sink, as the earth sinks over mines. Also, they have helped to bury
ruins and old cities, and to keep them safe hidden, until we found
them. We are glad when we learn of the old world days, from ruins which
the worms helped to hide.
Then, too, the worms help make the soil rich, by the dead leaves and
stems which they drag into their holes to decay. When the worms die,
their bodies also help to make the earth more fertile.
LESSON XIV.
MR. WORM’S COTTAGE BY THE SEA.
On the seashore you will find two or three kinds of worms. These are
called “Tube Worms,” from the shape of the houses which they build.
Some of them are called “Swimming Worms.”
The swimming worm is cousin to another family of creatures which look
like worms, but have many feet. They have a name which means “many
feet.”
You know that on most of the rings, in the body of the worm, are hairs
or hooks. You can see how easy it would be for these to become feet.
Each animal seems to have parts that are like some other animals,
and some new forms of its own. Thus, next the worm, with his rings
and hooks, comes another animal with rings and feet. Of all the ring
animals, Mr. Worm is the pattern, and after him comes his cousin, Mr.
Many-Feet.
While Mr. Many-Feet is like Mr. Worm, he is also like Mrs. Fly, and
seems to come between the two, a little related to both.
Now let us look at the seaside worms. Here we find some worms that have
eyes. We also find some that have little hard teeth, set in a ring
inside their mouths. There are some that have fine plumes, as gay as
any bird. These poor worms gleam like a rainbow.
[Illustration: Are they Cousins?]
New parts can grow on these worms as well as on the earth-worm, or
even better. Some say that they can even get a new head if the old one
is lost.
Some of these worms can bore into very hard things, as wood or stone.
Some of them shine like a fire. Ask some one to tell you of this kind
of light; it is like what we call Jack o’ Lantern.
Dig in the sea sand anywhere, and you will find worms, black, brown,
green, red, orange. They dig through sand and mud, and move very fast.
It is not yet known how these worms bore into stone and wood. Perhaps
it is by means of some acid stuff in their mouths. Perhaps it is by a
file, such as Mr. Drill has.[11]
If you look along the sea sand of some shores, you will find the
tube-homes of these sea worms. In their way of making a shell-home, and
making it larger as they grow, they are like the little shell-fish you
have read of.[12]
Most of these tube-homes are small, but some are very large. A
gentleman told me he had one with the bore or hole as large as his arm.
These worms by the sea serve as food for many fish and other creatures.
You know that nearly all fish like to eat worms, and that they are used
for bait. The boy who knew nothing else about worms knew they made good
bait.
He would have been full of wonder if I had told him that large worms
are used for food by men in some parts of the world. In this country we
do not make use of such food.
FOOTNOTES:
[11] First Book, Lesson XXXIX.
[12] First Book, Lesson XXXVI.
LESSON XV.
MR. WORM AT HOME.
Baby worms are just like the parent worms, only smaller, and with not
so many rings. As they grow, they get more rings by the dividing of the
last one.
In some kinds of soil the wee worms are born in a little hard skin bag.
This keeps them from harm, until they get strong enough to take care of
themselves.
Mr. Worm’s home is like a row of long halls. These halls are lined with
a kind of glue from the worm’s body. This glue makes the walls firm.
The halls are not deep under ground. If the weather is very cold, or
very dry, the worms dig down deeper. Worms dislike cold or drought.
They enjoy warmth. They also like water, and wet soil.
When winter comes the worms plug up the doors of their houses. This is
done by dragging into the doorway a plant stem that will fit and fill
it.
The worms carry into their homes leaves and stalks to eat. They bring
out, and throw away, things which they do not like. Worms show much
sense in the way in which they carry things in and out of their holes.
If a stem will not go in, they turn it over, and try it in some other
way.
[Illustration: Mr. Worm at Home.]
Worms usually come out of their holes at night or in wet weather. If
they go far from their house, they cannot find their way back. Then
they make a new hole. Each worm lives alone.
Often in the evening or early morning, or during rain, you will see
worms near their houses. You may find them with their heads just put
out of their doors. You will see the worm casts in early day or after
rain. It is then the worms dare to come out. Sun and heat dry worms up
very fast, and so kill them.
[Illustration: Mr. Worm leaving Home.]
The birds know all these ways of the worms. Watch a robin or a
bluebird. He searches for his food at sunrise, or after sunset, or
while it rains.
Now his keen eyes see the worm at his door! In goes his sharp bill! He
pulls like a good fellow! He is hungry. He wants his breakfast. The
worm holds fast by his hooks. The bird braces his feet and his tail,
and tugs hard. Out comes the worm to feed Mr. Bird.[13]
The bird shows great skill in the way he pulls the worm out of the
hole. He does not break off even one little bit of his soft body. No
boy could get him out in that way.
Some say that the worm lies by his door at sunrise for warmth. I do
not think that is so. I think what he likes is the fresh dew. He loves
dampness. He fears cold, but he also dies of heat.
Any worm will die in one day in dry air, but some kinds of worms will
live for weeks quite down under water. He needs an even, moist warmth.
His home must not be hot, nor cold, nor dry.
Little young worms know how to dig houses, make worm-casts, carry out
the soil, find food, and plug up the door of their houses. They know at
once all that old worms do. But then worm houses do not require as much
skill as bee or wasp houses.
The seaside worms make the prettiest houses. On shells, stone, wood, or
wound alone in a lump, you will find their tubes. They are white and as
hard as shell. Inside they are pink or blue.
These tubes curve and twist about, as the worm went that built them.
Some are very pretty. There is a soft kind of tube made of sand and
bits of shell, stone, and weed. The sand and weed are held together by
a kind of glue. The worm makes this glue in its mouth.
I have some tubes very clear and white. You can see the lines where the
worm went when he built them, ring by ring. Some of these tubes are so
small you can just run a fine needle into them. Some are as large as a
straw, and some as large as a fine fat earth-worm.
Now you see how much is to be learned, even of such a small humble
thing as a worm. Think how much even such a weak creature can do!
There is much more to be found out about worms, which I hope you will
be glad to learn for yourselves.
FOOTNOTES:
[13] See Third Book.
LESSON XVI.
A LOOK AT A HOUSE-FLY.
Look at a worm crawling about on the earth. Then look at a fly with
blue or green body and thin wings. See how it whirls in the air! You
will say, “These two are not at all alike.”
Yet there is one time in a fly’s life when it is very like a worm.
For this reason many wise people set flies and worms next to each other
when they study them.
You know, as soon as you look at a fly, that it is an insect.
You have learned that an insect has wings, six legs, a body in three
parts, and a pair of feelers like horns.
Insects breathe through all the body, and not by lungs as you do. They
have a row of holes in each side to breathe through.
The life of an insect passes through three states. These are the egg,
the grub or worm, and the pupa. When it is in the pupa it gets legs and
wings. The word “pupa” means _baby_ or _doll_.
There are some kinds of insects that vary in some of these points. The
fly is one that varies from this rule.
If you look at a fly, you will see that it has two wings, not four. It
is not one of the hook-wings.
Many insects can fold their wings. The fly cannot fold its wings; it
lays them back over its body.
Let us first look at a fly when it is most like an earth-worm. The fly
comes, in the first place, from a tiny egg laid by the mother fly.
When the egg opens, the baby fly is not like a fly, but like a little
earth-worm, both in its looks and in the way in which it is made. It
is a small white worm with rings, and on the rings are hooks.
If you wish to watch this change, lay a bit of meat in the sun on a hot
day. Soon flies will lay eggs on it.
The next day these eggs will be turned to grubs, which grow very fast.
The fly’s eggs are small and white, and are put upon the meat as if
they had been planted on one end.
The worm of the fly has a pair of jaws like hooks. It has two little
dots which will become eyes when it has grown to a fly. In the hooked
jaws and these eye-points it is not like an earth-worm.
The fly grub eats and grows. Then its skin gets tough and hard, and
forms a little case like a barrel. This shuts the worm in it, as in a
coffin. Now the baby fly seems to be dead.
But it is not dead. It is turning into a creature that has wings and
legs, and can fly and walk.
As the fly lies in its case, first the legs and then the wings grow. It
gets a head with mouth, eyes, and a trunk or tube, and from a poor worm
it turns to a wonder, as you will see.
But in its little coffin it is shut close, and its legs and wings are
all bent up. In a few days the change is made. Now it is ready to come
out.
It moves, and pulls, and gets free from the hard case. Then it strikes
the end of the case with its head time after time. At last it breaks
the case open, and out comes the fly!
Then it stands in the air, and in the sun if it can, and shakes itself.
It is cold and weak; but the air dries its wings and blows out the
wrinkles.
In a very few minutes the fly is strong and gay.
Then it spreads its wings and sails off to enjoy its life, and to look
for something good to eat.
LESSON XVII.
HOW TO LOOK AT A FLY.
Do you think a fly is a very small and common thing? Is it not worth
looking at? Let us see about that.
First, here is its head with two great eyes. We will soon look at the
eyes. Then you will see how curious they are.
There are, besides the big eyes, three little eyes. These are set on
the top of the head. Then, too, on the front of the head we find a
trunk or tube. And here is a pair of feelers. Inside the head is the
brain, very much like a worm’s brain. It is only a tiny white dot.
Next behind the head is the chest. The head has the shape of half of
an egg laid sidewise. The chest is nearly square. It is made of three
rings.
On the first ring is a pair of legs. On the next ring is a pair of legs
and a pair of wings. The fly has only one pair of wings.
On the last ring is a pair of legs. And near these legs are two little
clubs covered with fine hair. It is by means of these clubs that the
fly can halt or balance on the wing. They help the fly as the second
pair of wings helps other insects.
[Illustration: On the Wing.]
The third part of a fly’s body is the largest. It is egg-shaped, and
joins the chest by the thick end. This part also is made of rings.
Now let us look at the head of a fly. The feelers are like two long,
fine plumes made in joints. Most people think these feelers are made to
touch with. Their full, true use is not yet known.
You see, even in a fly there is much left for some of you to find out.
Some people think that flies smell and hear with these “feelers.” But
then they are so fine that a breath can jar them, and the fly might
_seem_ to hear when it only feels.
I know of something else like that. It is this. In some schools for the
deaf and dumb, the pupils are called to class or table by rapping on
the floor. The deaf do not hear the noise, but they feel the jar, and
come as if they could hear.
Let us look at the mouth of the fly. The lip of a fly runs out into a
long, slim tube or pipe. With this it sucks up its food.
At the end of this tube is a little flat plate. Close by it are two
sharp hairs. These are to prick the food, so that the tube can suck it
more easily.
When the fly is not eating, it can shut up this tube like a telescope,
to keep it safe. Did you ever see an elephant? Did you see his trunk?
The fly’s tube is his trunk. The elephant’s trunk is his long upper
lip. So is the fly’s trunk a long lip.
The chief parts to notice in a fly’s head are its eyes. These are so
large that they make up nearly all the head.
These big bright eyes look as if they had varnish on them. Now each of
these eyes is made up of a very great many small eyes. There are four
thousand of these small eyes.
[Illustration]
Between these two big eyes are three little single eyes, set in this
way--
Wise men have studied the eyes of flies for many years, and do not yet
know all about them.
The wings of a fly have a fine, thin, clear covering. This is held
out on a tiny frame, like a net-work. The fly moves these wings very
quickly. The motion of the wings helps to make the sound or _buzz_ of
the fly.
Now we come to the legs and feet of our fly. The leg is made in five
joints. The foot also has five joints. The last joint of the foot has
two claws and a little pad. These are covered with fine hairs.
The hairs catch on little points or rough edges. Thus the fly can walk,
as you would say, “upside down,” and does not fall. Besides, the pad
and hairs act like a sucker. They suck air from under the foot. So they
hold the fly from falling as he runs up a pane of glass. All boys know
what a “sucker” is and how to make one.
LESSON XVIII.
MRS. FLY AND HER FOES.
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.
[Illustration: A Tavern by the Way.]
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 fly-traps. 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.[14]
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.
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.
FOOTNOTES:
[14] See Reader, Seaside and Wayside No. III., Lesson XIII.
LESSON XIX.
OF WHAT USE ARE FLIES?
How often people cry out, “Oh, I wish there were no flies! What is the
use of a fly?”
But all things that God has made have their uses. And all God’s works
are worthy of study.
You have learned that worms are of great use. Let us see if Mrs. Fly
does any good in the world.
Mrs. Fly is of great use to man. She helps keep him in health. Do you
think that very strange?
People say, “Oh, these _dirty_ flies!” And yet these “dirty flies” help
to keep the world clean!
Now you know that over all the world, great numbers of animals die each
minute, and many of their bodies lie on the ground and decay.
Such bodies in decay cause disease and death to men. In winter, and in
cold places, such things do not decay so fast, and so do not make these
bad odors.
But in hot days, if such dead things lie about, they will poison the
air. Soon we should all be ill.
The work of Mrs. Fly is to lay many eggs in these dead bodies. In a few
hours these eggs turn to grubs, and these grubs to little live worms,
which begin to eat as fast as they can.
Soon they leave only dry bones, which can do no harm. They change the
dead stuff into their own fat, live bodies.
You know that the crabs are among the street-cleaners of the sea. So
the flies are among the street-cleaners of the air and land.
Did you ever watch flies dart about, here and there, with a flight like
hawks? They are eating up small, evil things, too small for us to see.
But these are yet big enough to hurt us if we should get them into our
lungs.
Ask your teacher to tell you a little about your lungs.
In and about our homes many bits of things drop, and might decay and
mould. This would make the air foul. But the busy and greedy fly drinks
up all the soft part of these things.
So we see that what we call the dirty flies help to clean away much
dirt. It is true too, that flies carry poison on their feet and trunks
from place to place. In this way they do great harm.
The fly serves for food for many birds, and fish and frogs, and some
insects. Some of these things we use for our food. Others are full of
beauty, or are of use to us, each in its own way.
Thus, though the fly is often a trouble to us, we find it is not
without its uses. Look at one of these little creatures through a glass
that will magnify it. You will see that the poor insect has really much
beauty.
From what you have read in this lesson you must not think that all
foul smells kill, nor that things that have no bad smell are always
safe. There are some gases that have no odor at all, which yet are very
deadly.
LESSON XX.
A SWARM OF FLIES.
Have you heard people speak of swarms of flies? By a swarm of flies we
mean a great number of flies rather near together. By a swarm of bees
we mean a number of bees that live and work in one place. A swarm of
bees divides the work of its hive. It has one queen bee. She is the
mother and ruler of the rest.
But flies have no home where they live in common. They have no work.
They have no one mother or queen, for whom the rest work. Each mother
fly drops her eggs where it seems best to her. Then she goes off. She
leaves her children to grow as best they can.
I have said that the fly likes best to place her eggs on a piece of
fresh meat.
These eggs soon turn to worms or grubs, and so spoil the meat. To keep
the meat from the flies the cook puts a cover over it. The cover is
often made of wire net.
“Now,” says the cook, “I can keep away that dirty fly.”
But Mrs. Fly says, “Oh, can you, Mrs. Cook? We will see about that.”
So Mrs. Fly sits on top of the wire cover. She puts her little egg tube
through one of the fine holes in the net. She drops egg after egg from
the tube. The eggs fall right on the meat, just where Mrs. Fly wishes
them to be.
Then the cook cries out, “How _ever_ did that fly get to my meat?”
Is it not strange that Mrs. Fly knows that her egg tube is the right
size to go through the mesh of the wire net? How does she know that the
eggs will fall on the meat?
Flies do another queer thing. If many flies are in a room, and you
begin to chase them to kill them, they hide. They creep into holes and
cracks.
They hide in curtains. They go behind pictures. After the hunt is
over, out they come, one by one!
Flies also know how to sham death, “play dead,” you would say. If you
hit one and make it fall, it will lie very still, and seem to be dead.
Then, after a little, it softly spreads out its legs and its wings.
Then it shakes itself. A moment more, off it goes.
This fashion of making believe to be dead does not belong to flies
only. Nearly all insects, and many other animals, sham death. It is
worth while to watch and see how well they do it.
When a fly is killed other flies come to eat up its body. They put
their trunks or mouth tubes on the dead fly and begin to suck. Soon the
body is sucked dry of all its juice. It is only a dry shell.
I will tell you something that you can do with a dead fly. If it has
not been dead so long that it has grown too stiff you can make the
wings move. Hold it by the body. Gently tip up one wing. As you lift up
one wing the other will rise too. They move together. It is as if they
were set on a little spring.
It is as wrong to be cruel to flies as to larger creatures. If they are
to be killed, do it quickly, and give as little pain as possible. If we
do cruel acts, we make our hearts hard and bad.
LESSON XXI.
SOME QUEER FLIES.
Although flies are of use, they also do evil to men in many ways. It is
well to look at things on all sides.
The fly you have been reading about is the common house-fly. That fly,
with its noise, dirt, and spoiling of food by laying eggs in it, is bad
enough. But yet the house-fly makes the least trouble of any of its
kind.
There are many kinds of flies. To the family of flies belong gnats,
midges, mosquitoes, and the big daddy-long-legs with wings.
You know well how some of these things sting, you say “bite,” you. Mr.
Daddy-long-legs hurts the grass lands with his grubs, which spoil grass
roots and the shoots of plants.
There is a fly called a “gall-fly” because it bites trees, and lays
eggs in twigs. Then upon the twigs grow over the eggs round balls
called “galls,” and these injure the trees.
There is also the “bot-fly,” which lays its eggs on the hide of the
horse. The egg causes the skin of the horse to itch. He licks the
place, and the egg goes into his stomach.
The egg of the bot-fly is apt to make the horse sick. The grub eats
holes in the stomach of the horse. That makes the horse sick. The
farmer will say that his horse is sick with “bots.”
In Africa flies kill horses and oxen by biting them. The bite poisons
the cattle and causes fever.
Farmers will tell you of a very bad fly that spoils wheat and other
grain. It is called the “Hessian” fly.
Flies, as they flit from place to place, sometimes carry with them
the poison of disease, as of sores and ulcers. Thus they spread these
troubles among people.
But while I tell you of that, I must not fail to say that flies, as
they go to flowers for honey, carry the dust of the flowers from one to
another. This helps new flowers to grow.
There is a large and handsome bright green fly, very fine to look at,
which bites horses and worries them. It is called the “horse-fly.” In
some lands a small sand-fly causes sore eyes.
Flies have been on the earth about as long as men have, or a little
longer, and there are some dead flies worth a great deal of money.
How is that? These are flies in amber. Amber is clear, hard, and bright
yellow. It is used for jewelry. Sometimes we see a perfect fly, held in
a clear, light mass of amber.
How did it come there? The amber was once a soft gum and the fly lit on
it. It stuck fast, and the amber flowed over it and grew hard, and so
buried the fly in a clear, golden tomb. A piece of amber with a fly in
it will bring a high price.
The “Spanish fly” is a large blue-green beetle. It is very handsome,
and is most useful when it is dead. It is used in medicine. It makes
blisters on the skin.
Do you say, “Oh, blisters are very bad!” Yes, they cause pain. But even
pain can be of use in this world. The blister, though it pains us, is
of use. It cures what might be a worse pain.
This Spanish fly is not a fly at all. It is a beetle which has been
given a fly’s name. It is put here at the end of the lessons on flies,
because in the next lessons you are to read about beetles.
LESSON XXII.
IN ARMOR CLAD.
Go to the garden or to the house plants, and after a little search you
will find one of the wonders of the world.