These insects contain a very brilliant, red coloring matter that is used by us in dyeing leather and wool, and in making paints. The insects are gathered and dried, and thus sent to market.
Although a few of them are useful to us, the scale bugs, on the whole, are a serious pest; and they are found on nearly all kinds of plants all over the world.
You should think all the plants would soon be gone, so many insects eat them?
Well, they would, only other things eat the insects.
Insects have a great many enemies, after all.
Sometimes the weather is bad for them, the season is too hot or too cold, too wet or too dry, and then they do not appear in large numbers.
Sometimes one kind of insect eats another kind.
Sometimes tiny plants, like moulds, grow on the insects and kill them; and birds destroy a very large number.
If the farmers only knew how much good the birds do them, they would never allow one to be killed. Even the crows that pull up their corn are worth many times the corn they eat in the insects they destroy. There is scarcely a bird but what is of value to the farmer.
The hawks that catch his chickens catch more mice and moles in his fields, than chickens in his barn-yard.