Although insects are so very interesting, we have to protect ourselves
against many species in order to live.

Yes, John, it is oftentimes merely a question which shall profit by the
crops we plant, the insects or ourselves.

Sometimes the insects win, sometimes we win, but it is a closely
contested warfare all the time.

We plough the land and take care of it, we plant the seeds and keep out
the weeds. Then, when we have a fine crop growing, along come certain
destructive insects, feeling very happy, no doubt, to have found such a
feast.

Now the fight begins. They attack the crop, we attack them. We spray
them with poisons, burn up their eggs, do everything we know how to get
rid of them.

Wise men have spent many years of close study finding out the habits of
the insects destructive to grains and fruits, in order to be able to
destroy them.

Although ma