The Project Gutenberg eBook of An Elementary Study of Insects
Title: An Elementary Study of Insects
Author: Leonard Haseman
Release date: November 10, 2007 [eBook #23434]
Language: English
Credits: Produced by Chris Curnow, Joseph Cooper, Stephen Blundell
and the Online Distributed Proofreading Team at
http://www.pgdp.net
AN ELEMENTARY
STUDY OF
INSECTS
By
LEONARD HASEMAN
Professor of Entomology in the University of Missouri
Columbia, Missouri
MISSOURI BOOK COMPANY
1923
CONTENTS.
- Chapter I Insects:
- (1) What they are.
- (2) Their principal characteristics.
- (3) Their methods of developing.
- (4) The principal orders.
- (5) Their habits.
- (6) Their role in agriculture.
- Chapter III The Grasshopper:
- (1) Brief discussion of the grasshopper.
- (2) Field studies.
- (3) Breeding cage observations.
- (4) Study of specimen.
INTRODUCTION
In the preparation of a book of this nature, to be used in the grade schools, we realize that the one fundamental thing to keep in mind is the economic importance of the insect, be it good or bad. The child wants to know what is good and what is bad and how he can make use of the good and how he can get rid of the bad. And yet there is something more associated with the life, work and development of each tiny insect. There is a story—a story of growth, not unlike that of the developing child, a story of courage, strife and ultimate success or failure, which is as interesting and of greater value to the child than many of the stories of adventure and of historical facts. Snatches of these stories will appear in the following chapters along with the studies on insects and their economic importance.
In the development of our grade school system, especially in the rural districts, there is a growing demand for some practical work along with the regular cultural studies. To the child in the rural schools, practical knowledge naturally tends toward agriculture. Many of these boys and girls do not have a chance to pursue studies beyond the grades and it therefore becomes necessary to introduce some elementary agriculture into the grades to supply the natural craving of this vast assemblage of children in the rural schools of our land.
In the search for a study which will give unlimited scope for independent thought and observation and which will lead the child to understand better the forces of nature that affect agriculture, nothing is so readily available and attractive to the child as nature study, an elementary study of the natural sciences. In fact agriculture is primarily a course in nature study where we study how plants and animals struggle for existence.
There is a period in the life of every child when he is especially susceptible to the "call of the fields;" when he roams through woods or by shady brooks gathering flowers, fishing for mud-cats and cleaning out bumble-bees' nests. It is often compared with the life of the savage and is merely the outward expression of an inward craving for a closer relation with nature and her creatures. If one can reach a child while at that age he has a ready listener and an apt pupil. That is the time to guide and instruct the child along the line of nature study.
The most important questions confronting the average teacher in the grade schools are: "What material shall I use and how shall I proceed to direct the child along this line?" First of all use that material which is most readily available, which is most familiar to the child and which will attract and hold his attention. There is nothing so readily available and so generally interesting to both boys and girls as are the thousands of fluttering, buzzing, hopping and creeping forms of insects. They are present everywhere, in all seasons and are known to every child of the city or farm. They are easily observed in the field and can be kept in confinement for study. Many of them are of the greatest importance to man; a study of them becomes of special value.
In pursuing a study of nature and her creatures one should go into the woods and fields as much as possible and study them where they are found. In this way one can determine how they live together, what they feed on and the various other questions which the inquisitive mind of a healthy child will ask. When field work is not possible, gather the insects and keep them alive in jars where they can be fed and observed. Some forms cannot be kept in confinement and in such cases samples should be killed and pinned, thereby forming a collection for study.
Most of the forms which are included in the following chapters can be kept in confinement in glass jars or studies out doors. The studies have been made so general that in case the particular form mentioned is not available any closely related form can be used. Each child should make a small collection of living and pinned insects for study and should be encouraged to observe insects and their work in the field. The collections and many of the observations could be made to good advantage during the summer vacation when the insects are most abundant and active.
Pupils should not be encouraged merely to make observations, but they should be required to record them as well. Brief descriptions of the appearance and development of insects, the injury they do, and remedies for the same, will help fix in mind facts which otherwise might soon be forgotten. Drawings, whenever possible, should also be required. The pupil who can record observations accurately with drawings will not soon forget them. The teacher should therefore require each pupil to provide himself with a note-book for keeping brief, but accurate notes and careful drawings. The drawings should be made with a hard lead pencil on un-ruled paper, the size of the note-book, and the pupils should be encouraged to be neat and accurate.
The author wishes to take this opportunity of expressing his deep appreciation for the many helpful suggestions and other assistance which Mr. R. H. Emberson, superintendent of Boys and Girls Club Work in Missouri, has given. It was his life-long devotion to the boys and girls of the grade schools and his keen appreciation of their needs that lead him first to suggest to the author the importance of preparing this little book for their use.
University of Missouri.
"The study of entomology is one of the most fascinating of pursuits. It takes its votaries into the treasure-houses of Nature, and explains some of the wonderful series of links which form the great chain of creation. It lays open before us another world, of which we have been hitherto unconscious, and shows us that the tiniest insect, so small perhaps that the unaided eye can scarcely see it, has its work to do in the world, and does it."
Chapter I
INSECTS
"There is a difference between a grub and a butterfly; yet your butterfly was a grub."
In undertaking a study of insects it is well first of all to know something about what they are, their general nature, appearance, habits and development. The insects comprise the largest group of animals on the globe. There are about four times as many different kinds of insects as all other kinds of animals combined. Insects vary greatly in size. Some are as large as small birds, while others are so small that a thousand placed in one pile would not equal the size of a pea.
Insects are commonly spoken of as "bugs." This term, however, is properly used only when referring to the one order of insects which includes the sap and blood-sucking insects such as the chinch bug, bed-bug, squash bug, and the like. Then too, there are many so-called "bugs" which are not insects at all. Spiders, thousand-legs, crawfishes and even earth-worms are often spoken of as bugs.
What They Are
Insects are variously formed, but as a rule the mature ones have three and only three pairs of legs, one pair of feelers, one pair of large eyes, and one or two pairs of wings. The body is divided into a head, thorax and abdomen. The head bears the eyes, feelers and mouth, the thorax bears the legs and wings, and the abdomen is made up of a number of segments. The presence of wings at once decides whether or not it is an insect, for, aside from bats and birds, insects alone have true wings. These are the distinguishing characters of the full grown insect, but, like birds, they hatch from eggs and while young do not always look like their parents. When young they may take on various shapes as caterpillars, borers, maggots, grubs, hoppers, and the like. Young insects are often difficult to distinguish from true worms, centipedes, snails, and such forms, but after one has collected and reared some of the young and watched them pass through the different stages and emerge with wings they are much more easily recognized.
Their Principal Characteristics
Young insects as a rule are soft like caterpillars and maggots, while the old ones usually have a hard body wall, similar to the beetles and wasps. The wings are usually thin and transparent though in some cases they are leathery or hard as in case of beetles or covered with scales as in the butterflies. The three pairs of legs are jointed and used for running, climbing, jumping, swimming, digging or grasping. The feelers or antennae are usually threadlike, clubbed, or resemble a feather and extend forward or sidewise from the head. The large eyes are compound, being made up of many great small units which, when magnified, resemble honey-comb. In some cases two or three small bead-like eyes may be present besides the two large eyes. The mouth parts of insects may be formed for chewing, as in the grasshopper, or for sucking up liquids, as in the mosquito. The mouth of an insect is built on an entirely different plan from our own. Chewing insects have an upper and lower lip and between these there are two pairs of grinding jaws. These jaws are hinged at the side of the face and when chewing they come together from either side so as to meet in the middle of the mouth. They therefore work sidewise rather than up and down. The mouth parts of the sucking insects are drawn out to form a sucking tube or proboscis as in case of the butterfly or mosquito.
The internal organs of insects are similar to those of other animals. The digestive tube consists of oesophagus, gizzard, or stomach, and intestines. The nervous system is well developed as shown by the extreme sensitiveness of insects to touch. The brain is comparatively small except in the bees and ants. The circulatory system consists simply of a long tube heart, the blood vessels being absent. In this way the internal organs of the insect are simply bathed in the blood. The system of respiration is most complicated. The air is taken in through pores usually along the side of the body and is then carried through fine tracheal tubes to all parts of the body. You cannot drown an insect by putting its head under water, since it does not breathe through its mouth. The muscular system is similar to that of other animals which have the skeleton on the outside.
Their Methods of Developing
In most cases the parent insect deposits small eggs which hatch later into the young insects. In some cases, as with the blow-flies, the maggot may hatch from the egg while yet in the parent's body, when the active larva is born alive. Whether the egg hatches before or after it is deposited, the young insect continues to develop in one of three ways. It may resemble the parent and simply grow as does a kitten, or it may look somewhat like its parent though smaller and without wings, as the young grasshopper, or it may bear no resemblance whatever to the parent, as the caterpillar which feeds and grows and finally spins a cocoon in which it passes to the resting chrysalis stage and later emerges with wings. The development of insects is therefore extremely complicated.
The Principal Orders
In order to study a group of animals which includes so many thousand different kinds it is necessary to divide them into a number of sharply defined divisions or orders. All animal life is naturally grouped into such divisions and subdivisions. Among the insects we at once detect seven large, sharply defined divisions or orders, and ten or more smaller ones. Of these we have first, the two-winged true flies; second, the four-winged butterflies and moths; third, the hard-backed beetles; fourth, the stinging four-winged wasps and bees; fifth, the variously formed sucking insects or true bugs, as chinch bugs and bed-bugs; sixth, the rapid-flying four-winged snake doctors or dragon-flies and, seventh, the hopping forms, the grasshoppers. Besides these we have the various smaller orders of water-loving insects, fleas, etc. The seven groups mentioned above include the majority of our common forms and in the studies to follow we will include only representatives from these orders.
Their Habits
The habits of insects are as varied as their forms and adaptations. Some live in the water all their life, others spend a part of their life under water, others live the care-free life of the open air, others enjoy feeding upon and living in the foulest of filth, others associate themselves with certain definite crops or animals thereby doing untold injury, while others produce food and other materials which are to be used by man for his comfort. Every imaginable nook and crook, from the depths of lakes to the tops of mountains, from the warm, sunny south to the cold frigid north, from the foul damp swamps to the heart of our desert lands, offers a home for some small insect.
The most striking habits and developments among insects is found in the more highly advanced families of bees and ants where definite insect societies are formed, resembling in many respects human societies and human activities. Among these villages are established, homes built, battles fought, slaves made, herds kept by shepherds, and even fields cultivated. In these groups we have the nearest approach to human intelligence.
Their Role in Agriculture
Some insects may be very destructive to crops, others are beneficial, while the majority of insects are of no importance to man or agriculture. The various forms of pests such as the chinch bug, potato beetles, and others do an enormous amount of damage each year. They destroy hundreds of millions of dollars worth of crops annually in the United States alone. They devour enough to pay for the entire cost of running the school system of our country and nearly enough to meet all the expenses of our government. In view of these facts it is the duty of each and every farmer, young or old, to acquaint himself with these destructive pests and prepare himself for combating them. With a knowledge of the methods of controlling these pests much of this enormous loss can be prevented.
While some insects are extremely injurious, others are very helpful. The products of the honey bee in the United States alone amount to several million dollars a year, to say nothing of its value to the farmer in pollinating fruits. The annual output of silk, all of which is spun by the silkworm, is worth millions of dollars. Many other forms are of value to man by producing material of commercial value such as lac, shellack, dyes, medicines, etc. Of all the beneficial insects those which are of greatest value to man are the parasites and similar forms which help to keep in check many of the severest pests of the farm. Insects are not all bad fellows by any means. One must acquaint himself with those which are good and those which are bad before he can hope to deal with them intelligently.
We behold those tender wings expand,
Emblems of our own great resurrection,
Emblems of the bright and better land."
Chapter II
COLLECTING INSECTS
To stick a pin into an insect?"
In the life of every normal human there comes a time when he wishes to make a collection of some kind. It may be a collection of coins, postage stamps, post-cards, shells, relics, birds' eggs, pressed flowers or insects. If the child grows up in the country, the result of this craving is usually three or four cigar boxes of insects or an almanac or geography stuffed with the most attractive wild flowers of the field. A collection of this sort may be small and poorly kept and yet it is worth while. In later life one will search in his mother's closet or attic for the old cigar boxes which contain the remains of youthful efforts, usually a mass of gaudy wings, fragments of insect legs and bodies and a few rusty pins. This desire to make a collection is natural and should be encouraged in the child. It tends to make him observe closely and creates an interest in things about him, and if properly directed it will add a store of information which can be gotten in no other way.
Directions for Collecting
Many boys and girls of the rural schools will have little time or inclination to provide themselves with apparatus for collecting insects. An old straw hat or a limb will serve their purpose. From their point of view what difference does it make if they tear off most of the legs and break the wings? They succeed in securing the "bug" and when pinned in the box it will mean just about as much to them as the most perfect specimen ever prepared.
This method of catching insects will prove effective where nothing better is available, but any child can easily make a small insect net by attaching a loop of fairly stiff wire to a broom handle or other stick and sewing a bag of mosquito netting or other thin cloth to the wire. By means of such a net one can catch insects more easily and at the same time there is less danger of tearing such insects as butterflies. Care must be taken in handling the stinging insects.
The country boy and girl will have little trouble getting hold of insects, but they are often puzzled when it comes to killing them. It seems cruel to pin up an insect alive and have it squirm for a day or two and some means of killing them should be devised. Most of the soft insects, such as flies, butterflies, etc., can be killed by pressing their body, in the region of the wings, between one's thumb and forefinger. Such forms as beetles and wasps can be quickly killed by dropping them into coal oil or a strong soap suds. Any method which can be devised for quickly killing the insect, and which will not seriously mutilate it, can be used.
A convenient killing bottle can be made by sealing a few small lumps of the deadly poison, potassium or sodium cyanide, in the bottom of a strong, wide-mouthed bottle, with plaster of Paris; or a few drops of chloroform or ether on a wad of cotton in a similar bottle, will also serve as a convenient killing jar.
Pinning and Preserving a Collection
After the insects, have been caught and killed, they should then be prepared for the permanent collection. Most insects such as wasps, beetles, flies and grasshoppers should simply have a pin thrust through their bodies until they are two-thirds the way up on the pin and then put them away in a box. Such forms as butterflies and moths make a much better collection if the wings are spread so as to bring out their gaudy markings. In order to spread butterflies' wings, one needs a spreading board, which can be made in ten minutes by taking a pine board two feet long, and six inches wide and on this nail two strips an inch thick, so that there is a crack between them. The crack should be half an inch wide at one end and a quarter of an inch wide at the other end, and in the bottom of it press strips of cornstalk pith so as to have something soft in which to stick the pins. After a pin has been stuck through the body of a dead butterfly between the wings, it is then pinned in the crack so that the back of the butterfly is on a level with the strips. Then the wings are drawn forward until they stand straight out from the body when they are pinned down by means of strips of paper and left to dry a few days until they become perfectly rigid. In this way a most beautiful collection can be made very easily, but where time and materials are not available, simply pin them up like other insects, leaving the wings to hang as they will. After the specimens are pinned they should be put away in cigar boxes in the bottom of which is pinned or pasted a layer of cork or corrugated paper similar to that which comes between glass fruit cans. These make ideal cases for keeping small collections as the odor of tobacco helps keep pests from getting in to destroy the collection.
Rearing and Observing Them While Alive
While studying an insect it is advisable wherever possible to first study it where it is found in the field and later bring it home and keep it alive in a jar where it can be fed and observed and its various habits studied. Cages for breeding insects consist simply of a few glass fruit cans and jelly glasses with tin or cloth covers. A child can borrow one or two of these from his mother's fruit cellar. A layer of moist sand or soil should be put in the bottom of the jar to provide a retreat for those forms which go into the ground before changing to adults. Before an insect is placed in one of these breeding cages its food plant should be determined by observations in the field, and every day or two a fresh supply should be gathered. Most of the forms discussed in the following chapters can be kept in jars and reared to the adult stage. Rearing insects is both interesting and instructive. Every child should be given an opportunity to rear a few forms either during the school year or during the summer vacation.
To stray into Butterfly Vale,
Where my wondering eyes beheld butterflies
With wings that were wide as a sail.
They lived in such houses of grandeur,
Their days were successions of joys,
And the very last fad these butterflies had
Was making collections of boys.
Pinned up on their walls. When I said
'Twas a terrible sight to see boys in that plight,
I was answered: 'Oh, well they are dead.
We catch them alive, but we kill them,
With ether—a very nice way:
Just look at this fellow—his hair is so yellow,
And his eyes such a beautiful gray.
As black as the clay at our feet;
He sets off that blond that is pinned just beyond
In a way most artistic and neat.
And now let me show you the latest,—
A specimen really select,
A boy with a head that is carroty-red
And a face that is funnily specked.
Those spots bar him out of each class;
We think him a treasure to study at leisure
And analyze under a glass.'
I seemed to grow cold as I listened
To the words that these butterflies spoke;
With fear overcome, I was speechless and dumb,
And then with a start,—I awoke!"
Chapter III
THE GRASSHOPPER
The grasshopper or locust is one of the most ancient plagues of cultivated crops. From the earliest time they have destroyed crops. During Moses' sojourn in Egypt they were so destructive as to cause severe famine and various other references to their destructive work are to be found in the early writings. Since those early days, just think of the crops that have disappeared between the greedy jaws of grasshoppers!
In our own country it has not been many years since the sun was darkened for days by clouds of grasshoppers as they settled down from the Rocky Mountains upon the growing crops in the neighboring states. One day a field might have a promising crop and by the next day it might be left as bare as a dry stubble field in August. Those days of great destruction in America have largely passed but each year the active jaws of "hoppers" devour a handsome fortune.