Perhaps this account may be followed with some difficulty; let us,

therefore, take a single facet, and trace it to its termination. Each

facet being in fact a distinct eye, we shall be able, in so doing, to

get a clear comprehension of the whole organ, which is after all only

made up of a large number of these distinct eyes. Separating, then,

one facet from the rest, we find this single eye to consist of several

portions: 1. the six-sided facet; 2. the cone-shaped cylinder, clear

and transparent; 3. a delicate fibre of nerve connected with the bottom

of this cone; and, 4. the large nerve itself. The diagram on the next

page will make this perfectly intelligible.

But it may be asked, What of the colouring matter? It exists in three

places. 1. The first layer surrounds the cones (2), and separates them

from one another, and from the nerve below in part. 2. The second

layer surrounds the nerve fibres (3). And, 3. the last layer is at the

junction of the nerve fibre (3) with the nerve itself (4).

This apparently complicated mechanism well deserves the reader's

attention; nor should the subject be quitted until it is clearly

understood. We are unable to enter into further particulars upon

the structure and functions of this beautiful apparatus; but it must

be added, that the following is the manner in which the ray of light

becomes perceived by the insect. It first passes through the facet

(_a_), next enters the cone (_b_), then strikes upon the nerve (_c_)

which conveys the impression, taking the large nerve (_d_) to the

brain. The colouring layers are intended to prevent any rays of light

from passing to other parts of the insect's eye, and so confusing the

impressions made upon its senses by external objects.

[Illustration: _A single facet separated, and magnified._]

The number of these facets, or, if we choose to call them so, distinct

eyes, varies in different insects. In some there are comparatively few,

in others an amazing multitude. The following list of their number is

given by Müller, as observed by various entomologists:--

In the Ant there are 50

" Convolvulus Sphinx 1,300

" Common House-fly 4,000

" Silk-worm Moth 6,236

" Goat Moth 11,300

In the Dragon-fly 12,544

" Butterfly 17,355

" Mordella 25,088

According to the calculations of another author there cannot be fewer

than 34,650 in the compound eye of a butterfly. Amazing thought! each

of this immense host is considered to be a separate eye, receives

separate impressions of light, and has a separate structure and

organization, both perfect in their kind.

It is not difficult to remove the compound eye of an insect; and in

so doing it will be found that each lens is as clear as crystal. The

ingenious Réaumur actually succeeded in removing one and adjusting it

to a lens; and he found that he could see through the insect's eye

very distinctly, only he says the surrounding objects appeared to be

greatly multiplied. There is a common optical toy which is ground into

a number of facets which communicates this appearance to objects when

seen through it, and thus furnishes us with a good illustration of the

endless confusion of images which would have perplexed the insect, had

not the various beautiful contrivances of which we have spoken been

adjusted to prevent it.

But we must guard against a very natural mistake which might arise upon

the subject of the eyes of insects from supposing them in any degree

comparable to those of higher animals as regards their motions. When

man, or an animal, wishes to look at any object, they do so by causing

several muscles to be brought into action which move the eyes round so

as to receive the rays of light from the particular point where this

object is placed; and so admirably arranged is the mechanism by which

these movements are effected, that they are as well provided for all

the purposes of sight with two eyes as with twenty. In insects no such

apparatus exists; the eyes are quite immovable; they are, in fact, set

in the head like a gem in a lady's ring, and are altogether removed

from the control of the insect. In order to obviate the annoyance and

inconvenience which would result from this arrangement, their eyes are

formed on the wonderful principles already mentioned, and, instead of

insects being furnished with two eyes, they are provided with many

thousands! They are thus enabled to enjoy not only the same extent and

range of vision with ourselves, but even a much larger.

Insects are also furnished with a contrivance by which they can see

objects at a little distance, and objects at a great distance--it

may be at the same time; which is more than can be strictly said of

ourselves. In men and animals there is a very exquisite apparatus

arranged within the eye, by means of which it can accommodate itself to

objects close at hand, or again to others at the greatest distance. We

can see at one moment a pin at our feet, and at the next the summit of

a hill some thirty or forty miles off. Now the laws of light are such,

that, to effect this properly, we must have some apparatus in the eye

to arrange its focal capacity, so as to receive and concentrate the

lines of light proceeding from such different points as the distance of

a few inches, and that of many miles. What this apparatus may be is not

as yet very satisfactorily determined. But in insects the same result

is obtained by a very curious provision.--_Some of their eyes are

short-sighted, and some long-sighted._ The simple eyes are supposed, by

Professor Müller, to be the short-sighted eyes, and the compound eyes

the long-sighted ones.

The number of _compound_ eyes in insects does not often exceed two,

these being made up, it will not be forgotten, by multitudes of single

eyes. But in a few, whose habits require that they should be endowed

with extraordinary means of vision, there are as many as four. If the

reader would betake him to the brook-side, and creep noiselessly along

its margin some summer afternoon, until he comes to a quiet glassy pool

where the water seems to have forgotten itself and fallen asleep, so

still, so silent, and so smooth does it lie, reflecting all the lustre

of the deep-blue sky overhead, he will surprise a dancing party of

insects busy waltzing at a wonderful rate, now skimming hither, now

shooting across the glassy pavement on which they sport, now joining

together and wheeling round and round, and again, as the king-fisher

comes fluttering down the river as though on some errand of immense

importance, breaking up their party and flying into a thousand holes

and corners to wait until all is quiet. Let him exercise his activity

and patience, and catch one of these giddy insects, which are known to

entomologists by the name of the _Gyrinus Natator_, and he will have

a good example of an insect provided with four compound eyes, so that

it can see not only before and behind, but upward into the sky, and

downward into the clear cool waters on whose surface its happy life is

spent. Some insects, like Cyclops of old, are furnished only with one

eye; and some, it is said, are quite blind--creatures that never feel

the blessed influences of the pleasant sunlight. Like the simple eyes,

the compound eyes are sometimes fixed on the end of a little footstalk,

so as to give the insect somewhat the appearance of being furnished

with a pair of opera glasses, or short telescopes.

In order to ascertain by what means the bee found its way to the hive,

whether by seeing it through its compound eyes, or otherwise, Réaumur

performed an interesting experiment similar in character to the one

before mentioned. He covered with a red varnish, which was quite

opaque, the compound eyes of a number of bees taken from the same hive.

He then shut them up in a box with several other bees from the same

hive which he left untouched. The box was only a few paces distant

from the hive from which the bees were taken. He then opened the lid

of the box, and those which had not been blinded instantly flew out of

it, and entered their habitation. Those whose eyes had been varnished

appeared not to care to leave the box at all, and seemed very unwilling

to make any attempt to fly; some of them, indeed, flew about from one

side to another, but did not go far. Réaumur then threw several of them

up into the air, and they immediately began to soar higher and higher,

until at length they went out of sight altogether! Réaumur compares

the poor insect's manoeuvres to those of a crow, whose head and eyes

mischievous boys have covered with a paper bonnet: the bird flies

upward until its strength is exhausted, when it drops again to the

earth. Not only did those bees which he threw up into the air thus soar

until they were lost to view, but all the most active of those which

were left in the box did so likewise, and Réaumur saw them no more. Not

one could find its way to the hive. From this experiment, and from the

preceding one, it is evident that both the compound and the simple eyes

are necessary to enable the insect to see perfectly; for when either

was varnished over, the bees could not find their way to their home

again. Réaumur imagines that the cause of the wheeling flight of bees,

sometimes observed, now in this direction, now in the opposite, may

arise from their eyes becoming perhaps in part obscured by the pollen,

or yellow powder of the flowers into which they plunge, the bee thereby

becoming partly blind-folded. These experiments are so interesting that

they deserve repeating, and it might be tried whether the result would

be different if only one eye were blinded. Other variations of the

experiments will also suggest themselves.

Although not organs of sufficient size to give their colouring the

requisite distinctness and amount of surface which would render it

very conspicuous in our estimation, the eyes of insects are often

exquisitely beautiful, and vie almost with precious stones in lustre.

Their most common colour is black, or brown; but the eyes of many

flies glow with fiery colours, some banded with green and purple, some

variously figured black and red. Some again glitter like burnished gold

shaded with the softest green; and some blaze with a play of colours,

like the diamond set in jet. The eye of the dragon-fly, in particular,

is a lustrous crystalline object of extreme beauty.

[Illustration: _Peacock Butterfly._]

We have dwelt as long as our limits will permit on this wonderful

apparatus of vision in insects: let us now turn our thoughts for a

little space to a pair of organs which are, perhaps, of all others the

most characteristic of the insect tribes: these are the _Antennæ_. We

need scarcely explain what these are, or point them out to the reader,

since they are so familiar to most persons, but under the erroneous,

or, at any rate, the questionable expression--"the feelers." We have

an excellent specimen of _antennæ_ in those of the butterflies, in

which insects they are very long and elegant organs. They are attached

to the head by means of a beautiful joint, called a ball and socket,

the same as is often adapted to garden watering engine-pipes, so as to

enable them to be moved about in all directions. They are never found

absent in the perfect insect, and are manifestly organs of considerable

importance in the insect economy. As to their structure,--when

examined under a microscope, antennæ are found to be composed of a

variable number of small round pieces, covered with a horny or leathery

skin, but within being softer and hollow, so as to form a series of

tubes placed end to end, all connected together in such a manner as

to admit of free movement between each joint, so that the insect can

bend them into any shape it may find expedient for its purposes. But

it must not be supposed that all antennæ are similar in form, or there

would be a risk of their being continually mistaken by the reader for

some other organ. The cut on the next page will, at a glance, exhibit

the astonishing variety of form assumed by these organs. The common

cockchafer is possessed of antennæ as strikingly different in form from

those of the butterfly, as if they were really distinct organs intended

and adapted to serve different purposes. Some are long and thread-like,

some resemble a necklace of pearls, some are notched like a saw, some

have a resemblance to a fan, some are like a club, some resemble a

fork, and some a feather; in short, their variety of form is almost

endless: and they differ as much in length and in thickness; for while

the antennæ of some insects are as long as, or even longer than, their

bodies, those of others are very short, and little prominent; and while

some are as thin and fine as the finest hair, others are nearly as

thick as the true body of the insect. Let us now ask what is the use of

these singular organs of the insect?

[Illustration: _Various Antennæ._]

From a hint which has before been dropped, it is probable that the

answer to this question will be readily anticipated. Various facts

appear to show that they may be the insect's _ears_! "Can it be that

such is their function?" some may exclaim, calling to mind that ears

in other creatures are so different in appearance and structure from

these organs. There have been many opinions on the subject, and some

have maintained views completely opposed to this idea. But the greater

number of entomologists seem to consider this as their most probable

function. If they are not ears, we are not able to point to any other

organs in the head which are. From a number of facts it is certain,

that insects can hear; from which it is equally certain, that they

must possess special organs. We may, therefore, until the contrary is

shown with respect to them, fairly be allowed to consider the antennæ

as these organs. The opinions of Messrs. Kirby and Spence on this point

are conveyed in the following words:--"They conceive that antennæ

by a peculiar structure may collect notices from the atmosphere,

receive touches or vibrations, and communicate them to the sensorium

(or brain), which, though not precisely to be called hearing, may

answer the same purpose." The late celebrated Dr. W. F. Erichson of

Berlin, by means of the microscope, has discovered in all insects, and

especially in those most remarkable for their powers of smelling, that

these organs are furnished with a number of fine pores, clothed with

membrane, which he regards as organs of smell.[U]

Every one has heard of M. Pelisson, the prisoner at the Bastile, and

his spider companions of the cell. This gentleman had, by patient

training, engaged the attention of a spider, which used every day to

come and listen to a solo on his violin, after which it would make its

retreat again to its home. Now it is clear, that this little insect not

only heard, but even enjoyed, the notes of his instrument; which would

have been impossible, had it possessed no ears. Then again, every one

must have noticed the start which a fly will make if some sharp noise

be made near it, and how actively it will move its legs, and seem to be

put all on the _qui vive_. A little every-day observation will furnish

us with many similar instances. "A little moth," writes one of the

last-mentioned authors, "was reposing on my window; I made a quiet,

not loud, but distinct noise; the antenna nearest to me immediately

moved towards me. I repeated the noise at least a dozen times, and

it was followed every time by the same motion of that organ; till at

length the insect, being alarmed, became more agitated and violent

in its motions. In this instance it could not be _touch_; since the

antenna was not applied to a surface, but directed towards the quarter

from which the sound came, as if to listen." Can we question that the

merry grasshopper, chirping all day in the field, is heard by its mate?

or that the cricket on the hearth sings for its fellows, or only to

please _our_ ears? or does the tap of the death-tick beetle, formerly

commemorated, draw forth no answering tap from its companion on the

other side of the post? All these instances, and countless more that

might be mentioned, indicate, beyond a question, that insects have the

faculty of hearing, and render it extremely probable that the antennæ

are the organs by which this function is performed.

But it is probable that they serve another and not less important

purpose. The country folk, who are generally very weather-wise, and

whose sayings always deserve a great deal of attention, because

they are very commonly founded both upon observation of facts, and

experience, will always assure us that the high flight of swallows in

their search after insects is a certain token of fair weather; their

low flight of approaching wet. Why is this? Can insects foretell the

state of the weather? and if so, by what means? That insects have a

meteorometrical power of foretelling the state of the weather, appears

beyond a doubt. To select a few instances. Bees, our exemplars in so

many points, might be consulted with advantage, and would often give

us better information as to whether an over-coat or an umbrella would

be probably required, than the not always trustworthy barometer. When

engaged in their daily labours, if a change of weather to rain is at

hand, although the sun may yet shine and the sky remain clear and calm,

they foresee it, and return suddenly to their hives. Hence in weather

of an unsettled description they never undertake journeys far from

home, but make short excursions to and from their hives, being never

absent long at a time; and if we find a bee wandering far from its

hive, it may be taken, on the other hand, as a pretty sure prognostic

that top-coat and umbrella may be left at home for _that_ day at

least. Ants, as we have already noticed, possess the same faculty of

weather-wisdom, never allowing their larvæ to be caught in a shower.

The abundance of insects in our houses in wet weather, is a familiar

observation; we are assured that in hot countries their excessive

numbers, during the rainy season, make these little creatures almost

as terrible as a plague to all who are within--climbing up the walls,

scrambling into the dishes, drowning themselves in the soup-tureens, or

putting out the lights with their bodies. In hot and sultry weather,

when a black cloud or two in the far horizon give token of a coming

storm, insects abound in the air; but as the heavens grow black, they

disappear; and before a drop of rain has actually fallen, we may look

in vain for them.

That the antennæ are the organs by which this knowledge of coming

events with regard to the weather is obtained by the insects, appears

probable. They may, perhaps, perceive by their delicate surfaces,

changes in the _electrical_ condition of the air, which are quite

insensible to ourselves: and as all change of weather is preceded and

accompanied by changes of electrical balance of one kind or another

in the air, they may be thus forewarned of the coming danger. The

following is the manoeuvre of a large number of insects of the beetle

tribe. When they are about to move from any station where they have

been at rest, the first thing they usually do before they move a step,

is to bring forward and expand their antennæ, which have previously

been folded up out of the way. They open them as widely as possible,

so as to expose them to all the influences of the air, and then, if

they be satisfied, they unfold their wings and take their flight. We

might compare this proceeding with that of one of ourselves looking

up at the direction of the wind, or tapping the weather-glass in the

hall, previous to setting out for the day! Too much stress, however,

it must be added, is not to be laid upon this point; for while it is

unquestionable that insects have knowledge of the weather, it is of

course very difficult to ascertain with certainty whether it is by

means of their antennæ, or by the general feeling of their bodies;

analogous, perhaps, to what rheumatic persons feel when the wind goes

round to the _north-east_.

There is a still more singular use of the antennæ, which deserves to

be mentioned. These organs appear to be the principal instruments

of _speech_, if we may use such a term, or, at any rate, of the

communication of intelligence. When the soldier ants go out upon their

expeditions, and have left the nest, previously to setting off, they

touch each other with their antennæ and forehead on the trunk; and this

is their signal for marching, for as soon as ever a soldier feels this

tap, he immediately puts himself in motion. When, also, they have any

discovery to communicate, they strike with them those that they meet,

in a particularly impressive manner; and if a hungry ant wants to be

fed, it touches with its two antennæ, moving them very rapidly, those

of the individual from which it expects its meal. They appear to salute

one another by gently tapping each other's antennæ, as we should shake

hands on meeting an old friend!

M. Huber has related an account of some interesting experiments of

his on a hive of bees, which strikingly proves that the antennæ are

really organs for the transmission of intelligence. He wished to

ascertain whether, when they had lost a queen, they discovered the

sad event by their smell, their touch, or any unknown cause; for such

a loss, in the course of a single hour, is made known in some way or

other to the whole hive. In order to ascertain this, he first divided

a hive by a grate which kept the two portions a few parts of an inch

separated from each other, so that the bees could not come at each

other, although any scent could easily have passed. In that part in

which there was no queen, the bees were soon in great agitation; and

as they did not discover where she was confined, in a short time they

began to construct royal cells, after which they grew more calm. Mr.

Huber next separated them by a partition through which they could pass

their antennæ, but not their heads. In this case, the bees all remained

tranquil, neither intermitting the care of the brood, nor abandoning

their other employments; nor did they begin any royal cell. The means

they adopted to assure themselves that their queen was safe, and to

communicate with her, was to pass their antennæ through the openings of

the grate, A most curious spectacle thus presented itself; an infinite

number of those organs might be seen at once, as it were inquiring in

all directions; and the queen was observed answering these anxious

inquiries of her dutiful subjects in the most marked manner; for she

was always fastened by her feet to the grate, crossing her antennæ with

those of the inquirers.

While we have been anxious to show that the function of feeling is not

the important and principal office of these singular organs, it would

be far from correct to state that the antennæ are not occasionally

employed, to use the popular term, as "feelers." All who have paid

any attention to the motions of insects must have seen the antennæ

actually employed as it were in exploring the number or nature of

objects immediately around. From these and the preceding remarks, it

becomes manifest, that, next to the organs of sight, the antennæ are

most important and useful appendages to the body of the insect. When

we consider the various purposes they serve, we become much perplexed

to understand how it is possible for one organ to fulfil such varied

duties; nor can it be explained. We are unable to conceive of the

senses of insects except by comparing them with our own; and in our

case there are no organs which can receive, and, at the same time,

communicate, intelligence. Our ears, eyes, nose, and the other organs

of the senses, have only one function severally assigned to them;

and had they more, there would probably be no little confusion in

our perceptions of external things. Such confusion does not probably

exist in the insect; but it is very possible that its perceptions are

somewhat different from ours.

Before we leave the region of the head, we have the important task

to fulfil, of describing the mouth of the insect: this part is more

complicated than the organs we have as yet seen, and requires,

therefore, a considerable degree of our careful attention to enable

us to do justice to it, and to carry in the mind a clear view of

this interesting portion of an insect's structure. "If," writes Mr.

Westwood, "a beetle, and a butterfly, a house-fly, or an aphis, be

examined whilst feeding, a totally different apparatus will be found in

each, although perfectly adapted for the mode of feeding. The beetle is

employed in gnawing and tearing in pieces hard or fleshy substances:

its instruments of manducation are, therefore, horny and robust. The

butterfly, on the contrary, has to seek its food at the bottom of the

tubes of flowers; and here in the glowing beams of the sun it revels

in its existence, and sips the most delicious nectar. It is necessary

for this purpose that it should be provided with a long and slender

instrument; but, from the very structure of this apparatus, it is

essential for its defence, that, so soon as the insect has ceased

feeding, the instrument should be lodged in a place of safety. It is,

therefore, rolled up in a beautiful spiral direction, and laid to

rest between a pair of hairy appendages, which will defend it from

injury. If we observe a common fly sipping up a drop of spilt wine, or

revelling upon a morsel of sugar, it will be found that its mouth is

totally unlike either of the former: it is short, thick, and fleshy,

and acts as a sucker, the nutriment ascending through the canal which

runs upward into the throat. The aphides and all their brethren have a

mouth differently constructed, being a long and slender pointed canal,

of a fleshy, or leathery substance, but furnished internally with

several slender bristles, which the insect employs as lancets to wound

its prey. In the flea, again, the structure is quite different."

[Illustration: _Proboscis of the Honey-Bee._]

[Illustration: _Proboscis of Carpenter-Bee_]

To the variations in the mouth of each of these insects it has been

thought good to attach a distinct name. When, for example, we speak of

a bee's _proboscis_,[V] we speak actually of its mouth. The mouth of

the butterfly is called by most entomologists _antlia_; that of the

aphis a _promuscis_; that of the flea a _rostrulum_. But the reader

must not allow himself to be confused by these terms; they all are but

names for modifications of the same part--the mouth. When the butterfly

plunges its long tube into the flower--when the fly intoxicates itself

with a drop of syrup, using its _proboscis_ to pump it up--and when the

flea thrusts its _rostrulum_ into our flesh, and quaffs our life-blood

as though it were nectar,--let us not forget the mouth is the organ

employed in each of these cases, varied and altered in form though it

certainly be.

[Illustration: Diagram of the mouth.--_a._ The _Labrum_, or upper lip;

_b._ The _Mandibles_, or upper jaws _c._ The _Maxillæ_, or lower jaws;

_d._ The _Labium_, or lower lip.]

In all cases, the various parts of the mouth may be reduced to six,

the names of which deserve remembering, and this will be rendered

easier by the accompanying diagram, in which they are all separated and

lettered, so as to distinguish each part; these six parts consist of

four side-pieces, and two other organs, one above, the other below. The

name of the upper organ is the _upper lip_, or in Latin, _labrum_; that

of the opposite lower one, is the _lower lip_, or _labium_. The upper

pair, of side-pieces, are called the _mandibles_, or upper jaws; the

pair below are the lower jaws, or _maxillæ_.

Let us now briefly mention the use of these various parts of the

insect's mouth; beginning with the upper lip, (_a_) or _labrum_. Unlike

that organ in ourselves, the insect's upper lip is generally, in such

insects as bite their food, a plate of horny substance, which serves

the purpose of an upper covering to the rest of the mouth. Like our own

upper lips, however, that is to say, like those of men, at least, it is

fringed with a sort of _moustache_ in most cases.

The _mandibles_, (_b_) or upper jaws, in the biting insects, are

instruments for cutting the food in pieces. When we bite our food,

the movement of our jaw is upwards and downwards; but in the insect

it is like that of a pair of scissors, or from side to side! These

jaws are sometimes frightful-looking instruments, resembling, in the

stag-beetle, _horns_; and their power is proportionally great. Although

their general use is to masticate or crush the food for the insect,

this apparatus is often employed as a formidable weapon of defence, or

offence; and very frequently in the excavation of a nest or retreat for

the insect. They are sometimes so constructed, as to look as if they

were furnished with several teeth.

[Illustration: _The Stag-Beetle, representing its enlarged Mandibles,

like horns._]

The _maxillæ_, or _lower jaws_, are less firm and strong than the

preceding; but they are more complicated in their structure, and have

attached to their sides remarkably delicate little processes like the

antennæ, which are called the _palpi_, or, less properly, _feelers_.

The lower jaws are much varied in structure in different insects; as

may well be imagined, when it is mentioned that the long and beautiful

spiral tube of the butterfly, by which it drains the juices of the

flower, is, in reality, composed of the maxillæ, or lower jaws. In

ordinary cases, the principal use of the lower jaws appears to be to

hold the food, while the upper jaws bruise and crush it; but their use,

of course, varies with their structure and modifications.

The last part of the mouth is the _labium_, or lower lip. This also is

a very complicated organ, generally serving to close the mouth from

beneath, like the upper from above. It boasts, like the same organ

in higher animals, of a _chin_ below it, called the _mentum_, and on

each side of it are a pair of feelers, or _palpi_, like those of the

maxillæ. In the centre a little tongue-like projection is visible in

the figure, which is sometimes called the _tongue_, but perhaps not

correctly, if by that term is meant the apparatus for _tasting_. The

lower lip is as much varied as the maxillæ.

It would be impossible, without going too far into minute technical

details, to explain to the reader how all these various parts of the

mouth are so modified, and altered, as to assume the very different

appearances presented to us in the insects already mentioned. This

pleasure must be reserved for the time when, well acquainted with the

generalities of insect history, which alone form the scope and subject

of this little work, he feels anxious to study entomology as a science;

and he will find a number of excellent books which will then well repay

his attentive perusal, and satisfactorily answer all his inquiries on

this and other difficult topics connected with this science.

It cannot fail to be noticed, that in this description of the insect's

mouth no mention has been made of its organs of _taste_. Its eye, and

probably ears, and means of touch, have all come before us; but where,

it will be asked, is its tongue? The little organ mentioned as a part

of the insect's lower lip, although strikingly resembling a tongue in

some instances, is in others very different from it, and appears in

such cases to be quite unfitted to act as the organ of taste. We must,

therefore, suppose, that other parts of the lower lip or mouth have the

same faculty in addition to the so-called tongue. It is very certain

that insects have the faculty of tasting, and also of discriminating

between their food; as few will be disposed to question, who will

place a plate of salt, and a plate filled with moist sugar, in a

sunny window on a fine day; it will soon become evident which will be

favoured with the attention of the flies.

Neither has any mention been made of a _nose_.[W] A common flesh-fly,

however, will soon satisfy us, that it is not devoid of some organ or

other which answers this purpose. If we cover a piece of meat under

a cloth, or put it into a wire safe where it is certain that the fly

cannot see it, it will scent it out as readily, or even more so, than a

cat or a dog would. Sometimes this insect's nose proves a treacherous

guide, for a plant has been described, called the _carrion-flower_,

which diffuses an odour like that of putrid meat, which attracts the

fly, and induces it to deposit its eggs thereon, under the idea that

its future young will thus be hatched upon a certain source of food;

but in vain, for they perish almost as soon as born, finding nothing

in the plant whereon to exist.[X] But as to the precise seat of the

organ of this sense, opinions are greatly at variance. Some believe it

to exist in the _spiracles_, some in the mouth, and some in a special

organ which they call the nose, but which does not seem in reality to

fulfil that office, at any rate, in the generality of cases. M. Huber

showed the existence of this faculty to lie somewhere about the mouth,

by some interesting experiments upon bees. He presented successively

to all parts of a bee's body a camel-hair pencil dipped in oil of

turpentine, to which most insects are extremely averse, but the bee

took no notice of it. He then took a very fine hair pencil, while

the bee had extended its proboscis, and presented it to its eyes and

antennæ without effect; but when he pointed it near the cavity of the

mouth, above the insertion of the proboscis, the creature started back

in an instant, quitted its food, clapped its wings, and walked about

in great agitation, and would have taken flight if the pencil had not

been removed. On this it began to eat again; but on the experiment

being repeated, it showed signs of similar discomposure; oil of

marjoram produced the same effect, and more promptly and entirely. He

then seized several bees, forced them to unfold their proboscises,

and stopped their mouths with paste. When this was sufficiently dry to

prevent their getting rid of it, he restored them to their liberty;

they appeared by no means incommoded at being thus gagged, but moved

about and breathed as readily as their companions. Huber then tempted

them with honey, and presented to them, near the mouth, oil of

turpentine and other odours that they usually have an aversion to; but

all produced no sensible effect upon them, and they even walked upon

pencils saturated with them!

Leaving now the head of the insect, it is necessary for us to make

some mention of the parts attached to the _thorax_, or trunk. In the

head division we have seen that the various organs of the senses are

situated: we shall now find that in the thorax division are placed the

organs by which the insect is either wafted in rapid evolutions to the

highest air, or runs with incredible rapidity along the surface of

the earth. We have already described, on a previous page, the general

structure of an insect's wing. It remains, therefore, for us here to

advert to a few other facts in connexion with these elegant appendages.

[Illustration: _The House Fly. Natural size and magnified._]

[Illustration: _Scales of Insects Wings magnified._]

The natural number of wings in the insect world is four, arranged in

two pairs. But this number is obscured by the modifications to which

in many instances one or other of the pairs becomes subject; and we

should, if this were not remembered, become somewhat confused at taking

up the first insect that came in our way, which would probably be the

common fly, and finding that we could only recognise two large wings

instead of four. In this tribe of insects the hinder pair of wings

is reduced to a pair of slender knobbed filaments. Some insects are

without wings at all. The ant, the bee, the dragon-fly, the house-fly,

and many other insects, are furnished with wings of gauze-like

transparency and structure, often crossed in a curious manner by the

_nervures_, of which we before had occasion to speak. These wings are

called _membranaceous_. In the moth and butterfly tribes the wings

are covered with what appears to be a delicate, beautiful powder, but

is in reality a multitude of exquisite scales, of the singular forms

represented. The engraving shows the shape of the scales on the wings

of these insects; on examination with a good lens, it appears that the

long and hair-like scales are planted at the margin of the wings, and

contribute to give to the edges that beautiful feathery look which is

so much admired, while the short scales were placed principally on

the middle portion of the wings; their numbers are almost infinite.

If a butterfly is allowed to flutter awhile in a box it will cover

every portion of its surface with them, and yet, on being permitted to

fly out, we may scarcely perceive that it has lost any of its fairy

plumes. Whether Leuwenhoek actually took the trouble to count so many,

or arrived at the result from calculation after counting those on a

given space, we do not know, but he declares that he found more than

four hundred thousand on the wings of the silk-worm moth; and in those

of larger moths and butterflies the number must greatly exceed this.

They are generally arranged like the tiles on a house-roof; and if

they are scraped off, the minute dots where each was attached becomes

distinctly visible. The term used to indicate the tribe of insects

to which the moth and butterfly appertain, is, as has been before

remarked, _Lepidoptera_, or "scale-winged," from this very fact. Some

membranaceous wings are clothed with fine hairs.

[Illustration: _Blight-Beetle. Natural size and magnified._]

If we take up a beetle, and look for its wings, for the first time,

we shall probably fail in detecting them, that is, of course, if the

insect has not been observed in the act of flying. On examining the

body we see, indeed, a pair of shining horny plates on its back; but

surely these are not wings? Presently, the insect having mounted to

the top of our finger, prepares for flight; its two hard cases fly up,

and, behold! from beneath them appears a pair of the most beautiful

gauze-like wings, which it quickly unfolds, puts into motion, and

then flies away. The two thick and horny covers for these delicate

organs are called _elytra_, or "wing-cases." They are really the

first pair of wings, much thickened; and their use is to protect the

delicate membranous wings of the hinder pair, beneath them. When the

insect flies, they open like a box-lid, and are carried out of the way

of the other wings; when the insect rests it carefully folds up its

other wings, and then these close over them, and preserve them from

all injury. As the insects in which they are found frequent places of

danger, burrow underground, or take up their abode under stones, it is

manifest how admirable a contrivance this is for such purposes, and

how efficiently the fragile wings will be covered and protected by

such shields. The first pair of wings is sometimes thickened to the

consistence of parchment as a cover to the other wings; and they are

then called _tegmina_, or "wing-covers."

There are two other circumstances in connexion with this part of our

subject, which deserve noticing. If the reader will take into his

hand a large blow-fly, and carefully examine its body with a lens

near the spot where the wings are connected to it, he will succeed in

discovering two organs of a curious kind. One of these, is a small

membranous piece connected with the trunk-end of the wings, and is

generally called the _winglet_, or _alula_. The other looks like

a little drumstick hanging down, and is called the _balancer_, or

_poiser_, or in Latin, the _halter_, or bridle. It is not clear of

what use either of these organs is. Since the winglets are the largest

in the heaviest bodies, and are altogether wanting in the lightest,

it appears probable that one of their principal uses is to assist the

wings during flight. If one might hazard the conjecture, perhaps they

act like the _parachute_ of a balloon. As to the so-called _balancers_,

it has been considered that they serve to poise the insect while

flying. Dr. Derham considered that they kept the body steady during

flight; and he states that if either a poiser or a winglet is cut off,

it will fly awkwardly and unsteadily, as if it had lost some very

necessary part. Another observer states, that he cut off the winglets

of a fly, leaving both its wings and poisers; but it could no longer

fly. He also cut off, in another fly, the poisers alone, and the same

result took place. On cutting off both the poisers of a crane-fly, he

says it was unable either to fly or walk.[Y] Mr. Westwood says he has

seen the poisers beat rapidly upon the winglets like drumsticks on a

drum, and it has been supposed that this action is the cause of the

_hum_ made by the insect in flying. This is doubtful, because it has

been found that after the winglets are cut away the humming sound is

still produced; and some humming insects have no winglets.

[Illustration]

So much importance did Linnæus, the great father of natural history,

attach to the character of the wings in insects, that he arranged

the various families of insects under several heads expressive of

the leading character of their wings. The orders into which he thus

divided insects are seven in number: 1. _Coleoptera_, or case-winged;

2. _Hemiptera_, or half-winged; 3. _Lepidoptera_, or scale-winged; 4.

_Neuroptera_, or nerve-winged; 5. _Hymenoptera_, or membrane-winged; 6.

_Diptera_, two-winged; and, 7. _Aptera_, or wingless: the Greek word

_pteron_, signifying "a wing," furnishes the termination to each of

these titles; the prefix is also derived from the Greek, and its import

may be derived from the translation attached to each. This system has

been extended by modern entomologists, who have subdivided the 2d, 5th,

and 7th orders into additional ones.

In the opposite cut the insects represented illustrate each of the

Linnæan orders. They are--1. a Beetle; 2. an Aphis; 3. a Butterfly; 4.

a Bee; 5. a Dragon-fly; 6. a House-fly; and, 7. a Spider.

As these organs exhibit to us in the most conspicuous manner the

exquisite beauties wherewith it has pleased God, the Almighty Creator,

to adorn the insect world, we may be allowed to make some reference

to the colours of the wings, before proceeding to speak of those

organs by which the insect moves on earth. Some, of the beetle tribe,

are like tiny masses of burnished metal gleaming with colours of the

most exquisite description. A vast number of locusts are remarkable

for the splendour of their wings. Many dragon-flies are adorned with

wings vying with those of the butterfly in loveliness. The wings of

many flies are exquisitely painted with the most brilliant metallic

hues, green and gold; and even those of a house-fly are often very

beautiful by their having the property of _iridescence_, or reflecting

the prismatic colours of light. But insects of every tribe, however

splendid in attire, fade before the glories of the butterfly tribe.

Linnæus, speaking of the splendid colours of these insects, and

particularly of the gorgeous tints which appear on the upper surface

of the wings of a butterfly called the Morpho Menelaus, and another,

justly observes, that there is scarcely anything in nature that for

brightness and splendour can be paralleled with this colour. It is

a kind of rich ultramarine, that vies with the deepest and purest

azure of the sky; and what must cause a striking contrast in flight,

the prone surface of the wings is as dull and dark as the opposite

is brilliant; so that one can conceive this insect to appear like a

planet in full radiance, and under eclipse, as its wings open and

shut in the blaze of a tropical sun. The scales on the wings of some

species shine with such extraordinary intenseness and brilliancy,

that it is impossible to look at them in a bright light, as they

completely dazzle the beholder. Messrs. Kirby and Spence say, they

"know no insect upon which the sight rests with such untired pleasure

as upon the lovely butterfly that bears the name of the unhappy Trojan

king (_Papilio Priamus_); the contrast of the rich green and black

of the velvet of its wings with each other, and with the black of its

abdomen, is, beyond expression, regal and magnificent." What adds to

the beauty of the wings of this tribe of insects is the appearance

of the beautiful spots like eyes, which are so familiar to us, and

which are almost without a parallel, except in the animal world. This

ornament gives to the wings of a butterfly an indescribable life and

beauty, and constrains us as we contemplate it to acknowledge that

'Solomon, in all his glory, was not arrayed like one of these.' The

astonishing variety of combination in the colours communicates an

inexpressible charm to these insect glories: here is a lustrous blue,

a glowing orange, a delicate lemon, an exquisite pink, a fiery copper,

or a spotless white. None but a Divine hand could have produced such

effects as are exhibited in these most gorgeously painted organs. No

work of man will endure comparison with them. The most elaborately

finished miniature upon which the artist may, in the features and

dress of the person, have expended all the resources of his art in the

production of harmonious and pleasing tones of colour, appears but as

a muddy, lustreless patch, when placed side by side with one of the

butterfly-beauties of the tropics, or even of our own green fields.

[Illustration: _Hind Leg of a Bee._]

We must not, however, allow the fascination of these beautiful objects

to engross our whole attention; and it is now time for us to state some

particulars connected with the _legs_ of the imago, or perfect insect.

Six is the true number of legs which belong to the insect in the imago

state. They are connected to its body at the thorax, and are formed of

a series of minute tubes, provided internally with muscles and nerves.

They are commonly divided into four parts; _a_ the haunch, _b_ the

thigh, _c_ the _tibia_, and _d e_ the foot.

The front pair of legs, or, as they are generally called, the

_forelegs_, are considered by some authors to be really the insect's

_arms_, the last portion of them being the _hand_. Certainly they are

often as useful to the insect as is this admirable organ to ourselves;

not only are they serviceable in walking, but they also enable the

insect to climb, to lay hold of various objects, or to catch their

prey, to dig in the earth, and in many instances to clean the head

and face of the creature; an operation in which many of them, and

particularly flies and bees among our domestic insects, are most

praiseworthily particular; having apparently an aversion to nothing so

much as to a _dirty face and unbrushed jacket_! The other pairs of legs

are altered in various manners in order to fit them for the different

purposes for which they are required by the insect.

[Illustration]

The purposes for which the legs are put into requisition are, as will

be easily guessed, for walking or running, for jumping, for climbing,

and for swimming. Most surprising in all these respects is the degree

of agility and swiftness with which it has pleased the Divine Creator

to endow these insect-organs. M. Delisle once observed a fly, only

as large as a grain of sand, which ran three inches in half a second,

and in that space made the enormous number of _five hundred and forty

steps_. If a man were to be able to walk as fast in proportion to

his size, supposing his step to measure two feet, he would, in the

course of a minute, have run upwards of _twenty miles_, a task far

surpassing our express railroad engines, or the famous Seven League

Boots recorded in the nursery fable. In leaping, also, insects far

excel man, or any other animal whatever. The flea can leap two hundred

times its own length; so also can the locust. If a man were six feet

long, and could leap as high and as far as one of these insects, he

might stand near Bow Church in Cheapside, leap up into the air over

the top of St. Paul's cross and alight at the bottom of Ludgate Hill;

which would be something more wonderful than it has ever entered into

the minds of the writers of fairy tales to conceive of. The insect

called the frog-hopper can leap more than two hundred and fifty times

its own length. Some spiders can leap a couple of feet upon their prey.

The legs of insects that swim are generally peculiarly fitted for it,

either by their being expanded somewhat like an oar, or by having a

dense fringe of hairs upon them. The water-beetles, after rising to the

surface of the stream for a supply of fresh air, dive down to their

watery home again, taking a clear silvery bubble along with them; and,

in this action, they move with considerable rapidity their swimming

legs, which are clothed with hairs. The water boatman swims _upon his

back_ by means of his singularly formed legs. The little whirl-gig,

of which we have before spoken, swims by means of its legs, which are

paddle-shaped. By means, it may be, of some peculiar secretion, which

repels the water, some insects can actually walk upon its surface, and

that as readily or more so than upon land. Those who know the pleasures

of shooting with polished skates over clear ice, when it almost seems

as if we were moving in the air, and no more condemned to earth, can

imagine something of the delight these insects must experience, who

can glide as swift as thought over the glassy surface of the brook.

Sometimes the shape of the hind-legs is remarkably altered, and,

perhaps, the most extraordinary instance of this in the whole insect

world is, the foreign insect, which has been called the _Kangaroo_

beetle. The cut represents faithfully this most wonderful creature; and

we could almost fancy, as we looked at it, that by some accident the

front pair of legs and the head had been twisted round, leaving the

hind legs and part of the body turned in the opposite direction. It

need scarcely be added, that the origin of this insect's curious title

was derived from the resemblance borne by its hind legs to those of the

animal whose name it bears. In some insects the legs fold upon each

other, and are packed into a very small compass: this is particularly

the case in a species of wood-louse, which roll themselves up into

balls precisely resembling beads or pills, as may be imagined from

the following anecdote. A servant maid of the great Swammerdam, while

walking in the garden one day, found a large number of round, black,

shining beads, which were streaked with white bands, and presented a

very pretty and attractive appearance. Gathering a number of these in

her hand, she thought she would convert them into a necklace, or, for

ought we know, into a rosary, when, to her great surprise, the beads

became animated as soon as ever they felt the point of the needle, with

which she was about to thread them, and began to struggle actively to

get away; not, however, too quickly for her; for with a violent scream,

imagining the beads were bewitched, she ran into the house. Some of the

beetle tribe thus fold up their legs, and roll themselves up so as to

resemble little globular pebbles.

[Illustration: _Kangaroo Beetle._]

_The Abdomen_ is, then, the only remaining portion of the insect which

we have now to notice. It has no legs attached to it, and contains the

intestines, and other portions of the insect's internal anatomy. It is

formed of a varying number of rings, which are easily distinguishable

in the wasp and many other insects, and these rings are connected

together by delicate folds of membrane, fitting sometimes into each

other like the tubes of a telescope; in other instances fastened

together, like so many hoops, by their edges. In consequence of this

mode of structure it is often very movable, and may even be bent into

a half curve, in various directions, at the pleasure of the insect.

The common earwig is particularly gifted with this movableness of its

abdomen; and so are many insects which carry weapons of offence or

defence in their tails. These organs, or appendages, are deserving of

a brief notice, although it is probable that the structure of some of

them is already familiar to most readers.

[Illustration: _A Bee's Sting magnified._ _a_, represents the pair of

darts; _d_, a single dart; _b_, the poison-bag; and _c_, the sheath.]

The sting of the bee is, perhaps, as formidable a weapon as any of

those attached to the abdomen in insects; under the microscope the

structure of this apparatus appears in all its beauty. It is found to

consist of a sort of sheath, or scabbard, which is composed of two

pieces, and is of extreme fineness, as will be readily made visible

by placing a fine sewing needle by its side, when the latter will

more resemble a bar of iron from the smith's forge, or a kitchen

poker, than anything else; while the former will, under the strongest

magnifying power, exhibit a smoothness, elegance, and polish, of the

most beautiful description. When the bee thrusts forth its sting, it is

the sheath which we generally see, and not the more delicate apparatus

which is enclosed within it. Inside this scabbard is a pair of most

fine darts, which are even more delicate than the human hair, and

are therefore invisible to the eye, unassisted by a good lens. These

darts are notched like very fine saws at the end, the teeth being so

directed as to oppose the retraction of the instrument if it is thrust

into the human skin; the sting being therefore left in the wound, and

the wounded person having the comfort of knowing--if we should call it

a comfort--that the insect will surely die speedily, in consequence

of its attack upon him. An exquisite adaptation of fine muscles is

attached to this weapon, by which it is forcibly driven home. The

venom which produces the pain and inflammation is contained in a small

muscular bag in connexion with the sting; and when the latter is thrust

out, the poison is also forced out and flows into the wound. The sting

of the scorpion is a less complicated, but more dangerous weapon,

though not often fatal. The earwig, though unprovided with a sting,

carries a most awful-looking forceps in its tail, which it can put in

action with great force on occasion of danger; and since it can twist

its abdomen about with great facility, it is a contrivance of which a

tender finger may well be afraid.

Among the wingless insects of Linnæus, is one which he has called

by a name which signifies that it has _got a leg in its tail_; and

this is actually the fact, in so far as that these insects have an

organ in their tail, which answers all the purpose of a leg. Some of

these little creatures, which are black, may be often found in spring

strewed in infinite numbers upon the surface of the water in ditches

or pools; and may be seen jumping about on the surface of the water as

if bewitched. At their tail is a fork-like organ, which is generally

bent under the body; but when they spring up they do so by quickly

unbending this fork, the resistance it meets with being sufficient to

carry it to a certain distance. Another insect is provided with eight

pair of springs in its abdomen; by means of which it can leap to a

great distance with most astonishing agility. Here we shall conclude

the external anatomy of the insect, in the imago state.

CHAPTER III.

RESPIRATION OF THE IMAGO.

Perfect insects breathe. That this is so, the following experiments[Z]

will satisfactorily prove. A spider and a fly were put into a glass

jar, the mouth of which was closed all but a hole by which a tube was

admitted. The tube was then connected with a pipe by which a supply of

common coal-gas was poured into the jar, and when it was considered

to be full of gas, and that all the air had been displaced, the tube

was closed, and the insects were left shut up in an atmosphere of gas.

In a few seconds both became very uneasy, the fly more particularly

so; and in a few seconds more the fly began to agitate itself, to

buzz against the sides of the glass, and to tumble over in the most

extraordinary manner; the spider ran hurriedly about, as if astonished,

and not knowing what to make of his new position; but presently he

became very quiet, and, turning on his back, looked as if dead. For a

minute or two the fly, which was a large, active, flesh-fly, continued

its noisy evolutions, dashing itself, as if intoxicated, on every side

of its transparent prison. At length, as if exhausted, it lay on its

back, its limbs paralyzed, but the wings still moving with extreme

rapidity, and causing it to spin round in the most singular manner.

Ultimately it, too, became perfectly without motion. After the lapse

of about ten minutes, fresh air was gradually let into the jar, and it

became most amusing to watch the return of both these insects, which

had previously been as it were in the very jaws of death, back to life

again; twitchings of their limbs, and slight convulsive movements,

were the first indications of returning activity; and in a few minutes

more both insects, now placed in a perfectly pure atmosphere, were as

lively as before the experiment, and were allowed to make their escape

into the open air. With other insects the same effects were produced

by saturating a piece of blotting paper with ether, and dropping it

into the jar, which was immediately covered over. In several other

experiments the newly-discovered powerful fluid _chloroform_, by means

of which the operations of surgery are performed without pain, was

employed; and it was remarkable to notice how quickly the insects were

overpowered with the vapour of this potent liquid. In no instance was

death produced by the gases or vapours employed. Wishing to destroy

without pain a beautiful specimen of a goat-moth, it was first

stupified with the gas, then transfixed with a pin, and again plunged

in an atmosphere of gas all night long; but alas! for the unhappy

insect, the morning dawned, and it was yet alive.

In these simple experiments, which were repeated sufficiently often

to render the results certain, we have a most interesting proof that

insects breathe. The first struggles and apparent intoxication can

be compared to nothing more exactly than to the same phenomena when

they take place in human beings breathing the vapours of ether, or

chloroform. The subsequent state of insensibility was precisely

similar to that induced in persons who are put under the influence

of these vapours. An amusing instance of the restorative powers of

fresh air occurred in the course of these experiments. A blue-bottle,

which was purposely selected of as large a species as could be found,

was first intoxicated and rendered insensible by coal gas, and was

then as quickly as possible put into a net of the geometric spider:

instantly the spider flew upon his bulky captive, but the fresh air

began to take effect on the fly, and it commenced struggling in the

most furious manner. Although the spider cast out a cloud of web, and

in the most energetic manner endeavoured to envelope its prey, the fly

seemed likely to be the victor; one of its large and powerful wings got

free and flapped violently until the meshes of the web gave way, or

was, perhaps, broken by the weight of the insect, and fly and spider,

being suspended in the air, spun round so swiftly as to be quite

indistinguishable. Ultimately, the spider conquered; and, suspending

the huge body of its victim by a rope in the air, returned for a short

time to its den.

If insects do not breathe, then all these results are quite

unintelligible; for it would be immaterial to the insect what

atmosphere it might happen to be placed in. A number of illustrious

authors have recorded the result of their experiments upon the effects

of other gases on insects. Bees, and other insects, have been placed

under the exhausted receiver of an air-pump, and death ensued in a

short space of time. It has also been found, that when the bodies

of insects are covered with oil or grease, so as to stop up their

breathing pores, they soon expire. It has been proved by carefully

conducted experiments performed by Mr. Ellis, M. Sorg, and other

observers, that on placing flies in a measured quantity of atmospheric

air, at the end of a day or two almost the whole amount of the oxygen

of the air had disappeared, and the same amount of carbonic acid

had appeared in the chamber in which the insects were confined. We

need not, however, after all that has been said on the subject of

the respiration of insects in their various stages, enter into any

further proofs that insects breathe not less perfectly in their imago

condition than in any of the preceding states; in fact, they perform

this function far more prominently in this their last state than in

any of the foregoing. It will also be unnecessary to enter into a

consideration of the minute particulars connected with this subject, as

several of these have been previously glanced at.[AA]

The air enters the body of the insect at the spiracles, or

breathing-pores, which are arranged along the abdomen, and situated

at the side of the wings, and is received by a large tube on each side

of the body, running its whole length, or nearly so, as we before

mentioned. This tube, and those which it gives off as branches, are

called _tracheæ_, or air-pipes. The tracheæ are formed in the most

wonderful manner, so as to keep them always open, that the air can

readily pass through them. Perhaps some of our readers have seen the

contrivance adopted by sailors in order to blow air down into the hold

and cabins of the ship; for those who have not, we may take the liberty

of mentioning, that it is a large tube made of canvass, open at the

side near the top, so as to catch the wind, while the bottom of it

opens into the cabin. Now, the sailors always place the mouth of this

tube towards the wind, which is forced down the tube into the cabin

either by its own speed, or by that of the vessel, in the case of a

steamer, and so fills the cabin below continually with fresh air. But,

it will be asked, how do they contrive so to keep the sides of the bag

from flapping together as to prevent them from closing? By imitating

a contrivance which exists in the trachea or air-tube of the insect;

they place at certain distances inside this canvass tube a series of

wooden hoops, which entirely prevent its collapsing, as it otherwise

would do. The most minute air-tubes of an insect are furnished, not,

indeed, with a series of rings, but with what serves the same purpose,

a firm but delicate coil of cartilage like a spiral spring, over which

the membranous lining of the tube is stretched. Thus these tubes remain

constantly open; and, whatever may be the movements of the insect, they

retain this position. The tracheæ branch out in a most wonderful manner

inside the insect's body: as thickly as in our bodies and in those

of animals the fine blood-vessels divide until they form a mesh so

close that we cannot prick ourselves with a pin without piercing some

little tubes, and drawing blood; so in those of the insect, the minute

air-pipes run in every direction, and divide into countless thousands

of branches, which only become visible under the highest powers of a

good microscope. The large tubes are seen without difficulty in many

insects; and a drawing, which may give some idea of the immense mass of

air-tubes existing in the body of an insect, is annexed: all the rest

of the body is supposed to be cut away, and the larger tubes only are

shown, as it is impossible to represent the smaller ones so as to give

a clear view of their arrangement; they would cover the drawing like a

cloud of the finest and most delicate lace-work. In short, in insects,

there being no separate lungs in a particular place, as in the animal

frame, the air is necessarily carried all over the body, so as to be

supplied even to the most minute parts; thus the lungs may be said to

extend through the whole body.

[Illustration: _The Air-tubes magnified._]

[Illustration: _The circulation in an Ephemera. The arrows represent

the direction of the blood-current._]

As the reader has laid his finger on his pulse, or felt his heart

beating within him, or seen a drop of blood ooze from his wounded hand,

have the questions never occurred to him,--Have insects blood-vessels,

and a beating heart? And if so, have they blood like ours? Many a

wise man of old, even the great Baron Cuvier himself, has supposed

that there was no circulation of the blood in insects. But, with

a magnifying glass and a caterpillar before us, we shall soon be

satisfied that this is a great mistake, for by carefully looking

along the insect's back we shall perceive in that part a very evident

pulsation, as though a fluid were pushed at regular intervals towards

the head. The cut represents the circulation in the vessels of the

larva of an Ephemera. But insects have no heart, like that of man

and animals. What, then, can this beating organ be which we behold?

Although it is not like our heart, it is nevertheless an organ which

serves all the purpose of ours, and pumps on the blood with great

regularity. Instead of being a muscular organ of small size, but great

thickness, like our heart, it is in reality a long tube, called the

_dorsal-vessel_, running along the abdomen and thorax of the insect,

into which the blood is poured by the veins, and out of which it is

forced on towards the head by the regular contractions of its side.

This causes the beating movement which we saw in the caterpillar.

Perhaps there may be some curiosity to know whether an _insect's pulse_

beats faster or slower than ours. John Hunter counted thirty-four beats

in a minute in a silk-worm. Another observer counted thirty a minute

in a caterpillar of the pine-moth. But in the imago state the pulse

appears to move much quicker: and it is easy to make an insect's beat

extremely fast, by exciting or provoking it. Mr. Newport having done

so to a bee, counted as many as 142 beats a minute. In a middle-aged

man the pulse beats about seventy times in a minute; in a child seven

years old about eighty-five times; and at the age of fourteen about

eighty times. Hence it follows that our pulse beats about twice as

fast as that of an insect in the larva state: in the imago state it is

probably, as a general rule, at least in winged, active insects, higher

than ours.

CHAPTER IV.

FOOD AND DEATH OF THE IMAGO.

But we have something to say about the food of insects. Although it

has been already laid down as a general rule, that insects in their

perfect state, do not eat in any degree with the voracity they exhibit

in the larva form, it is nevertheless true that they do both require

and devour food in considerable quantities, and of various kinds. Some,

for example, are exclusively _vegetable_ feeders. They attack all the

parts of plants, not excepting even the root and the bark. Some, with

an elegant taste, select the yellow pollen of flowers for their dainty

and delicate food. And others, more refined still in their appetites,

will have nothing but the fresh distilled honey that lies hid at the

bottom of the flowers, pumping it up by the beautiful spirally-coiled

tube which forms a part of their mouth. Need we say these are the

butterflies? The fly loves a grain of sugar, or a savoury joint of

meat: and to other insects, to use a quotation of Mr. Spence's, which

prefer the paper of our Atlases, or maps,--

----"a river and a sea

Are a dish of tea,

And a kingdom bread and butter."

A large number also are _carnivorous_ creatures: need we mention the

spider-tribe? a name of terror to myriads of our summer insect-friends.

The beautiful _cicindelæ_, called by Linnæus the "tigers to insects,"

prey upon the whole insect race, and are endowed with powers of offence

and destruction, to a degree sufficient fully to justify this title. In

France, we are told, the butchers are very glad to have wasps attend

their stalls; since they drive away, and undoubtedly prey upon, the

numerous flies which frequent these places. The larger species of ants

are equally ferocious, attacking any small soft-bodied insect they may

meet with, and when killed dragging it to their nest. The beautiful

lady-birds, which we look upon with so much tenderness, remembering the

ditty,

"Lady-bird, lady-bird, fly away home,

Your house is on fire, your children will burn;"

are in the larva state furious destroyers of other insects, and will

gobble up aphides by the score in a very short time. The dragon-fly

too stands conspicuous among the insect devourers, not only in its

larva but in its perfect condition, and falls upon multitudes of

insects, plucking off their wings, and with savage relish devouring

their bodies. We are not, however, to suppose that the appetites of

carnivorous insects are confined to insect-food. The blow fly lives

upon and defiles by depositing its eggs in our butcher's meat. The

cockroach will polish a bone as clean as, or cleaner than, any dog

will, and, indeed, will consume almost anything that happens to come

in its way. Lastly, we may not omit to mention, that some insects have

to plunge their armed mouths into our flesh and that of other animals,

and to slake their raging thirst in a draught of our life-blood: among

which we will only enumerate the musquito, the gnat, and the flea. We

need scarcely say, that insects are provided with proper organs of

digestion.

Singular to add, some insects in the perfect state do not eat at

all. The silk-worm moth, and the _Ephemeræ_, are amongst this number;

they live so short a time, as not to require food. Some insects also

possess a most extraordinary power of abstaining from food. There

have been at different times wonderful tales related of human beings,

who, in a supposed trance, have endured the privation of food for an

extremely long time,--weeks, and even months. And more recently we

have an account of an Indian who suffered himself to be buried alive,

built over with bricks and mortar, and a great seal set upon the only

opening to his tomb, a guard being also set; and, after the expiration

of a certain time, before agreed upon, the sepulchre was opened, and

he was taken out--alive! All this is extremely wonderful, if we could

only feel certain that there was no deception in the case. But it is

nothing to what can be adduced from the insect world. The ant-lion has

been known to endure a fast of _six entire months_, and to be as lively

as possible at their termination. An author quoted by Messrs. Kirby and

Spence kept a spider in a sealed glass for _ten months_, at the end of

which time, though shrunk in size, it was as vigorous as ever. And Mr.

Baker relates that he once kept a beetle alive for three years without

food of any kind whatever!

When we call to memory the intense voracity of the insect while a

larva,--how insatiable its appetite, how extensive its ravages,--and

contrast it with the perfect insect, we are struck with astonishment.

Why is this, we ask, that in all cases insects eat less when they are

fully developed, than when in their infancy and youth? It is as if a

full-grown healthy man were to eat less than his little child a year or

two old. The reason appears to be, that in the imago state no further

changes (which consume a great deal of material, as may be imagined

when we remember the loss of substance in every cast of the skin) are

necessary; the insect only requires food sufficient to preserve its

life and activity in the state to which it has come, and needs no

laying up of stores of fat for future consumption. Fluttering awhile in

glorious apparel, through a world of flowers and sunshine, the period

of its life runs out, and its only further change is--to die, and

return to its kindred dust.

But, before this takes place, one last duty devolves upon the insect,

which, unfulfilled, would leave the world at its death with one link in

the chain of creation broken off,--this is, to make provision for the

continuance of its species. We have already said, that insects, as a

general rule, have been, no doubt in wisdom, destined to deposit their

eggs not knowing what is to come forth of them, and never enjoying that

happiness which is granted to many other beings,--the happiness of

parental love. Some most interesting exceptions to this rule will have

also been mentioned, in which a mother's love for her young has been

exemplified in a remarkable manner.

Yet, though denied this pleasure and privilege, the mother-insect

exercises, as we have before seen, all the care and forethought of the

most affectionate parent, in depositing its eggs, and in making such

arrangements as will be most conducive to the happiness and well-being

of its future progeny. We can scarcely say that in this it shows that

it possesses anything like such a feeling as that of a parent towards

its child. It takes the wonderful precautions, and performs the

singular actions, which have been already in part recorded in our first

chapter, in all probability without being aware of the reasons why it

should do so. How can it tell that its future progeny will eat this

food, or that food? How can the poor blow-fly, when it leaves its eggs

on our food, be certain that it is appointing a suitable place for the

birth-spot of its progeny? Why does it not select the green surface of

the leaf, or the warm corner of the window, or the bare earth, for this

purpose? We might say, perhaps, in this instance, that the insect is

only choosing the place where it obtains its own food. But what shall

we say when we find insects, such as the butterfly, depositing their

eggs upon plants which they never frequent at any other time, and from

which they never obtained a particle of food themselves? Some, for

instance, deposit them on the nettle, although never tasting anything

from this plant themselves, while the young which are to proceed forth

from the eggs feed voraciously upon it.

We cannot, in any way but one, account for this forethought. The

poor insect, left to itself, would undoubtedly deposit its eggs

indifferently anywhere; and the result would be, that its young family,

if hatched at all, would awake only to find themselves in a desert,

without food, or hope of reaching any, and would soon perish. Need we

say how it can be easily accounted for? Surely, only, because it is

God who has instructed these humble creatures, enduing them, if not

actually with the powers of foresight, at any rate with the instinct

which impels them to proceed in such a manner as if they were thus

endowed. By a most wonderful exercise of wisdom He has taught them to

distinguish even between the different species of plants; and rarely,

indeed, do we find that the insect commits a mistake, or selects a

wrong or fatal birthplace for its young.

Insect history is full of such instances of the great Creators wisdom

and love. Although they are not rendered conspicuous to every eye, they

are not the less real, nor the less amazing. In our Life of an Insect,

many have been the occasions when we have stopped to wonder afresh at

continually new and more striking indications of His adorable goodness

and power, as the different phenomena of insect-life have been paraded

before us. Yet this is but a very minute portion of what really exists

of the admirable and beautiful in the insect world. Not one volume,

not a hundred volumes, would suffice to relate the interesting facts

which connect themselves in various ways with the insect's life. The

main features only have been developed, and these imperfectly. Such

being the case, what a world of wonders is the great creation, were we

to consider it only as peopled with insects! What pen could write their

history; what tongue narrate the many marvels of their existence! Ten

thousand times ten thousand, and thousand of thousands, surround us on

every side, accompany us on our excursions, and visit us in our homes,

fill the air with life, and the waters with creeping things.

The history of an insect's life impresses upon us one of the most

consoling truths contained in the word of God. We may learn from the

tale of God's wonders in the vegetable creation, we may find also in

the history of birds, beasts, and fishes, innumerable proofs of His

love, and care, and goodness to all. But these are creatures whose size

in the main renders them conspicuous; too much so, as we might say, to

be overlooked. "Ah! then,"--were there no insects, one might doubtingly

exclaim, "God may take thought for these large creatures, while more

minute beings would be beneath His notice. And so with me: God may

order and arrange the great events in my life; but are not the little

ones too small for Him to regard?" The life of an insect answers these

doubts. It tells us, that though a being be only of the size of a grain

of sand, or not larger than the full stop at the end of this sentence,

God has supplied it with the most beautiful organs; has endowed it with

life, and with the most wonderful instincts, thus manifesting that, in

the words of Scripture, "His care is over all His works." If God, then,

"To whom an atom is an ample field,"

has not thought it beneath Him to take care for such diminutive,

short-lived creatures as these, how much more will He care for His own

people, reconciled to Him through the blood of Jesus, and sanctified

by the Holy Spirit of promise! We are not left, however, to learn this

blessed truth from the page of creation alone. Our Lord has himself

declared to us, that the very hairs of our head are all numbered, and

has left on record the promise, that if we "seek first the kingdom of

God and His righteousness, all these things," that is, all temporal

things, "shall be added unto us."

R. E.

THE END.

R. CLAY, PRINTER, BREAD STREET HILL.

FOOTNOTES:

[A] Vide Frontispiece to this Chapter.

[B] Mr. Rennie.

[C] The definition of the words Caterpillar, Grub, Maggot, as popularly

understood, is as follows:--

A _Caterpillar_ is the larva of a butterfly, moth, or saw-fly, often

hairy, and always provided with a larger or smaller number of legs.

A _Grub_ is the larva of a beetle, having six feet and a smooth body.

A _Maggot_ is the larva of a bee, wasp, or fly, and has no legs.

[D] One of these insects which fell under the writer's notice pierced

and sucked dry aphides of several different species quite indifferently.

[E] This scene is represented in the Frontispiece.

[F] To protect the wine from them it is customary to have little silver

covers for the wine-glasses, which are put on immediately that the

glass is taken from the lips.

[G] Vide "The Life of a Tree."

[H] The insect in the act of squirting is shown in the Frontispiece to

this Part.

[I] Mr. Blackwall has discovered that by carefully examining the _feet_

of spiders, this mistake may be avoided.

[J] M. Bonnet writes of the pupa of a moth, that it can climb up and

down inside its cocoon like a chimney-sweep in a chimney! Some twirl

about inside their cocoons; and it is said that a great entomologist

was once so terrified by the curious noise thus made, that he nearly

threw down the box in which it was, in his alarm.

[K] From a Latin word, signifying "covered," or "disguised."

[L] From a Latin word, signifying "compressed into a small compass."

[M] All pupæ cannot be thus hastened or retarded by influence of

external heat or cold. The pupæ of a moth, very common in our fields,

if all exposed to the same temperature will some of them develop this

year, some the next, and some the year following. This singular fact

cannot be explained.

[N] This scene is depicted in the Frontispiece to the last Part.

[O] Now-a-days the chemist might also answer, _Gutta Percha_; for it

is a singular fact that strong acids have no action upon that curious

substance.

[P] That is, the twelfth part of an inch.

[Q] This scene is represented in the Frontispiece to Part III.

[R] See page 241.

[S] See p. 316.

[T] Several other explanations of red-rain are given, which account for

it by the presence of animalcules, fungi, &c.

[U] Vide the admirable Address of W. Spence, Esq. F.R.S. President of

the Entomological Society for 1849; p. 5.

[V] The proboscis of the carpenter-bee differs from that of the

honey-bee, possessing a curious notched sheath, as represented in the

lower cut.

[W] If we refuse to adopt Dr. Erichson's view of the use of the antennæ.

[X] This plant is a native of South Africa, and a fine specimen of it

exists in the conservatories at Kew. Its botanical name is _Stapelia_.

[Y] The writer has repeated these experiments in a number of cases, and

finds their accuracy confirmed. By cutting off one of the poisers, the

fly is partly crippled, and has a disposition to spin round in flying;

by cutting off both, it is quite unable to fly at all, and becomes

instantly sensible of the loss of apparently a most important pair

of organs, by being so tame as not to try to escape from a touch. A

"Father Long-legs" thus treated had a tendency to fall head foremost,

and also to lie on its back.

[Z] The writer is responsible for these experiments.

[AA] See p. 160.

Transcriber's Note

All paragraphs split by illustrations were rejoined. All obvious

typographical anf formatting errors were corrected.