Come, children; come with me.
Come to a pond I know of.
See how the water shines in the sun.
Over there is an old log lying on the edge of the pond.
It is covered with green moss, and a green frog is sitting on one end of
it.
Let us go and sit on the other end.
Goop! he says, and--plump! he has jumped into the water.
That is too bad, frog; we did not mean to disturb you.
How pretty it is here!
See the pickerel weed growing out in the water with its arrow-shaped
leaves, and its spikes of purple flowers.
See, down in the water are little fish, and very likely pollywogs are
there too, and lots of queer little things.
But who is this darting over the pond?
Ah, we know you.
You are our queer little, dear little old dragon fly.
Look, children; see the dragon flies darting about like flashes of light
in every direction.
They are having such a good time.
Whizz! One flashed right past Mollie's ear.
[Illustration]
Pretty people, I wish one of you would come and sit by us a little
while, so we could get a good look at you.
What is that, Ned? You have found a large one lying on the ground?
Sure enough; it is a beauty too, with a green body and silver wings.
Something seems to be wrong with it; it does not fly nor try to get
away.
What a big one it is!
My! my! what eyes!
Don't crowd, Amy; let little Nell see too.
What is that you say, Richard? "It catches mosquitoes and gnats and
flies and other insects while flying."
Yes, and that is why it has such big eyes. We should need big eyes
ourselves if we were to spend our time chasing mosquitoes.
Two eyes you have, little dragon fly, like the rest of us, but your eyes
are not like ours.
No, indeed!
Each of your big eyes is made up of a great many small eyes packed close
together.
Do you know, children, that some of the largest of the dragon flies have
as many as twenty thousand facets, or small eyes, in each large eye?
Think of it! Forty thousand eyes in one little dragon fly head. It
_ought_ to see well.
These facets are six-sided, excepting those along the edge, which are
rounded on the outside. You cannot see their real shape without a
microscope, they are so small. But here is a picture of some facets as
they look under the microscope.
[Illustration]
Eyes like these, made up of many facets, we call compound eyes.
All grown-up insects have compound eyes, though not many have as large
ones as the dragon fly.
Only insects that chase other insects or that need to see in the dark
have very large eyes.
See what a big mouth the dragon fly has. Its jaws do not show unless it
opens its lower lip, which fits over its mouth like a mask.