The water boatman breathes by spiracles, and carries his supply of air
with him. All grown-up bugs breathe by spiracles.
Now look down into the pond. I think you will see some water boatmen
anchored near the bottom.
Yes, May, they cling by their front feet. Their hind pair of legs are
rather odd-looking; they have a fringe of hairs on the inside.
John says their hind legs are modified to swim with.
Very good, John.
The hind legs are the oars that row these little boats about in the
water.
But why are the little boats that have come to anchor down there moving
their paddles so constantly?
Ah, yes; it is because they want fresh air to breathe.
You know there is always air in pond water, and they keep their paddles
moving, so as to change the envelope of air that surrounds them.
[Illustration]
They know what to do to take care of themselves, if they _are_ nothing
but little bugs.
When winter comes, they go down to the bottom of the pond and bury
themselves in the mud. They lie there without moving or breathing until
spring, when out they come, as lively as ever.
Yes, certain other animals pass the winter in this way; the bears, for
instance, find a snug den and sleep all through the coldest winter
weather. We call this winter sleep of animals hibernation, and many of
the insects hibernate.
Yes, Ned, hibernating animals can get on with very little air; they
sometimes seem to need none at all, and they take no food.
May wants to know what these queer water boatmen eat.
They suck out the juices of other insects.
They must lay their eggs in the water, little Nell thinks.
And so they do, on water plants.
Near the city of Mexico there are species that lay enormous quantities
of eggs in the ponds, and what do you think? The Indians mix these eggs
with meal, make them into cakes, and eat them.
The Mexican bugs are gathered by the ton, too, and sent to England as
food for cage birds, fish, and poultry.
Little Nell thinks there must be a great many bugs in a ton. Indeed,
there are, probably about twenty-five millions of them; so you can
imagine Mexico is well supplied with water boatmen!
When the young ones hatch out they look like their parents, only, of
course, they are tiny little dots of things that have no wings.
But they eat and grow and moult like other larvæ until they are
full-grown insects.
What have you discovered, Ned? You look surprised.
The water boatman has no antennæ!
It doesn't seem to have any. But look carefully and I think you will
find some tiny ones tucked away under its head.
Nell wants to know if the water boatman has a thorax and an abdomen.
Indeed, it has, but you will have to look carefully to see them. Its
abdomen is short and thick and hard. The water boatman is much more
compact in form than the Orthoptera, or any of the other insects we have
studied.
You are right, John, an insect with a long abdomen, like the
grasshopper, could not get on very well in the water.
Now, May, take the cover off the tumbler. There!
Our water boatman was not slow to make use of his wings.
Well, good-by and good luck to you, little water boatman.
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