I SUPPOSE you have heard your mother wish there were not so many flies. The fact is, flies make us much trouble. Their noise tires and vexes people. They lay eggs in and on the food, and so spoil it. They cover our clean walls and glass with small black spots.
Will you wonder that there are so many flies when I tell you that one fly can in one season be the mother of two million others!
Many insects die soon after laying eggs. Bees and wasps do not, nor do flies. Bees and wasps take care of their eggs and their young, but the fly mother does not.
Mrs. Fly has more than a hundred eggs to lay at once. It is quite plain she could not take care of so many babies. She must let them all look out for themselves.
Still Mrs. Fly shows much sense as to where she puts her eggs. She finds a place where they will be likely to live and get food and grow.
If the place is too wet the baby flies would drown when they leave the egg. If the place is too dry, they would wither up and die. Then, too, they must have soft food.
The fly does not lay her eggs on a stone or a piece of wood. She lays them in some kind of food.
The fly can live all summer if it has a fair chance. Cold kills flies. A frosty day will kill them. Some few flies, like a few of the wasps, hide, and live over winter in a torpid state, and in the spring they come out to rear new swarms.
Birds, spiders, wasps, cats, dogs, and some other animals eat flies. These creatures kill flies by millions. People kill flies with poison and flytraps. If so many were not killed, we should be overrun with them. In the South is a plant with a leaf like a jug. On the seam of this leaf hang drops of honey. Its juice can make the flies drunk.
Flies like this juice. But as soon as they get it they turn dizzy and act just like drunken men. They fall into the jug-like space of the leaf and soon die. One of these plants will kill many flies in one day.
A Tavern by the Way
Many of our best birds live on flies, and if our birds were all dead we should have much greater trouble with the flies.
In the autumn you will see flies sitting about as if they feel dull and ill. If you look carefully you will see that the back part of the body is white. It seems to be covered with meal or mould.
Soon the fly dies. This white dust is a disease of the fly. It does not curl up its legs when it dies from this cause. They are stiff and spread out. The fly looks like a live fly. If you touch it, it crumbles to dust.
All around such a dead fly you will see a ring of white mould. This is perhaps a real mould, or tiny plant, that seizes on the body of the fly. It uses up all the soft parts, and so kills it, leaving only the dry shell.
There is another strange thing about this. The body of a fly that dies in this way is rent or burst open. The fly looks as if this dust or mould had grown large in the body and so torn it open.