The Insect Folk Part 4

The water goes in and out of this syringe, and the larva breathes as the fish does, by means of its gills.

Yes, May, its gills are in its syringe, which seems very odd,--you see the dragon fly larva breathes at its tail end instead of at its head end.

Mollie thinks it is an upside-down, inside-out sort of a creature anyway. But it knows what it is about.

Ned wants to know how it can get any air to breathe when it lives under water.

The truth is, there is always air mixed in with water, and it is this air the larva breathes when the water goes in and out of the syringe.

It uses the syringe for another purpose too. When it pleases it can shoot out the water with great force, and thus propel itself quite a distance.

By means of the syringe it can leap through the water faster than it can move by its slow-going legs.

Mollie wants to know if we can see the syringe.

No, it is inside the body.

But there is a kind of dragon fly that has a pair of gills outside, at the end of the abdomen, instead of the syringe inside.

The best I can do is to show you a picture of one. Some day we may find it in the pond.

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Those two feather-like parts at the tail end are gills.

Yes, John, it can propel itself through the water by rowing, as it were, with these gills.

There are some species of dragon fly larvae that swim by moving the tip of the abdomen from side to side, as a fish moves its body when it swims.

But now let us return to our funny larva that lives at the bottom of the pond. It stays down there, eating and growing and moulting, for nine or ten months or even longer; then something very wonderful happens.

It suddenly feels a great desire to get up to the top of the pond.

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It climbs up a weed or a stick until it is clear out of the water.

Then its skin splits down the back for the last time, and out there pulls itself, not a larva, but a weak-looking dragon fly, with soft and flabby little wings.

Now is its hour of danger, and now is the time for such birds as like the taste of young dragon flies to help themselves.

Catbirds seem to have a special fondness for these helpless insects, and have been known to eat them before the flabby little wings had grown stiff.

If the birds do not find the newly emerged dragon fly, it remains motionless an hour or so, but it does not remain unchanged.

Its wings stretch out and harden.

Bright metallic colors begin to play over them and over its body; and all at once--off it darts, away and away, glittering in the suns.h.i.+ne, a swift, beautiful winged creature.

Towards the end of summer you will often see dragon flies darting about in every direction.

They seem to come in swarms and I think they usually come where there are ponds or marshes, for in such places there are many gnats and mosquitoes.

Mollie wants to know why it would not be a good plan for people who live where there are many mosquitoes to raise dragon flies?

That is a very sensible idea, Mollie, and it has been tried.

Yes, indeed; some men once collected dragon fly larvae, and took care of them until they changed into dragon flies.

Then what do you think happened?

As soon as they got their wings, away went those dragon flies,--away and away, without stopping to catch a single mosquito for the men who had taken the trouble to raise them.

The dragon flies will not stay at home.

They fly so fast and so far there is no use raising them.

They are among the swiftest and strongest of insects.

How do the larvae get in the ponds? Frank is asking.

I will tell you what I know about it.

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The winged dragon flies mate, and the female then drops her eggs in the water or lays them on twigs in the water, where they hatch out into larvae.

The dragon flies have to be very careful when they go close to the water to lay their eggs.

You all know why.

Yes, it is because the frogs are on the watch to catch them.

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The mother dragon fly knows the larvae have to live in the water, and so she takes pains to put the eggs there; sometimes she even crawls down under the water on stems of plants to lay her eggs. Isn't she a wise little mother?

There are a good many species of dragon flies.

Some are large and some are small.

Some are bright and some are dull.

There are black ones and bright blue ones, or green ones with blue eyes.

Some are marked with red and yellow.

They are a very gay family.