Pretty Leaf Hoppers
John says he once made a collection of tree hoppers and put them in a box with a reading glass over the top, and showed them to his friends to make them laugh.
May says she saw them, and they reminded her of Brownies.
Would it not be fun to have a tree hopper Brownie book!
The tree hoppers jump about on the bushes and eat the juices of the plants, but there are not usually enough of them to do damage. They seldom come in swarms like some of the leaf hoppers, though sometimes they do.
The jumping plant lice are nearly related to the tree hoppers, but they do not look at all like them.
Under the magnifying glass they look like tiny cicadas.
See, here is a picture of one enlarged.
Pretty Leaf Hoppers
Their natural size is no larger than a plant louse.
Have you not often seen them clustered close together on the young twigs of pear trees—tiny, light-colored things that jumped in all directions when you touched the twig?
The name of the plant louse that infests pear trees is the pear-tree psylla. It is very destructive to pear trees, sucking out the juices of the young shoots.
The pear trees can be saved by spraying them with kerosene emulsion as soon as the young leaves have opened in the spring.
Now, let us go in search of the aphids, or aphides, as they are also called. We shall not have to search far.
The Aphids
In a very dry season we generally need not search at all. All we need do is to examine the nearest weed to find plenty of aphides.
Yes, they are the little plant lice that seem at times to cover every growing thing.
Sometimes they are green, sometimes brown, or gray, or reddish, in color.
They are tiny creatures, but what they lack in size they more than make up in numbers.
Go now, and find some aphides.
Ah, here you all come, each bearing a leaf or a twig on which are aphids.
There was no trouble in finding them!
They do not hop like the jumping plant lice when they are disturbed. They remain where they are unless they are very much shaken up.
See, most of them are without wings, though here are a few with beautiful transparent wings.
Antennæ they have, long and threadlike. And see, the knowing little eyes!
They seem to be anchored to the leaf.
Hold the leaf up to the light, and see if you can discover what they are doing.
Ah, see those mouth tubes firmly stuck into the leaf. There they stand all day long and suck out the juice.
The Aphids
Ned says he should think they would burst.
But they do not; they grow. And they also get rid of a large part of the superfluous sap in a curious way.
They use what they need to grow on, and the rest escapes from the insect's body in the form of "honey dew." It is a sweet liquid of which ants and bees are very fond.
What, John, you have heard that the aphids give out honey dew from two little horns near the tip of the abdomen?
Let us see if we can find these horns. Yes, we can see them plainly, andveryplainly with a magnifying glass.
But now listen; the honey dew does not come from the horns. On the end of some of the horns, or tubes, we can see a drop of clear liquid.
For a long time people believed this was honey dew, but instead, it is a waxy substance which is not sweet.
It has been very carefully studied by wise men who tell us it contains no sugar and is probably used as a means of defence, as aphides have been seen to smear the faces of insect enemies with this wax.
There are a great many species of aphides, and not all of them have the little tubes or horns on their backs. But probably many that have no horns give forth honey dew.
It is really a waste substance from the body of the aphid.
Ants are so fond of the honey dew that certain species of aphides have been called theants' cows, because the ants take care of them for the sake of the honey dew.
Some ants protect the aphids from their enemies.They drive off those insects that would devour the aphids, and when winter comes these ants carry the aphids down into their warm nests under ground, and keep them safe through the cold weather.
The aphides cannot stand wet weather, but after a long spell of dry weather they will be found in great abundance.
The Aphids
Sometimes they eat so fast and so much that the honey dew falls like a shower from the trees upon which they are. It covers the ground beneath and the leaves of plants, and makes everything very sticky and disagreeable to the touch. The dust settles on it, too and a growth something like mould often turns it black—as we find to our discomfort.
But when the honey dew is fresh the bees love it. They collect large quantities of it and make it into honey. Squirrels like it to.
It is great fun to watch the nimble squirrel folk sitting in the trees and holding a leaf between their little hands while they lick off the honey dew.
Children sometimes suck the honey dew from the leaves in back country places, where sugar is scarce and where candy is seldom to be had.
Which side of the leaf does the aphid prefer?
Yes, it is on the under side always.
I wonder why.
John says the aphides would be better protected in case of a shower.
Ned says the skin is tenderer on the under side and easier to pierce.
Mollie thinks they want to be in the shade out of the hot sunshine.
I should not wonder if all of these reasons were right.
My little aphid, how many wings have you when you have any?
Yes, little Nell, they have four of the daintiest, prettiest little wings you ever saw.
The Aphids
True enough, most of them have no wings at all.
The Aphids
John thinks those must be young ones.
Sometimes they are, but not always. Many of the adult aphids have no wings.
The aphids are very curious insects, and when you are older I hope you will remember to study them carefully.
No, John, not all species of aphides make honey dew.
Some form instead a white, powdery substance that is seen scattered over the body.
May says that must be the kind she has.
Let us see. Yes, May's aphids produce the white powder instead of honey dew.
That istheirway of getting rid of the waste matter.
May says she is glad to know that; she thought her aphids had something the matter with them. They seemed to be falling to pieces.
No, May, they are not falling to pieces; that powder can all be rubbed off, and there are your aphids whole and sound beneath it.
Do you know that some species of your funny little tree hoppers secrete honey dew also, and even have ants to attend them? See if you can find some of these this summer.
Sometimes aphids live on the roots of plants as well as on the leaves.
Yes, indeed, May, they are very destructive insects. We have to spray our house plants to get rid of them, and often our garden flowers as well, and they do a great deal of damage to fruits and vegetables, and one of them, the phylloxera, has nearly destroyed the vineyards of France. It lives on the leaves of some species of grapes and on the roots of others. We have to be very carefulabout getting grape vines from Europe to plant in this country on account of the phylloxera.
The Aphids
What have you found now, John? Ah, yes, an alder branch, with a white, cottony substance on it. You have been poking into it with a little stick, and you think there are insects beneath it.
What, May, you always thought that white stuff was a plant growth, like mould?
We can easily find out. Get out some of the little things inside if you can, John. It is not easy to separate them from their cottony covering without crushing them, but now we can see quite well with the magnifying glass—and yes—you see they are little insects.
We call them the woolly aphids.
They also secrete honey dew.
You say the ground below the alder bush was all sticky and black, John?
That was the honey dew, blackened by a little plant something like mould, that grows on it.
We often see woolly plant lice in the summer-time on different plants, and one species injures apple trees. It gets on the roots as well as on the tender bark of young trees and kills them.
Yes, indeed, Mollie, the aphids are bugs. They belong to the bug order, which is a very large and important insect family, and contains some members that are exceedingly troublesome to us.
Scale Bugs
What, May, you are tired out?
What have you been doing?
Oh, yes, washing the scales off the leaves of your mother's window fern.
It must indeed have been a task; what did you wash them off with? Why did you use soap suds?
The Airy Water Striders
Because your mother told you to; well, that is a good reason, but why do you think she told you to use soap suds?
You say you don't know, but you think very likely these scales are some sort of bug, as everything nowadays seems to be bugs.
Well, I don't know about everything being bugs, but those scales certainly are. They are scale bugs.
Did you stop to look at them under the magnifying glass?
Scale Bugs
No, but you brought a piece of the fern for us to look at.
It will be necessary to put it under the microscope.
There, now look.
Yes, that scale looks like a tiny mussel shell; but look carefully, and you will see it has legs.
Lift it up with the point of a pin, and under it you will find a mass of eggs. Yes, Ned; it is like a quantity of eggs under a dish cover.
The cover is the female scale bug, and she has laid all those eggs.
Yes, the scales we see on so many plants are the scale bugs.
They are not all alike in shape, or size, or color; here is a different kind, you see.
But they are all very prolific; that is to say, they produce a great many young, and do it in a short time.
Yes, John, the tiny, dark-colored scales that look like little oyster shells on the skins of oranges are a form of scale bug, and a very troublesome one, too, to the orange grower.
But though most of these insects are troublesome, the family is redeemed by a few members that are of great value to us.
One of these is the scale bug that supplies shellac, and all that comes from it to our markets. These curious bugs give forth a resinous substance that envelops the eggs and glues them to the twigs whose juices the bug sucks out. It is this resinous substance that is collected by breaking off the twigs where the insects are. It is used for varnishes, as you know, and for polishing wood and other substances.
There are other scale bugs that secrete wax, and some of them produce it so abundantly, and of such good quality, that it has become an article of commerce. China wax, which is wax of a very fine quality, is secreted by a Chinese scale bug, and the wax is used for making fine candles, as well as for other purposes.
In Mexico we have the cochineal insect, which is a scale bug that lives on a cactus that grows in Mexico.
Like many others of the scale bugs, the cochineal males have wings and are not so scalelike as their helpless mates.
But they are of no use to us. It is only the female cochineal we use.
She is raised in great numbers in cactus gardens planted on purpose.
Here is the picture of a cactus with cochineal insects upon it.
Scale Bugs
These insects contain a very brilliant, red coloring matter that is used by us in dyeing leather and wool, and in making paints. The insects are gathered and dried, and thus sent to market.
Although a few of them are useful to us, the scale bugs, on the whole, are a serious pest; and they are found on nearly all kinds of plants all over the world.
You should think all the plants would soon be gone, so many insects eat them?
Well, they would, only other things eat the insects.
Insects have a great many enemies, after all.
Sometimes the weather is bad for them, the season is too hot or too cold, too wet or too dry, and then they do not appear in large numbers.
Sometimes one kind of insect eats another kind.
Sometimes tiny plants, like moulds, grow on the insects and kill them; and birds destroy a very large number.
If the farmers only knew how much good the birds do them, they would never allow one to be killed. Even the crows that pull up their corn are worth many times the corn they eat in the insects they destroy. There is scarcely a bird but what is of value to the farmer.
The hawks that catch his chickens catch more mice and moles in his fields, than chickens in his barn-yard.
And as for the robins, the blue jays, and all the small birds, they do more to save the growing plants, than all the soap suds and kerosene emulsion that were ever made.
No one should ever shoot a bird. The birds are our natural protectors against the vast armies of insects, that, but for the birds, would soon destroy us by eating up our food plants.
What is that, May? You belong to an Audubon Society for the protection of the birds?
Yes, I know you do, and so do John and Ned and Mollie and little Nell.
I wish every child in the United States belonged to the Audubon Society. Then our birds would be safe. They would never be killed as they are now for foolish women to wear on their hats.
When the Audubon Society children grew up they would not wear dead birds, of course, and their childrenwould be taught better, so that after a while the Audubon Society people would be the only ones left, and so the birds would be safe.
Let us get as many people to belong to the Audubon Society as we can.
What is that, Amy? You have learned more interesting things about birds in the Audubon Society than you ever knew in your life before?
Yes, I am sure you have, and what could be lovelier to study about than the birds.
What is that you are saying, Ned? You love to go bird hunting? Ah, I see your eyes twinkle, sir; I know how you go hunting. You hunt with your mother's opera glass! That is the proper way to hunt birds.
We can learn more from watching one bird with a glass than we could from shooting a hundred.
But you do shoot them, John? Yes, I know about that, too. I know what kind of a shooting instrument you got for Christmas, sir, and I have seen the birds you shot!
Yes, nearly all of us have seen them, and how well he does it!
What, Amy, you think John ought to be ashamed of himself to go about shooting birds, and we ought to be ashamed of ourselves to talk so about it?
There, now, don't be vexed with Amy, children. Shehas known us but a little while, and she has not seen John's birds, so I do not wonder she feels indignant.
What is that, May? You have one of John's birds right here in your school-bag? Show it to Amy.
Isn't it pretty! It is a very charming photograph of a catbird on its nest.
You see John shoots birds with a camera! His father gave him a beautiful one for Christmas, and he has made good use of it.
How long did it take you to get that bird, John?
Just hear! He spent more than a week getting acquainted with the bird so it would sit still on the nest while he took its picture.
I am sure that was a week well spent.
John says he feels better acquainted with the catbird than he would have been if he had read fifty books about it.
And I am sure he is right. The only way to enjoy a bird and to know it, is to watch it alive.
A camera is the very best gun in the world for catching birds. And it is really much better fun to take their pictures than to shoot and kill them.
It seems to me we have strayed a long way from bugs.
May says she thinks birds are much more interesting than bugs.
That may be, but still we want to know about bugs, too.
Do you think you will know a bug when you see it now?
No, I do not believe you can be sure of that. But at least you know something about a few bugs.
Some day you will study more carefully how insects are formed, and then you will understand better how we decide what order they belong to.
We group together the insects that are most like each other.
Scale Bugs
The Horned Corydalus
No more bugs, if you please.
We are to make the acquaintance of another order of insect folk this time.
I think we can find some worthy members of this new order if we go with John to a brook he knows of.
Here we are, and it certainly is a lovely brook, whether we find a dobson in it or not.
Yes, Nell, the dobson is the new insect we shall try to find.
Now, be careful and not get your clothes too wet, but we have to turn over the stones along the edge of the brook until we find what we are after.
Mollie wants to know how she is to know it if she finds it.
Well, Mollie, whatever you find that is interesting you must show us. Even though it is not what we are searching for, we shall enjoy seeing it.
Look at little Nell! She has tumbled into the brook. Her foot slipped, and down she went.
Don't cry, deary, you are not wet enough to do any harm. The warm sun will soon dry you.
No, indeed, you will not have to go home.
The Horned Corydalus
Perhaps you will be the first one to find a dobson after all.
Hurrah! hurrah! hear John shout!
He must have found the first dobson.
Yes, he has.
What, May? It is a horrid monster, and you have a good mind to scream?
Well, scream if you want to; that won't do any harm.
Itisn'tpretty! but we shall like to look at it. You see it is a larva and a big one, dark gray in color and with a thick leathery skin.
Mollie says it reminds her a little of the larva of the May fly; that is, in shape.
Let us look at a picture of the May-fly larva.
You see it has a head, a thorax to which is attached the six legs and the rudimentary wings, and an abdomen, all distinctly separated from each other.
The Horned Corydalus
The dobson has a head, but no thorax.
The body behind the head is divided into segments that all look very much alike, and there is a pair of legs attached to each of the first three segments.
The dobson eats other larvæ that it chews up with its strong jaws.
It lives almost three years in the larval state, so you see it has plenty of time in which to grow. Of course it moults. It is usually to be found under stones in swift, running water. Those two pairs of hooks at the tip of its body are its anchors.
It clasps them about a bit of stone or a stick that is firmly lodged, and then it can bid defiance to the swirling stream.
Ned wonders why it is always found hiding under stones.
Listen to John, he says fishes are very fond of dobsons, and that is why they hide away.
Fishermen hunt the dobsons for bait; so you see they have a hard time in spite of their large size and their strong jaws.
When they have lived nearly three years in the water they crawl out on the bank and hollow out a place under a stone.
Here they lie, apparently dead, but they are not dead.
They are undergoing a wonderful transformation.
It takes about a month for this transformation, ormetamorphosis, as it is called, to be completed.
All of our other insect friends have changed gradually from larval to adult form. At each moult they became a little more like their parents, and finally at the last moult, without any resting period, out sprang the perfect insect.
Not so the dobson. It goes into its hole in the bank a larva, almost exactly like the larva that hatched from the egg, only, of course, it is larger. There is no hint of wings. It has no separate thorax and abdomen. Could we see under the bank where it has crept, to undergo its great metamorphosis, we should find, not a larva, but a strange-looking, motionless object.
The Horned Corydalus
Here is the picture of one. See its little wing pads. And now it has a thorax and an abdomen.
It seems to have changed and been turned to some hard substance.
In this state it is called thepupa, which means doll. Is it not a cunning insect doll? But it is not really a doll. Although so still and apparently lifeless, yet it lives.
Some day it will burst its pupa shell and pull itself out—not a larva now, not a pupa, but a strong-winged insect.
In its adult form, it is known as the horned corydalus.
There! I thought John was saving one for us. Hehad it in a box in his pocket. Now see what a—a—what shall I say? A beauty? or a monster? That is just as you feel about it.
It certainly is an alarming-looking insect.
Male CorydalusMale Corydalus
This one is a male, as we can tell by the long, curved jaws that look very dangerous; but in this instance the creature's appearance is worse than its bite, and the real biter is the female whose jaws are smaller but very useful in nipping tormentors or biting prey.
Now here she is—a fit mate for her formidable-looking companion.
Female CorydalusFemale Corydalus
John, you were fortunate in your hunting.
In spite of its terrifying appearance, see what wonderful wings the corydalus has.
See! John has spread out the wings of the female.
They are indeed beautiful.
May cannot understand how those great wings came out of those little wing pads.
When the wings were first pulled out of the wing pads they were small, but they rapidly expanded and became thin and broad and long as the air touched them.
You will understand that better after a while.
The corydalus differs from all the other insects we have studied, in its metamorphosis.
It begins life far more unlike its parents than the other insects we have been looking at, for they had the thorax and abdomen distinct from the beginning. Instead of changing gradually and remaining active all the time up to the final metamorphosis, our corydalus goes into the pupa state, and in that motionless condition transforms to the perfect insect.
This is called a complete metamorphosis.
When the change is gradual, without any pupa form, any stopping place as it were, the change is said to be an incomplete metamorphosis.
Yes, the metamorphosis of the grasshoppers is incomplete, and of the katydids and the crickets and allthe other insects we have studied until we came to the dobson.
Another name for the larva of insects that undergo an incomplete metamorphosis isnymph. Some books speak of the nymph of the grasshopper, and never of the larva of the grasshopper. Such books use the wordlarvaonly in speaking of the young of insects that undergo a complete metamorphosis.
Yes, Ned, they would speak of the nymph of the dragon fly, and the nymph of the May fly and the nymph of the cricket and the katydid, but they would speak of the larva of the corydalus.
Egg, nymph, adult,—those are the stages of insects that have an incomplete metamorphosis.
Egg, larva, pupa, adult,—those are the stages of insects that have a complete metamorphosis.
No, it is not wrong to say larva instead of nymph. I only want you to know how the word nymph is used, so that when you see it in reading about insects you will know what it means.
The corydalus lays its eggs near the water, and it lays a great many—sometimes nearly three thousand. Think of that! The young larvæ crawl into the water as soon as they are hatched, and those that escape the hungry fishes grow into these large larvæ and finally metamorphose into the big-horned corydalus.
It is such a remarkably fierce-looking creature that it has received many names that are neither complimentary nor beautiful, such as conniption bug, alligator, and dragon, and numerous others equally expressive.
Now, we must go home. Let us put the dobson back into the brook.
It does no harm, and we will not kill it.
Yes, Ned, there are smaller insects like the corydalus that are near relatives to it, and I am sure you have often seen them.
Fairy Lacewing
Here is our little Lacewing.
May says it is a darling, like a woodland fairy clad all in green.
And, oh, its eyes! Are they not beautiful? They shine like gold.
Do its wings not remind you a little of the wings of the corydalus?
May says no, indeed; that has ugly brown wings.
But look again, May. See how these wings are veined, and do you not remember how you admired the silvery wings of the corydalus when we spread them out?
Yes, it belongs to the same order as the corydalus.
The name of the insect order to which they both belong is Neuroptera, fromneuron, a nerve, andpteron—who remembers whatpteronmeans?
Yes, a wing. Nerve-winged.
What does that mean?
It means that the wings are crossed by many nerves or veins. Yes, that is what gives them their lacelike appearance.
Pretty golden eye, why do we not oftener see you on the trees and bushes? It is only by accident we found you to-day, down in the grass.
The truth is, this pretty fairy hides by day and comes out at night to lay its eggs. Like the May fly, the adult lacewing does not eat. It is a helpless little beauty, though it has one powerful means of defence, as you will discover if you touch it.
Ah, yes; you have already detected it! It gives forth such an offensive odor that nothing, one should think, could have the hardihood to eat it.
May says she supposes the larva of the lacewing is a little monster like that of the corydalus.
But you will not expect to find it as large as a dobson.
I think if we hunt about a little, we can find one.
Here is one on the leaf. See what a little fellow! And how fast it runs!
Fairy Lacewing
We shall have to take it captive, in order to get a chance to see it.
It is a funny little larva, with jaws that aretre-men-dousfor one of its size.
Why do you suppose it has such jaws?
May says, for the usual reason, to eat up other larvæ.
Yes; but wait till I tell you another name for this larva.
It is also called the aphis lion.
Aphis, you know, is the same as aphid, or plant louse. In other words it is the plant-louse lion.
Ah, yes; you are quite willing it should devour the aphids.
And it does. It is very fond of them, though it will also devour any unlucky insect it is strong enough to overcome.
It has a terrible appetite, this child of the pretty lacewing.
It would even eat its brothers and sisters before they hatched out of the egg if it could get at them.
The pretty lacewing knows what an appetite her ever hungry larvæ will have, and so she protects them against each other.
Clever little mother! she lays the eggs in such a way that the larvæ that hatch out first cannot devour the rest of the eggs.
How do you think she manages it?
Here are some of her eggs on this leaf.
Yes, John; each one is on top of a slender stalk.
The stalk is of stiff silk.
There they are, like a little forest, with an egg for each tree top.
Fairy Lacewing
When an egg hatches the young aphis lion drops down to the leaf and runs about like a ravening lion seeking some living thing to devour.
Above his head, quite unsuspected by him, are the eggs out of which his brothers and sisters have not yet hatched.
What a feast he could have if he knew about it!
And what a sad little cannibal he would be!
The larva of the aphis lion has no distinct thorax. Its legs are attached to the upper segments of the body, and its metamorphosis is like that of the corydalus.
When about to become a pupa, it makes for itself a little covering of white silk. Here it lies quite motionless and undergoes the final transformation.
Yes, its metamorphosis is complete.
It bites an opening through its silken walls, and out steps—not the hungry, little, all-devouring aphis lion, but this elegant lady with her pale-green lacelike wings and her large, golden eyes.
You see the aphis lion is our very good friend.
It helps us get rid of the aphids, and we should never kill a lacewing or a child of the lacewing.
John has found something he wants us all to see.
We will go with him.
Now we will sit down on this sand bank and look at what he has to show us. See! those smooth little funnels in the sand.
The Ant Lion
Those are what we have come out to see.
Let us watch them a while.
Mollie says an ant is walking close to the rim of the funnel she is watching. Now the ant slips over the edge and slides down the smooth sides of the funnel.
And see! from the bottom of the funnel leap out two curved jaws and—good-by, ant!
The ant has been dragged down out of sight through a hole in the bottom of the funnel.
What a strange proceeding!
Who can be living down there at the bottom of the funnel?
We are sorry to disturb such a pretty piece of work,but we shall have to dig out one of the funnels. We shall have to be quick, too.
There, there, under the trowel! No, it is gone. There it is again. Dig fast, Ned. That is right. He has put it with a trowelful of sand into our box.
We will gently shake out the sand until we uncover it.
Mabel says it is just what she thought it was—a larva.
Yes, it is a larva.
The Ant Lion
You see it looks a little like the lacewing larva, and it, too, belongs to the Neuroptera.
What jaws!
How do you suppose it makes its tunnel?
If we give it plenty of sand, and keep very quiet, perhaps it will go to work.
There! it is throwing the sand about.
May says it is using its own head as a trowel. Yes, it is shovelling the sand away with its head.
Why is Ned laughing? Oh, see the ant lion he is watching! An ant slid part way down its funnel and tried to climb out again, and the ant lion down below is flinging sand at it.
There! it has succeeded in making the poor ant slip; down it goes, and now the ant lion has seized it and dragged it down under the ground.
It is easy to find these pit-falls of the ant lion in sand banks in the summer-time.
Yes, May, the ant lions eat many ants, and they moult and grow, and, finally, they, too, make a little cocoon about themselves.
Yes, the little silken room they weave we call a cocoon, but the ant lions make theirs of silk and sand.
The Ant Lion
Within the cocoon they become motionless pupæ, and finally appear as silver-winged little creatures that bear no resemblance to the large-jawed, ever hungry, ant lion.
May says she thinks the Neuroptera differ from all the other orders in the way the larvæ transform.
That is true, May, they do.
In no other order that we have studied do the insects go into the pupal state to undergo the final transformation.
Who remembers what the young of insects that undergo an incomplete metamorphosis are sometimes called?
Dear me, you all remember!
Yes, the young are sometimes called nymphs.
The nymphs do not change into pupæ.
The young grasshoppers do not change into motionless pupæ, they just keep on growing until they are perfect adults.
Young grasshoppers are sometimes called nymphs instead of larvæ.