The dragon fly family is also a very old one.

Indeed, it is one of the oldest families on earth.

Long before there were bees or b.u.t.terflies or dogs or horses or human beings, there were dragon flies.

Don't you suppose that may be why the dragon fly is such a strange-looking insect?

It does not look like other insects; it is very old-fashioned, like the pine trees.

Pine trees, too, belong to a very old plant family that lived long ago, before there were oaks or maples, or other trees that shed their leaves.

Now we must go home.

Good-by, green frog, you may come back to your log now.

Good-by, pretty dragon fly people, we shall never forget you.

Good-by, pleasant pond and moss-grown log, we hope to see you often again.

[Ill.u.s.tration]

THE FAIRY MAY FLIES

[Ill.u.s.tration]

Come, children, and see! Hundreds and hundreds of them are dancing about.

What are they? Yes, May, they do make us think of the dragon flies, but they are like fairy demoiselles.

They are the May flies, fairy ships sailing in the sea of air.

See how they are tossed about.

Many have fallen to the ground, which is covered with them.

They live but a day, or sometimes only a few hours, and so they are called day flies, and also ephemerae, which means short-lived.

They have eyes, as you can see, little round eyes, but their mouth is so tiny they cannot eat.

Strange little beings to come into the world so helpless!

How different from the strong, fierce dragon flies!

See their dainty little legs. Six, you see, and legs and wings grow out from the thorax.

Have they an abdomen?

See the long threads at the end of it, they look like slender tails. How they spread these threads out as they fly!

They have four wings, but the wings are not shaped like those of the dragon fly, and they are very much more delicate.

[Ill.u.s.tration: DRAGON FLY WINGS.]

[Ill.u.s.tration: MAY FLY WINGS.]

Yes, May, I agree with you, they look like fine lace.

The fore wings, you see, are larger than the hind ones.

Richard asks, "Where do May flies come from? and why are they called May flies?"

Now, Richard, one question at a time, if you please, and the last shall come first because it is easier to answer.

They are called May flies because they often come out in the month of May, though sometimes not until June, and some species are as late as July in appearing.

[Ill.u.s.tration]

We shall have to look into the ponds and little streams to discover where they come from.

See, John has scooped up some little speckled grubs out of the mud. Is it possible that _they_ are the larvae of our fairy May flies? _They_ have a mouth!--see what big jaws for such little creatures.

And what do you suppose they eat?

No doubt they, too, live on animal food.

No doubt they move about in the mud and catch what they can.

You see, John had to dig them up; they like to burrow in the weeds and mud, and some of them even make tunnels of mud in which to protect their soft bodies. Their short, stout legs enable them to dig well.

Their bodies are soft, but their jaws are not. O dear, no!

[Ill.u.s.tration]

The grown-up May flies mate, and then the female drops her eggs on the surface of the water. When she does this a fish will very often jump up and seize her, for fish are very fond of May flies, and lucky are the May flies to escape these ravenous enemies.

The eggs are heavy and sink to the bottom, where they hatch into these queer-looking larvae that eat and grow and shed their skin just like the dragon fly larvae.

Those brushes along their sides are the gills they breathe with.

See the gills moving swiftly back and forth; they look as though the larva wished to swim with them, but this is not why it moves them so constantly.

The continual motion of the gills stirs up the water and keeps our larva supplied with fresh air.

Nellie is asking what gills are.