INSECT PLAGUES AND INSECT SERVICES.
The Universal Dominion of Insects--Mosquitoes--Stinging Flies--
_Œstrus Hominis_--The Chegoe or Jigger--The _Filaria Medinensis_--
The Bête-Rouge--Blood-sucking Ticks--Garapatas--The Land-leeches
in Ceylon--The Tsetsé Fly--The Tsalt-Salya--The Locust--Its
dreadful Devastations--Cockroaches--The Drummer--The Cucarachas
and Chilicabras--Tropical Ants--The Saüba--The Driver Ants--
Termites--Their wonderful Buildings--The Silkworm--The Cochineal--
The Gumlac Insect--Insects used as Food and Ornaments.
The insect tribes may, without exaggeration, be affirmed to hold a kind
of universal empire over the earth and its inhabitants, for nothing
that possesses, or has possessed, life is secure from their attacks.
They vanquish the cunning of the fox, the bulk of the elephant, the
strength of the lion; they plague the reindeer of the northern tundras,
and the antelope of the African wilds; and all the weapons with which
Nature has furnished the higher orders of animals against their
mightier foes prove ineffectual against these puny persecutors, whose
very smallness serves to render them invincible. How numerous are the
sufferings they entail on man! How manifold the injuries they inflict
on his person or his property! To secure himself from their attacks,
a perpetual warfare, an ever-wakeful vigilance, is necessary; for,
though destroyed by thousands, new legions ever make their appearance,
and to repose after a victory is equivalent to a defeat.
In our temperate zone, where a higher cultivation of the ground tends
to keep down the number of the lower animals, their persecutions,
though frequently annoying, may still be borne with patience; but in
many of the tropical regions, where man is either too indolent or not
sufficiently numerous to set bounds to their increase, the insects
constitute one of the great plagues of life.
Along the low river-banks, near stagnant waters, and everywhere on hot
and swampy grounds, the blood-thirsty Mosquitoes appear periodically in
countless multitudes, the dread of all who are exposed to their attacks.
[Illustration: MOSQUITO.]
Not satisfied with piercing the flesh with their sharp proboscis, which
at the same time forms a kind of syphon through which the blood flows,
these malignant gnats, of which there are many species, inject a poison
into the wound, which causes inflammation, and prolongs the pain.
In Angola, Dr. Livingstone found the banks of the river Seuza infested
by legions of the most ferocious mosquitoes he ever met with during the
course of his long travels. ‘Not one of our party could get a snatch
of sleep. I was taken into the house of a Portuguese, but was soon
glad to make my escape, and lie across the path on the lee-side of the
fire, where the smoke blew over my body. My host wondered at my want
of taste, and I at his want of feeling; for, to our astonishment, he
and the other inhabitants had actually become used to what was at least
equal to a nail through the heel of one’s boot, or the tooth-ache.’
‘He who has never sailed on one of the great rivers of tropical
America, the Orinoco, or the Magdalena,’ says Humboldt, ‘can form no
idea of the torments inflicted by the mosquitoes. However accustomed
the naturalist may be to suffer pain without complaining, however his
attention may be riveted by the examination of some interesting object,
he is unavoidably disturbed when Mosquitoes, Zancudos, Zejens, and
Tempraneros cover his hands and face, pierce his clothes, or creep
into his nose and mouth. In the missions of the Orinoco, in these small
villages, situated on the river banks and surrounded by interminable
woods, this plague affords an inexhaustible subject for conversation.
When two people meet in the morning their first questions are--‘How
did the Zancudos behave last night?’ ‘How are the mosquitoes to-day?’
At the mouth of the Red River the unfortunate inhabitants lay down at
night upon the ground, and cover themselves with three or four inches
of sand, so that only the head remains free, over which they spread a
protecting cloth. Above the influx of the Rio Arauca into the Orinoco,
at the cataracts of Baragnon, the atmosphere up to a height of 15 or 21
feet, is filled with a dense mist of stinging insects. Placing oneself
in some dark spot, for instance in one of the deep hollows formed in
the cataracts by mounds of granitic blocks and looking towards the
opening illumined by the sun, one sees whole clouds of mosquitoes,
increasing or diminishing in density as the creatures in their slow
and rhythmic motions now draw more closely together, and then again
separate. In Esmeralda, at the eastern extremity of the Upper Orinoco,
the mosquito clouds are almost as thick as at the cataracts. When the
superior of the monastic order to which the mission belongs, wishes
to punish a lay brother, he sends him to Esmeralda, or, as the monks
facetiously remark, ‘condemns him to the mosquitoes.’
It is a well-known fact that the various species of gnats or flies
comprehended under this general name, do not associate, but appear at
different times of the day. As often as the scene changes or as ‘other
insects mount guard,’ one enjoys a few minutes’ rest; for after the
retreat of one host, its successors are not immediately on the spot.
From half-past six in the morning till five in the afternoon the air is
filled with mosquitoes of the genus Simulium. An hour before sunset,
these are replaced by a small species of Culex called the Tempraneros
or early-risers, as they also show themselves at sunrise. Their stay
in the afternoon scarcely lasts an hour and a half, and then one
feels soon after the painful sting of a larger Culex--the Zancudo--
who, plunging his blood-thirsty proboscis into the skin, causes an
excruciating pain. The Zancudo, a ‘child of the night,’ disappears
at sunrise, and then makes place for the matutinal Tempranero. As all
these winged tormentors spend the greater part of their lives in the
water, we cannot wonder that their numbers diminish as the distance
from the banks of the rivers intersecting the forests increases. Their
favourite resorts are the places where their transformation takes
place, and where they on their part are soon about to lay their eggs.
The mosquito clouds hover only above or near the waters, and it would
be a great error to suppose that the vast forests extending between the
river valleys are all equally infested with this insect plague.
From time to time the mosquitoes migrate like the social stentor
monkeys. Formerly no other Culex was known at Simiti on the Magdalen
river but the small species called Zejen. The people slept unmolested,
for the Zejen is a diurnal insect. But in 1801 the great blue-winged
Zancudo made his appearance in such numbers that the poor inhabitants
of Simiti could find no rest at night.
Slight differences of climate or food seem to have an influence on the
intensity of the poison which the same species discharges through its
serrated proboscis. One cannot refrain from smiling at the disputes
of the missionaries about the size and voracity of the mosquitoes in
different parts of the same river. In a land so completely severed
from the rest of the world, this forms the favourite subject for
conversation. ‘How much I pity you,’ said the missionary from the falls
as he took leave of his colleague at the Cassiquiare; ‘you are like me,
alone in this land of jaguars and monkeys, but as to my mosquitoes I
can boast that one of mine is a match for three of yours.’
This unequal voracity of the insects in different places, this various
intensity of poison in the same species, are very remarkable, but
similar phenomena are met with in the classes of the large animals.
In Angostura the crocodile attacks man, while in New Barcelona people
bathe in his presence without fear. The jaguars on the isthmus of
Panama are cowardly when compared with those of the Upper Orinoco;
and the Indians know very well that the monkeys from one part of the
country can easily be tamed, while individuals of the same species
caught elsewhere will rather die of hunger than submit to captivity.
Whoever has sojourned in a mosquito land knows that there is no radical
remedy against them. The Indians who besmear their body with arnatto or
turtle fat, slap every moment with their flat hands on their shoulders,
back, and legs as often as if they were not painted at all. On the
banks of the Amazons the people use cow-dung burnt at their doors, to
keep away the praya or plague, as they very justly term the mosquitoes.
In the evening every house and cottage has its pan of dung smouldering
in the verandah and emitting rather an agreeable odour--but where the
insects are very numerous and bloodthirsty this fumigation also is of
no avail.
Not content with a passing attack, a South American gadfly (_Œstrus
hominis_) deposits its eggs under the human skin, where the larvæ
continue for six months. If disturbed, they penetrate deeper, and
produce troublesome ulcers, which sometimes even prove fatal. Thus, in
tropical America, we find the same insect tribe which plagues our oxen
and horses, and reduces the northern reindeer to desperation, settle on
man himself, and render even the lord of creation subject to its power.
The Chegoe, Pique, or Jigger of the West Indies (_Pulex penetrans_) is
another great torment of the hot countries of America.
It looks exactly like a small flea, and a stranger would take it for
one. However, in about four and twenty hours he would have several
broad hints that he had made a mistake in his ideas of the animal.
Without any respect for colour, it attacks different parts of the body,
but chiefly the feet, betwixt the toe-nails and the flesh. There it
buries itself and causes an itching, which at first is not unpleasant,
but after a few days gradually increases to a violent pain. At the same
time a small white tumour, about the size of a pea, and with a dark
spot in the centre, rises under the skin. The tumour is the rapidly
growing nest of the chegoe, the spot the little plague itself. And now
it is high time to think of its extirpation, an operation in which
the negro women are very expert. Gently removing with a pin the skin
from the little round white ball or nest, precisely as we should peel
an orange, and pressing the flesh all round, they generally succeed
in squeezing it out without breaking, and then fill the cavity with
snuff or tobacco, to guard against the possibility of a fresh colony
being formed by some of the eggs remaining in the wound. New comers
are particularly subject to these creatures. Waterton, who by practice
appears to have become very expert in eradicating chegoes’ nests, once
took four out of his feet in the course of the day, and a negress
extracted no less than eighty-three out of Richard Schomburgk’s toes in
one sitting. ‘Every evening,’ says the venerable naturalist of Walton
Hall, ‘before sundown, it was part of my toilet to examine my feet and
see that they were clear of chegoes. Now and then a nest would escape
the scrutiny, and then I had to smart for it a day or two after. A
chegoe once lit upon the back of my hand: wishful to see how he worked,
I allowed him to take possession. He immediately set to work head
foremost, and in about half an hour he had completely buried himself in
the skin. I then let him feel the point of my knife, and exterminated
him.’
If the prompt extraction of the chegoes’ nests is neglected, the
worm-like larvæ creep out, continue the mining operations of their
parent, and produce a violent inflammation, which may end in the
mortification of a limb. It not unfrequently happens that negroes from
sheer idleness or negligence in the first instance have been lamed
for life and become loathsome to the sight. In such a state, these
miserable objects are incurable, and death only puts an end to their
sufferings.
A still more dangerous plague, peculiar to the coast of Guinea and the
interior of tropical Africa, to Arabia, and the adjacent countries,
is the _Filaria medinensis_ of Linnæus. This dreaded worm comes to
the herbage in the morning dew, from whence it pierces the skin, and
enters the feet of such as walk without shoes, causing the most painful
irritation, succeeded by violent inflammation and fever. The natives
extract it with the greatest caution by twisting a piece of silk
round one extremity of the body and withdrawing it very gently. When
we consider that this insidious worm is frequently twelve feet long,
although not thicker than a horse-hair, we can readily imagine the
difficulty of the operation. If unfortunately the animal should break,
the part remaining under the skin grows with redoubled vigour, and
frequently occasions a fatal inflammation.
One of these most unwelcome intruders once entered Dampier’s ankle. ‘I
was in great torment,’ says this entertaining traveller, ‘before it
came out. My leg and ankle swelled, and looked very angry, and I kept
on a plaster to bring it to a head. At last, drawing off my plaster,
out came three inches of the worm, and my pain abated. Till that time I
was ignorant of my malady, and a gentleman at whose house I was took it
for a nerve; but I knew well what it was, and presently rolled it up on
a small stick. After this I opened the place every morning and evening,
and strained the worm out gently, about two inches at a time--not
without some pain--till I had at length got it out.’
Among the plagues of Guiana and the West Indies we must not forget a
little insect in the grass and on the shrubs, which the French call
bête-rouge. It is of a beautiful scarlet colour, and so minute that you
must bring your eye close to it before you can perceive it. It abounds
most in the rainy season. Its bite causes an intolerable itching,
which, according to Richard Schomburgk, who writes from personal
experience, drives by day the perspiration of anguish from every pore,
and at night makes one’s hammock resemble the gridiron on which Saint
Lawrence was roasted. The best way to get rid of the plague is to
rub the part affected with lemon-juice or rum. ‘You must be careful
not to scratch it,’ says Waterton. ‘If you do so and break the skin,
you expose yourself to a sore. The first year I was in Guiana the
bête-rouge and my own want of knowledge, and, I may add, the little
attention I paid to it, created an ulcer above the ankle which annoyed
me for six months, and if I hobbled out into the grass, a number of
bête-rouges would settle on the edges of the sore and increase the
inflammation.’
The blood-sucking Ticks are also to be classed among the intolerable
nuisances of many tropical regions. A large American species called
Garapata (_Ixodes sanguisuga_) fixes on the legs of travellers,
and gradually buries its whole head in the skin, which the body,
disgustingly distended with blood, is unable to follow. On being
violently removed, the former remains in the wound, and often produces
painful sores. The Indians returning in the evening from the forest or
from their field labour generally bring some of these creatures along
with them, swollen to the size of hazel nuts.
Though countless hosts of ticks infest the Ceylonese jungle, though
mosquitoes without number swarm over the lower country, yet the
land-leeches which beset the traveller in the rising grounds are a
still more detested plague. ‘They are not frequent in the plains,’
says Sir E. Tennent, ‘which are too hot and dry for them; but amongst
the rank vegetation in the lower ranges of the hill-country, which is
kept damp by frequent showers, they are found in tormenting profusion.
They are terrestrial, never visiting ponds or streams. In size they are
about an inch in length, and as fine as a common knitting needle, but
capable of distention till they equal a quill in thickness and attain a
length of nearly two inches. Their structure is so flexible that they
can insinuate themselves through the meshes of the finest stocking,
not only seizing on the feet and ankles, but ascending to the back and
throat, and fastening on the tenderest parts of the body. The coffee
planters who live amongst these pests are obliged in order to exclude
them, to envelope their legs in “leech gaiters,” made of closely woven
cloth.
‘In moving, the land-leeches have the power of planting one extremity
on the earth and raising the other perpendicularly to watch for their
victim. Such is their vigilance and instinct that, on the approach of
a passer-by to a spot which they infest, they may be seen amongst the
grass and fallen leaves, on the edge of a native path, poised erect,
and preparing for their attack on man and horse. On descrying their
prey they advance rapidly by semicircular strides, fixing one end
firmly and arching the other forwards, till by successive advances they
can lay hold of the traveller’s foot, when they disengage themselves
from the ground and ascend his dress in search of an aperture to
enter. In these encounters the individuals in the rear of a party of
travellers in the jungle invariably fare worst, as the leeches once
warned of their approach congregate with singular celerity. Their size
is so insignificant, and the wound they make so skilfully punctured,
that the first intimation of their onslaught is the trickling of the
blood, or a chill feeling of the leech when it begins to hang heavily
on the skin from being distended by its repast. Horses are driven
wild by them, and stamp the ground in fury to shake them from their
fetlocks, to which they hang in bloody tassels. The bare legs of the
palankin-bearers and coolies are a favourite resort, and their hands
being too much engaged to be spared to pull them off, the leeches
hang like bunches of grapes round their ankles; and I have seen the
blood literally flowing over the edge of a European’s shoe from
their innumerable bites. In healthy constitutions the wounds, if not
irritated, generally heal, occasioning no other inconvenience than
a slight inflammation and itching; but in those with a bad state of
body, the punctures, if rubbed, are liable to degenerate into ulcers,
which may lead to the loss of limb or of life. Both Marshall and Davy
mention that, during the march of the troops in the mountains, when the
Kandyans were in rebellion, in 1818, the soldiers, and especially the
Madras Sepoys, with the pioneers and coolies, suffered so severely from
this cause that numbers of them perished.’
[Illustration: THE TSETSÉ.]
Among the many noxious insects destructive to the property of man,
there is, perhaps none more remarkable than the South African
Tsetsé-fly (_Glossīna morsitans_), whose peculiar buzz when once heard
can never be forgotten by the traveller whose means of locomotion are
domestic animals; for it is well known that the bite of this poisonous
insect is certain death to the ox, horse, and dog. Fortunately it
is limited to particular districts, frequently infesting one bank
of a river while the other contains not a single specimen, or else
travelling in South Africa would be utterly impossible, and we should
now know no more of Lake Ngami or the Zambesi than we did thirty years
since. In one journey Dr. Livingstone lost no less than forty-three
fine oxen by the bite of the tsetsé. A party of Englishmen once
attempted to reach Libebé, but they had only proceeded seven or eight
days’ journey to the north of the Ngami, when both horses and cattle
were bitten by the fly, and the party were in consequence compelled to
make a hasty retreat. One of the number was thus deprived of as many as
thirty-six horses, excellent hunters, and all sustained heavy losses in
cattle.
A most remarkable feature in the bite of the tsetsé is its perfect
harmlessness in man and wild animals, and even calves, so long as
they continue to suck the cow. The mule, ass, and goat enjoy likewise
the same immunity, and many large tribes on the Zambesi can keep no
domestic animals except the latter, in consequence of the scourge
existing in their country. Dr. Livingstone’s children were frequently
bitten, yet suffered no harm, and he saw around him numbers of zebras,
buffaloes, pigs, pallahs and other antelopes, feeding quietly in the
very habitat of the tsetsé, yet as undisturbed by its bite as oxen are
when they first receive the fatal poison, which acts in the following
manner. After a few days the eyes and nose begin to run, the coat
stares as if the animal were cold, a swelling appears under the jaw,
and, though the animal continues to graze, emaciation commences,
accompanied with a peculiar flaccidity of the muscles; and this
proceeds unchecked until, perhaps months afterwards, purging comes on,
and the animal, no longer able to graze, perishes in a state of extreme
exhaustion. Those which are in good condition often perish, soon after
the wound is inflicted, with staggering and blindness, as if the brain
were affected by it. Sudden changes of temperature, produced by falls
of rain, seem to hasten the progress of the complaint, but in general
the emaciation goes on uninterruptedly for months; and do what one may,
the poor animals perish miserably, as there is no cure yet known for
the disease.
Had any one of our indigenous flies similar poisonous qualities we
should never have been able to escape from barbarism; if, by any fatal
chance, the tsetsè were to settle among us, our prosperity would soon
be at an end, and our civilisation imperilled! Reflections such as
these are well calculated to humble our pride and check our presumption!
The Abyssinian Tsalt-salya or Zimb, described by Bruce, seems identical
with the tsetsè, or produces at least similar symptoms. At the season
when this plague makes its appearance, all the inhabitants along the
sea-coast, from Melinde to Cape Gardafui, and to the south of the Red
Sea, are obliged to retire with their cattle to the sandy plains to
preserve them from destruction.
The French traveller, D’Escayrac, tells us of a fly in Soudan which
leaves the ox uninjured but destroys the dromedary. On account of this
plague the camel is confined to the northern boundary of the Soudan,
while the oxen graze in safety throughout the whole country. This fly
has caused more migrations among the Arabs of the Soudan than all their
wars; and in the dry season it even drives the elephant from Lake Tsad
by flying into its ears.
[Illustration: LOCUST.]
Though the locusts not seldom extend their ravages to the steppes of
southern Russia, though they have been known to burst like a cloud
of desolation over Transylvania and Hungary, and stray stragglers
now and then even find their way to England, yet their chief habitat
and birthplace is the torrid zone. They wander forth in countless
multitudes, and at very irregular periods; but how it comes that
they are multiplied to such an excess in particular years and not in
others, has never yet been ascertained, and perhaps never will be.
They are armed with two pairs of strong mandibles; their stomach is of
extraordinary capacity and power; they make prodigious leaps by means
of their muscular and long hind legs; and their wings even carry them
far across the sea. On viewing a single locust, one can hardly conceive
how they can cause such devastation, but the wonder ceases on hearing
of their numbers.
Mahomet--so say his followers--once read upon the wing of a locust:
‘We are the army of God; we lay ninety-nine eggs; and if we laid a
hundred, we should devour the whole earth and all that grows upon
its surface.’ ‘O Allah!’ exclaimed the terrified prophet, ‘Thou who
listenest patiently to the prayers of Thy Servant, destroy their young,
kill their chieftains, and stop their mouths, to save the Moslems’
food from their teeth!’ Scarce had he spoken when the angel Gabriel
appeared, saying, ‘God grants thee part of thy wishes.’ And, indeed,
as all true believers know, this prayer of their prophet, written on a
piece of paper, and enclosed in a reed which is stuck in the ground, is
sure to preserve a field or an orchard from locust devastation.
As a locust host advances, its columns are sometimes seen rising in
compact bodies as if propelled by a strong gust of wind; then, suddenly
sinking, they disperse into smaller battalions, not unlike vapours
floating about a hill-side at early morn, and when slightly agitated
by a breeze; or they resemble huge columns of sand or smoke, changing
their shape every minute.
Onward they come--a dark continuous cloud
Of congregated myriads, numberless;
The rushing of whose wings is as the sound
Of a broad river headlong in its course,
Plunged from a mountain summit; or the roar
Of a wild ocean in the autumn storm,
Shattering its billows on a shore of rocks!--SOUTHEY.
During their flight numbers are constantly alighting--an action which
has not inaptly been compared to the falling of large snow-flakes. It
is, however, not until the approach of night that the locusts encamp.
Woe to the spot they select as a resting-place! The sun sets on a
landscape green with all the luxuriance of tropical vegetation; it
rises in the morning over a region naked as the waste of the Sahara!
The locust is fierce, and strong, and grim,
And an armèd man is afraid of him;
He comes like a wingèd shape of dread,
With his shielded back, and his armèd head;
And his double wings for hasty flight,
And a keen unwearying appetite.
He comes with famine and fear along;
An army a million, million strong.
The Goth and the Vandal, and the dwarfish Hun
With their swarming people, wild and dun,
Brought not the dread that the locust brings,
When is heard the rush of their myriad wings.
From the deserts of burning sand they speed,
Where the lions roam, and the serpents breed.
Far over the sea, away, away!
And they darken the sun at noon of day.
Like Eden the land before they find,
But they leave it a desolate waste behind.
The peasant grows pale when he sees them come,
And standeth before them, weak and dumb,
For they come like a raging fire in power,
And eat up a harvest in half an hour;
And the trees are bare, and the land is brown,
As if trampled and trod by an army down.
There is terror in every monarch’s eye,
When he hears that this terrible foe is nigh;
For he knows that the might of an armèd host
Cannot drive the spoiler from out his coast:
That terror and famine his land await,
And from north to south ‘twill be desolate.
Thus the ravening locust is strong and grim,
And what were an armèd man to him?
Fire turneth him not, nor sea prevents,
He is stronger by far than the elements.
The broad green earth is his prostrate prey,
And he darkens the sun at noon of day.--MARY HOWITT.
The tropical plague of the cockroaches has been introduced into
England; but, fortunately, the giant of the family, the _Blatta
gigantea_, a native of many of the warmer parts of Asia, Africa, and
South America, is a stranger to our land: and the following truthful
description of this disgusting insect gives us every reason to be
thankful for its absence:--‘They plunder and erode all kinds of
victuals, dressed and undressed, and damage all sorts of clothes,
especially such as are touched with powder, pomatum, and similar
substances; everything made of leather; books, paper, and various other
articles, which if they do not destroy, at least they soil, as they
frequently deposit a drop of their excrement where they settle, and,
some way or other, by that means damage what they cannot devour. They
fly into the flame of candles, and sometimes into the dishes; are very
fond of ink and of oil, into which they are apt to fall and perish, in
which case they soon turn most offensively putrid--so that a man might
as well sit over the cadaverous body of a large animal as write with
the ink in which they have died. They often fly into persons’ faces
or bosoms, and their legs being armed with sharp spines, the pricking
excites a sudden horror not easily described. In old houses they swarm
by myriads, making every part filthy beyond description wherever they
harbour, which in the daytime is in dark corners, behind clothes--in
trunks, boxes, and, in short, every place where they can lie concealed.
In old timber and deal houses, when the family is retired at night
to sleep, this insect, among other disagreeable properties, has the
power of making a noise which very much resembles a pretty smart
knocking with the knuckle upon the wainscoting. The _Blatta gigantea_
in the West Indies is therefore frequently known by the name of _the
drummer_. Three or four of these noisy creatures will sometimes be
impelled to answer one another, and cause such a drumming noise that
none but those who are very good sleepers can rest for them. What is
most disagreeable, those who have not gauze curtains are sometimes
attacked by them in their sleep; the sick and dying have their
extremities attacked; and the ends of the toes and fingers of the dead
are frequently stripped both of the skin and flesh.’
According to Tschudi, the cucaracha and chilicabra--two large species
of the cockroach--infest Peru in such numbers as almost to reduce
the inhabitants to despair. Greedy, bold, cunning, they force their
way into every hut, devour the stores, destroy the clothes, intrude
into the beds and dishes, and defy every means that is resorted to
for their destruction. Fortunately, they are held in check by many
formidable enemies, particularly by a small ant, and a pretty little
bird (_Troglodytes audax_) belonging to the wagtail family, which has
some difficulty in mastering the larger cockroaches. It first of all
bites off their head, and then devours their body, with the exception
of their membranaceous wings. After having finished his repast, the
bird hops upon the nearest bush, and there begins his song of triumph.
Many other insect plagues might be added to the list, but those I have
already enumerated suffice to reconcile us to our misty climate, and to
diminish our longing for the palm groves of the torrid zone.
Rivalling the mosquitoes in the art of tormenting man, and perhaps even
surpassing them in numbers, the equatorial ants may truly be said to
hold a despotic sway over the forest and the savannah, over the thicket
and the field. It is hardly possible to penetrate into a tropical wood
without being reminded, by their stings and bites, that they consider
the visit as an intrusion, while they themselves unceremoniously invade
the dwellings of man, and lay ruinous contributions on his stores.
The inconceivable number of their species defies the memory of the
naturalist, to whom many are even still entirely unknown. From almost
microscopical size to an inch in length, of all colours and shades
between yellow, red, brown, and black, of the most varied habits and
stations, the ants of a single tropical land would furnish study
for years to a zealous entomologist. Every family of plants has its
peculiar species, and many trees are even the exclusive dwelling-place
of some ant nowhere else to be found. In the scathes of leaves, in the
corollas of flowers, in buds and blossoms, over and under the earth, in
and out of doors, one meets these ubiquitous little creatures, which
are undoubtedly one of the great plagues of the torrid zone.
While our indigenous ants cause a disagreeable burning on the skin, by
the secretion of a corrosive acid peculiar to the race, the sting or
bite of many tropical species causes the most excruciating tortures. ‘I
have no words,’ says Schomburgk, ‘to describe the pain inflicted upon
me by the mandibles of the Ponera clavata, a large, and, fortunately,
not very common ant, whose long black body is beset with single hairs.
Like an electric shock the pain instantly shot through my whole body,
and soon after acquired the greatest intensity in the breast, and over
and under the armpits. After a few minutes I felt almost completely
paralysed, so that I could only with the greatest difficulty, and under
the most excruciating tortures, totter towards the plantation, which,
however, it was impossible for me to reach. I was found senseless on
the ground, and the following day a violent wound fever ensued.’
‘Having, while in Angola, accidentally stepped upon a nest of red
ants,’ says Livingstone, ‘not an instant seemed to elapse before a
simultaneous attack was made on various unprotected parts, up the
trousers from below, and on my neck and breast above. The bites of
these furies were like sparks of fire, and there was no retreat. I
jumped about for a second or two, then in desperation tore off all
my clothing, and rubbed and picked them off seriatim as quickly as
possible! Fortunately, no one observed this rencontre, or word might
have been taken back to the village that I had become mad. It is really
astonishing how such small bodies can contain so large an amount of
ill nature. They not only bite, but twist themselves round after the
mandibles are inserted, to produce laceration and pain more than would
be effected by the single wound. Frequently, while sitting on the ox,
as he happened to tread near a band, they would rush up his legs to the
rider, and soon let him know that he had disturbed their march. They
possess no fear, attacking with equal ferocity the largest as well as
the smallest animals. When any person has leaped over the band, numbers
of them leave the ranks and rush along the path, seemingly anxious for
a fight.’
But however formidable the weapons of the ants may be, yet the injuries
they inflict upon the property of man, pouring over his plantations
like a flood, and sweeping away the fruits of his labours, are of
a much more lasting and serious nature than their painful bite or
venomous sting.
In the West Indies, the brown-black Viviagua, about one-third of
an inch long, and with a prickly thorax, is the greatest enemy of
the coffee plantations. In one day it will rob a full-grown tree of
all its leaves. It digs deep subterranean passages of considerable
dimensions and irregular forms, with a great number of hand-high
galleries branching out from the sides, and does even more harm to the
coffee-plants by its mining operations than by robbing them of their
foliage.
Other species are no less destructive to the sugar plantations, either
by settling in the interior of the stalks or by undermining the roots
so that the plant becomes sickly and dies.
The Saüba or Coushie (_Œcodoma cephalotes_), a species of ant
distinguished by its large head, is the most formidable enemy of the
banana and cassava plantations. Such are its numbers that in a very
short time it will strip off the leaves of an entire field. Even where
their nest is a mile distant from a plantation, these arch depredators
know how to find it, and soon form a highway, about half a foot broad,
on which they keep up the most active communications with the object
of their attack. In masterly order, side by side, one army is seen to
move onwards towards the field, while another is returning to the nest.
In this last column each individual carries a round piece of leaf,
about the size of a sixpence, which is held by one of its edges. If
the distance is too great, a party meets the weary carriers half way,
and relieves them of their load. Although innumerable ants may thus be
moving along, yet none of them will ever be seen to be in the other’s
way; and all goes on with the regularity of clock-work.
A third party is no less actively employed on the scene of destruction,
cutting out circular pieces of the leaves, which, as soon as they
drop upon the ground, are immediately seized by the attentive and
indefatigable carriers. Neither fire nor water can prevent them from
proceeding with their work. Though thousands may be killed, yet in less
than an hour all the bodies will have been removed. Should the highway
be closed by an insurmountable obstacle, another is soon laid out, and
after a few hours the operations, momentarily disturbed, resume their
former activity.
The use of the leaves is to thatch the curious domelike edifices which
these indefatigable builders raise over their burrows, and to prevent
the loose earth from falling in. Some of these domes are of gigantic
dimensions, measuring two feet in height and forty feet in diameter--
a prodigious size when compared with the puny proportions of the tiny
architects that raise them. Division of labour is carried on to a
wonderful extent in these buildings, for the labourers who fetch the
leaves do not place them, but merely fling them down on the ground,
when they are picked up by a relay of workers who lay them in their
proper order. As soon as they have been properly arranged they are
covered with small pellets of earth, and in a very short time they are
quite hidden by their earthy covering. From these domes cylindrical
shafts lead down into the mysterious recesses of the burrows, whose
subterranean galleries are so vast and complicated that they have never
been fully investigated. Some idea of their extent may be formed from
the fact that sulphur smoke having been blown into a nest, one of the
outlets was detected at a distance of seventy yards.
Not satisfied with devouring his harvests, the tropical ants leave man
no rest even within doors, and trespass upon his household comforts in
a thousand various ways.
In Mainas, a province on the Upper Amazon, Professor Pöppig counted no
less than seven different species of ants among the tormenting inmates
of his hut. The diminutive red Amache was particularly fond of sweets.
Favoured by its smallness, it penetrates through the imperceptible
openings of a cork, and the traveller was often obliged to throw away
the syrup which in that humid and sultry country replaces the use of
crystallised sugar, from its having been changed into an ant-comfit.
This troublesome lover of sweets lives under the corner-posts of the
hut, so that it is quite impossible to dislodge him.
The devastations of the house-ants are peculiarly hateful to the
naturalist, whose collections, often gathered with so much danger
and trouble, they pitilessly destroy. Richard Schomburgk suspended
boxes with insects from the ceiling by threads strongly rubbed over
with arsenic soap; but when, on the following morning, he wished to
examine his treasures, instead of his rare and beautiful specimens he
found nothing but a host of villanous red ants, who crawling down the
threads, had found means to invade the boxes and utterly to destroy
their valuable contents.
[Illustration: FORAGING ANTS.]
In countless multitudes the Driver or Foraging ants break forth from
the primeval forest, marching through the country in compact order,
like a well-drilled army. Every creature they meet in their way falls
a victim to their dreadful onslaught--rats, mice, lizards, and even
the huge python, when in a state of surfeit from recent feeding. If a
house obstructs their route, they do not turn out of the way, but go
quite through it. Though they sting cruelly when molested, the West
Indian planter is not sorry to see them in his house, for it is but a
passing visit, and their appearance is the death-warrant for every
spider, scorpion, cockroach, or reptile that pollutes his dwelling.
Unfortunately, this thorough cleansing is but of short duration, as in
less than a week tropical life calls forth a new generation of vermin.
The wonderful societies of the ants, their strength and perseverance,
their unwearied industry, their astonishing intelligence, are so well
known, and have been so often and so admirably described[22], that it
would be trespassing on the patience of my readers were I to enter into
any lengthened details on the subject. And yet, the observations of
naturalists have chiefly been confined to the European species, while
the economy of the infinitely more numerous tropical ants, confined to
countries or places hardly ever visited, or even unknown to civilised
man, remains an inexhaustible field for future inquiry.
[Illustration: FUNGUS ANT.]
The study of their various buildings alone, from the little we know of
them, would occupy a zealous entomologist for years. Here we have an
American species that forms its globular nest of the size of a large
Dutch cheese, of small twigs artistically interlaced; there another,
which (_Formica bispinosa_) uses cotton for its building material, and
through the chemical agency of its pungent secretion converts it into
a spongy substance.
On the west coast of Borneo, Mr. Adams noticed two kinds of ants’
nests--one species of the size of a man’s hand, adhering to the
trunk of trees resembling, when cut through, a section of the lungs;
the other was composed of small withered bits of sticks and leaves,
heaped up in the axils of branches, somewhat in the form of flattened
cylinders and compressed cones. A third species, still more ingenious,
constructs its domicile out of a large leaf, bending the two halves by
the weight of united millions till the opposite margins meet at the
under surface of the mid-rib, where they are secured by a gummy matter.
The stores and larvæ are conveyed into the nest so made by regular
beaten tracks along the trunk and branches of the tree.
On the large plains near Lake Dilolo, where water stands so long
annually as to allow the lotus and other aqueous plants to come to
maturity, Dr. Livingstone had occasion to admire the wonderful sagacity
of the ants, whom he declares to be wiser than some men, as they learn
by experience. When all the land is submerged a foot deep, they manage
to exist by ascending to little houses, built of black tenacious loam,
on stalks of grass, and placed higher than the line of inundation.
This must have been the result of experience, for if they had waited
till the water actually invaded their habitations on the ground,
they would not have been able to procure materials for their higher
quarters, unless they dived down to the bottom for every mouthful of
clay. They must have been built in anticipation, ‘and if so,’ says the
celebrated traveller, ‘let us humbly hope that the sufferers by the
late inundations in France may be possessed of as much common sense as
the little black ants of the Dilolo plains.’
Unable or unwilling to work themselves, some species of ants make war
upon others for the sole purpose of procuring bondsmen, who literally
and truly labour for them, and perform all the domestic duties of the
community; but the Mexican honey ants (_Myrmecocystus Mexicanus_) are,
if possible, still more remarkable, for here we see an animal rearing
others of the same species for the purpose of food. Some of these ants,
namely, are distinguished by an enormous swelling of the abdomen,
which is converted into a mass like honey, and being unable, in their
unwieldly condition, to seek food themselves, are fed by the labourers,
until they are doomed to die for the benefit of the community. Whether
this vast distension is the result of an intestinal rupture, caused by
an excessive indulgence of the appetite, or whether they are purposely
selected, confined, and over-fed, or wounded for the purpose, has not
yet been ascertained.
The termites, or white ants, as they are commonly called, though
they in reality belong to a totally different order of insects, are
spread in countless numbers over all the warmer regions of the earth,
emulating on the dry land the bore-worm in the sea; for when they
have once penetrated into a building, no timber except ebony and
iron-wood, which are too hard, or such as is strongly impregnated with
camphor and aromatic oils, which they dislike, is capable of resisting
their attacks. Their favourite food is wood, and so great are their
multitudes, so admirable their tools, that in a few days they devour
the timberwork of a spacious apartment. Outwardly, the beams and
rafters may seem untouched, while their core is completely consumed,
for these destructive miners work in the dark, and seldom attack the
outside until they have previously concealed themselves and their
operations by a coat of clay. Scarcely any organic substance remains
free from their attacks; and forcing their resistless way into trunks,
chests, and wardrobes, they will often devour in one night all the
shoes, boots, clothes, and papers they may contain. It is principally
owing to their destructions, says Humboldt, that it is so rare to find
papers in tropical America of an older date than fifty or sixty years.
Smeathman relates, that a party of them once took a fancy to a pipe of
fine old Madeira, not for the sake of the wine, almost the whole of
which they let out, but of the staves, which, however, may not have
proved less tasteful from having imbibed some of the costly liquor.
On surveying a room which had been locked up during an absence of a
few weeks, Forbes, the author of the ‘Oriental Memoirs,’ observed a
number of advanced works in various directions towards some prints and
drawings in English frames; the glasses appeared to be uncommonly dull,
and the frames covered with dust. On attempting to wipe it off, he was
astonished to find the glasses fixed to the wall, not suspended in
frames as he left them, but completely surrounded by an incrustation
cemented by the white ants, who had actually eaten up the deal frames
and backboards and the greater part of the paper, and left the glasses
upheld by the incrustation or covered way which they had formed during
their depredations.
On the small island of Goree, near Cape Verde, the French naturalist,
Adanson, lived in a straw hut, which, though quite new at the time he
took up his residence in it, became transparent in many places before
the month was out. This might have been endured, but the villanous
termites ravaged his trunk, destroyed his books, penetrated into his
bed, and at last attacked the naturalist himself. Neither sweet nor
salt water, neither vinegar nor corrosive liquids, were able to drive
them away, and so Adanson thought it best to abandon the premises, and
to look out for another lodging.
The ravages of the termites are, however, perhaps more than compensated
by their services in removing decayed vegetable substances from the
face of the earth, and thus contributing to the purity of the air and
the beauty of the landscape. If the forests of the tropical world,
where thousands of gigantic trees succumb to the slow ravages of time,
or are suddenly prostrated by the hurricane, still appear in all the
verdure of perpetual youth, it is chiefly to the unremitting labours of
the termites that they are indebted for their freshness.
Though belonging to a different order of the insect world, the economy
of the termites is very similar to that of the real ants. They also
form communities, divided into distinct orders; labourers (larvæ),
soldiers (neuters), perfect insects--and they also erect buildings,
but of a far more astonishing structure. Several of their species (_T.
atrox, bellicosus_ Smeathman) erect high dome-like edifices, rising
from the plain, so that at first sight they might be mistaken for the
hamlets of the negroes; others (_T. destructor arborum_) build on
trees, often at a considerable height above the ground. These sylvan
abodes are frequently the size of a hogshead, and are more generally
found in the New World.
[Illustration: TERMITE HILLS.]
The clay-built citadels or domes of the _Termes bellicosus_, a common
species on the West Coast of Africa, attain a height of twelve feet,
and are constructed with such strength that the traveller often ascends
them to have an uninterrupted view of the grassy plain around.
Only the under part of the mound is inhabited by the white ants, the
upper portion serving principally as a defence from the weather, and
to keep up in the lower part the warmth and moisture necessary to the
hatching of the eggs and cherishing of the young ones. In the centre,
and almost on a level with the ground, is placed the sanctuary of the
whole community--the large cell, where the queen resides with her
consort, and which she is doomed never to quit again, after having
been once enclosed in it, since the portals soon prove too narrow
for her rapidly-increasing bulk. Encircling the regal apartment,
extends a labyrinth of countless chambers, in which a numerous army of
attendants and soldiers is constantly in waiting. The space between
these chambers and the external wall of the citadel is filled with
other cells, partly destined for the eggs and young larvæ, partly for
store-rooms. The subterranean passages which lead from the mound are
hardly less remarkable than the building itself. Perfectly cylindrical,
and lined with a cement of clay, similar to that of which the hill
is formed, they sometimes measure a foot in diameter. They run in a
sloping direction, under the bottom of the hill, to a depth of three
or four feet, and then ramifying horizontally into numerous branches,
ultimately rise near to the surface at a considerable distance. At
their entrance into the interior of the hill, they are connected with a
great number of smaller galleries, which, gradually winding round the
whole building to the top, intersect each other at different heights.
The necessity for the vast size of the main galleries underground,
evidently arises from the circumstance of their being the great
thoroughfares for the inhabitants, by which they fetch their clay,
wood, water, or provisions, and their gradual ascent is requisite, as
the Termites can only with great difficulty climb perpendicularly.
It may be imagined that such works require an enormous population
for their construction; and, indeed, the manner in which an infant
colony of termites is formed and grows, until becoming, in its turn,
the parent of new migrations, is not the least wonderful part of this
wonderful insect’s history.
At the end of the dry season, as soon as the first rains have fallen,
the male and female perfect termites, each about the size of two
soldiers, or thirty labourers, and furnished with four long narrow
wings folded on each other, emerge from their retreats in myriads.
After a few hours their fragile wings fall off, and on the following
morning they are discovered covering the surface of the earth and
waters, where their enemies--birds, reptiles, ants--cause so sweeping
a havoc that scarce one pair out of many thousands escapes destruction.
If by chance the labourers, who are always busy prolonging their
galleries, happen to meet with one of these fortunate couples, they
immediately, impelled by their instinct, elect them sovereigns of a new
community, and, conveying them to a place of safety, begin to build
them a small chamber of clay, their palace and their prison--for
beyond its walls they never again emerge.
[Illustration: TERMITE.]
Soon after the male dies, but, far from pining and wasting over the
loss of her consort, the female increases so wonderfully in bulk that
she ultimately weighs as much as 30,000 labourers, and attains a length
of three inches, with a proportional width. This increase of size
naturally requires a corresponding enlargement of the cell, which is
constantly widened by the indefatigable workers. Having reached her
full size, the queen now begins to lay her eggs, and as their extrusion
goes on uninterruptedly, night and day, at the rate of fifty or sixty
in a minute, for about two years, their total number may probably
amount to more than fifty millions! A wonderful fecundity, which
explains how a termite colony, originally few in number, increases in a
few years to a population equalling or surpassing that of the British
empire.
This incessant extrusion of eggs necessarily calls for the attention
of a large number of the workers in the royal chamber, to take them
as they come forth, and carry them to the nurseries, in which, when
hatched, they are provided with food, and carefully attended till they
are able to shift for themselves, and become in their turn useful to
the community.
In widening their buildings according to the necessities of their
growing population, from the size of small sugar-loaves to that of
domes which might be mistaken for the hovels of Indians or negroes,
as well as in repairing their damages, the termite workers display an
unceasing and wonderful activity, while the soldiers, or neuters, which
are in the proportion of about one to every hundred labourers, and
are at once distinguished by the enormous size of their heads armed
with long and sharp jaws, are no less remarkable for their courage and
energy.
When anyone is bold enough to attack their nest and make a breach in
its walls, the labourers, who are incapable of fighting, immediately
retire, upon which a soldier makes his appearance, obviously for
the purpose of reconnoitring, and then also withdraws to give the
alarm. Two or three others next appear, scrambling as fast as they
can one after the other; to these succeed a large body, who rush
forth with as much speed as the breach will permit, their numbers
continually increasing during the attack. These little heroes present
an astonishing, and at the same time a most amusing spectacle. In their
haste they frequently miss their hold, and tumble down the sides of
their hill; they soon, however, recover themselves, and being blind,
bite everything they run against. If the attack proceeds, the bustle
increases to a tenfold degree, and their fury is raised to its highest
pitch. Woe to him whose hands or legs come within their reach, for they
will make their fanged jaws meet at the very first stroke, drawing
their own weight in blood, and never quitting their hold, even though
they are pulled limb from limb. The courage of the bulldog is as
nothing compared to the fierce obstinacy of the termite-soldier.
[Illustration: SOLDIER.]
So soon as the injury has ceased, and no further interruption is given,
the soldiers retire, and then you will see the labourers hastening in
various directions towards the breach, each carrying in his mouth a
load of tempered mortar half as big as himself, which he lays on the
edge of the orifice, and immediately hastens back for more. Not the
space of the tenth part of an inch is left without labourers working
upon it at the same moment; crowds are constantly hurrying to and
fro; yet, amid all this activity, the greatest order reigns--no one
impedes the other, but each seems to thread the mazes of the multitude
without trouble or inconvenience. By the united labours of such an
infinite host the ruined wall soon rises again; and Mr. Smeathman has
ascertained that in a single night they will restore a gallery of three
or four yards in length.
In numbers and architectural industry the American Termites are
not inferior to those of the Old World. In the savannahs of Guiana
their sugar-loaf or mushroom-shaped, pyramidal or columnar hills are
everywhere to be seen, impenetrable to the rain, and strong enough to
resist even a tropical tornado. On the summits of these artificial
mounds a neat little falcon (_Falco sparverius_) often takes his
station, darting down, from time to time, like lightning upon some
unfortunate lizard, and then again speedily returning to his look-out.
The large caracara eagle (_Polyborus caracara_) likewise chooses these
eminences as an observatory from whence he rushes robber-like on his
prey; there also an ugly black lizard (_Ecchymotes torquatus_) loves
to sun itself, but disappears immediately in the grass as soon as a
traveller approaches.
In many parts of the Brazilian campos or savannahs the termite-hills,
which are there generally of a more flattened form, are so numerous
that one is almost sure to meet with one of them at the distance of
every ten or twenty paces. The great ant-bear digs deep holes into
their sides, where afterwards small owls build their nests. Similar
termite structures, of a dark-brown colour, and a round form, are
attached to the thick branches of the trees, and you will scarcely
meet with a single specimen of the tall candelabra-formed cactuses
(_Cerei_), so common on those high grass-plains, that is not loaded
with their weight.
In spite of their working in the dark, in spite of their subterranean
tunnels, their strongholds, and the fecundity of their queens, the
termites, even when their swarms do not expose themselves to the
dangers already mentioned, are subject to the attacks of innumerable
foes--ant-eaters, birds, and a whole host of insects--that do man no
little service by keeping them within bounds.
One of their most ferocious enemies is a species of black ant, which,
on the principle of setting one thief to catch another, is used by
the negroes of Mauritius for their destruction. When they perceive
that the covered ways of the termites are approaching a building, they
drop a train of syrup as far as the nearest encampment of the hostile
army. Some of the black ants, attracted by the smell and taste of
their favourite food, follow its traces and soon find out the termite
habitations. Immediately part of them return to announce the welcome
intelligence, and after a few hours a black army, in endless columns,
is seen to advance against the white-ant stronghold. With irresistible
fury (for the poor termites are no match for their poisonous sting and
mighty mandibles) they rush into the galleries, and only retreat after
the extirpation of the colony. Mr. Baxter (‘Eight Years’ Wanderings in
Ceylon’) once saw an army of black ants returning from one of these
expeditions. Each little warrior bore a slaughtered termite in his
mandibles, rejoicing no doubt in the prospect of a quiet dinner-party
at home. Even man is a great consumer of termites, and they are
esteemed a delicacy by the natives, both in the old and in the new
world.
In some parts of the East Indies the people have an ingenious way of
emptying a termite-hill, by making two holes in it, one to the windward
and the other to the leeward, placing at the latter opening a pot
rubbed with an aromatic herb to receive the insects, when driven out of
their nest by the smoke of a fire made at the former breach. In South
Africa the general way of catching them is to dig into the ant-hill,
and when the builders come forth to repair the damage, to brush them
off quickly into the vessel, as the ant-eater does into his mouth. They
are then parched in iron pots over a gentle fire, stirring them about
as is done in roasting coffee, and eaten by handfuls, without sauce
or any other addition, as we do comfits. According to Smeathman, they
resemble in taste sugared cream, or sweet almond paste, and are, at the
same time, so nutritious that the Hindoos use them as a restorative for
debilitated patients.
While most termites live and work entirely under covered galleries, the
marching white ant (_T. viarum_) exposes itself to the day. Smeathman,
on one occasion, while passing through a dense forest, suddenly heard a
loud hiss like that of a serpent; another followed, and struck him with
alarm; but a moment’s reflection led him to conclude that these sounds
proceeded from white ants, although he could not see any of their huts
around. On following this noise, however, he was struck with surprise
and pleasure at perceiving an army of these creatures emerging from
a hole in the ground, and marching with the utmost swiftness. Having
proceeded about a yard, this immense host divided into two columns,
chiefly composed of labourers, about fifteen abreast, following each
other in close order, and going straight forward. Here and there was
seen a soldier, carrying his vast head with apparent difficulty, at a
distance of a foot or two from the columns; many other soldiers were to
be seen, standing still or passing about, as if upon the look-out lest
some enemy should suddenly surprise their unwarlike comrades. But the
most extraordinary and amusing part of the scene was exhibited by some
other soldiers, who having mounted some plants, ten or fifteen inches
from the ground, hung over the army marching below, and by striking
their jaws upon the leaves at certain intervals, produced the noise
above mentioned; to this signal the whole army immediately returned a
hiss and increased their pace. The soldiers at these signal-stations
sat quite still during these intervals of silence, except now and
then making a slight turn of the head, and seemed as solicitous to
keep their posts as regular sentinels. After marching separately for
twelve or fifteen paces, the two columns of this army again united,
and then descended into the earth by two or three holes. Mr. Smeathman
watched them for more than an hour, without perceiving their numbers to
increase or diminish. Both the labourers and soldiers of this species
are furnished with eyes.
One of the many unsolved mysteries of termite life is whence they
derive the large supplies of moisture with which they not only temper
the clay for the construction of their long covered ways above ground,
but keep their passages uniformly damp and cool below the surface.
Yet their habits in this particular are unvarying, in the seasons
of drought as well as after rain; in the most arid positions; in
situations inaccessible to drainage from above, and cut off by rocks
and impervious strata from springs from below. Struck with this
wonderful phenomenon, Dr. Livingstone raises the question whether the
termites may not possess the power of combining the oxygen or hydrogen
of their vegetable food by vital force, so as to form water; and indeed
it is highly probable that they are endowed with some such faculty,
which, however wonderful, would still be far less astonishing than the
miracles of their architectural instinct.
After having described the miseries which the tropical insects inflict
upon man--how they suck his blood, destroy his rest, exterminate
his cattle, devour the fruits of his fields and orchards, ransack his
chests and wardrobes, feast on his provisions, and plague and worry him
wherever they can--it is but justice to mention their services.
Among the insects which are of _direct_ use to us, the silk-worm
(_Bombyx mori_) is by far the most important. Originally a native of
tropical or sub-tropical China, where the art of making use of its
filaments seems to have been discovered at a very early period, it is
now reared in countless numbers far and wide over the western world,
so as to form a most important feature in the industrial resources
of Europe. Thousands of skilful workmen are employed in spinning and
weaving its lustrous threads, and thousands upon thousands, enjoying
the fruits of their labours, now clothe themselves, at a moderate
price, in silken tissues which but a few centuries back were the
exclusive luxury of the richest and noblest of the land.
Besides the silk-worm, we find many other moths in the tropical
zone whose cocoons might advantageously be spun, and only require
to be better known to become considerable articles of commerce. The
tusseh-worm (_Bombyx mylitta_) of Hindostan, which lives upon the
leaves of the Rhamnus jujuba furnishes a dark-coloured, coarse, but
durable silk; while the Arandi (_B. cynthia_), which feeds upon the
foliage of the castor-oil plant (_Ricinus communis_), spins remarkably
soft threads, which serve the Hindoos to weave tissues of uncommon
strength.
In America, there are also many indigenous moths whose filaments might
be rendered serviceable to man, and which seem destined to great future
importance, when trade, quitting her usual routine, shall have learnt
to pry more closely into the resources of Nature.
While the Cocci, or plant bugs, are in our country deservedly detested
as a nuisance, destroying the beauty of many of our garden plants by
their blighting presence, two tropical members of the family, as if to
make up for the misdeeds of their relations, furnish us--the one with
the most splendid of all scarlet dyes, and the other with gumlac, a
substance of hardly inferior value.
The English gardener spares no trouble to protect his hot- and
greenhouse plants from the invasion of the _Coccus hesperidum_; but
the Mexican _haciendero_ purposely lays out his Nopal plantations
that they may be preyed upon by the _Coccus cacti_, and rejoices when
he sees the leaves of his opuntias thickly strewn with this valuable
parasite. The female, who from her form and habits might not unaptly be
called the tortoise of the insect world, is much larger than the winged
male, and of a dark-brown colour, with two light spots on the back,
covered with a white powder. She uses her little legs only during her
first youth, but soon she sucks herself fast, and henceforward remains
immovably attached to the spot she has chosen, while her mate continues
to lead a wandering life. While thus fixed like an oyster, she swells
or grows to such a size that she looks more like a seed or berry than
an insect; and her legs, antennæ, and proboscis, concealed by the
expanding body, can hardly be distinguished by the naked eye. Great
care is taken to kill the insects before the young escape from the
eggs, as they have then the greatest weight, and are most impregnated
with colouring matter. They are detached by a blunt knife dipped in
boiling water to kill them, and then dried in the sun, when they have
the appearance of small, dry, shrivelled berries, of a deep-brown
purple or mulberry colour, with a white matter between the wrinkles.
The collecting takes place three times a year in the plantations, where
the insect, improved by human care, is nearly twice as large as the
wild coccus, which in Mexico is gathered six times in the same period.
Although the collecting of the cochineal is exceedingly tedious--about
70,000 insects going to a single pound--yet, considering the high
price of the article, its rearing would be very lucrative, if both the
insect and the plant it feeds upon were not liable to the ravages of
many diseases, and the attacks of numerous enemies.
[Illustration: COCHINEAL.]
The conquest of Mexico by Cortez first made the Spaniards acquainted
with cochineal. They soon learnt to value it as one of the most
important products of their new empire, and in order to secure
its monopoly, prohibited, under pain of death, the exportation
of the insect, and of the equally indigenous Nopal, or _Cactus
cochinellifer_, supposing it not to be able to live upon any other
plant. In the year 1677, however, Thierry de Meronville, a Frenchman,
made an effort to deprive them of the exclusive possession of the
treasure they guarded with such jealous care. Under a thousand dangers,
and by means of lavish bribery, he succeeded in transporting some of
the plants, along with their costly parasite, to the French colony of
San Domingo; but, unfortunately, his perseverance did not lead to any
favourable results, and more than a century elapsed after this first
ineffectual attempt before the rearing of cochineal extended beyond its
original limits.
In the year 1827, M. Berthelot, director of the botanical garden at
Orotava, was more fortunate in introducing it into the Canary Islands,
where it thrives so well upon the Opuntia Ficus indica, that Teneriffe
rivals Mexico in its production. At present Cochineal is not only
raised in many other parts of the tropical world, but even in Spain,
near Valencia and Malaga.
The Coccus which produces lac, or gumlac, is a native of India, and
thrives and multiplies best on several species of the fig-tree. A cheap
method having been discovered within the last few years of separating
the colouring matter which it contains from the resinous part, it has
greatly increased in commercial importance.
In the tropical zone we find that not only many birds and several
four-footed animals live chiefly, or even exclusively, on insects,
but that they are even consumed in large quantities, or eaten as
delicacies, by man himself. The nomade of the Sahara and the South
African bushman hail the appearance of locust swarms as a season of
plenty and good living, and ants’ eggs eke out the meagre bill of fare
of the wild Indians on the banks of the Orinoco.
Several of the large African caterpillars are edible, and considered
as a great delicacy by the natives. On the leaves of the Mopané tree,
in the Bushman country, the small larvæ of a winged insect, a species
of Psylla, appear covered over with a sweet gummy substance, which is
collected by the people in great quantities, and used as food. Another
species in New Holland, found on the leaves of the Eucalyptus, emits a
similar secretion, which, along with its insect originator, is scraped
off the leaves and eaten by the aborigines as a saccharine dainty.
The chirping _Cicadæ_, or frog-hoppers, which Aristotle mentions as
delicious food, are still in high repute among the American Indians;
and the Chinese, who allow nothing edible to go to waste, after
unravelling the cocoon of the silkworm, make a dish of the pupæ, which
the Europeans reject with scorn.
The Goliath beetles of the coast of Guinea are roasted and eaten by the
natives, who doubtless, like many other savages, not knowing the value
of that which they are eating, often make a _bonne bouche_ of what an
entomologist would most eagerly desire to preserve.
Several of the more brilliant tropical beetles are made use of as
ornaments, not only by the savage tribes, but among nations which are
able to command the costliest gems of the East. The golden elytra of
the Sternocera chrysis and Sternocera sternicornis serve to enrich
the embroidery of the Indian zenana, while the joints of the legs are
strung on silken threads, and form bracelets of singular brilliancy.
The ladies in Brazil wear necklaces composed of the azure green and
golden wings of lustrous Chrysomelidæ and Curculionidæ, particularly of
the Diamond beetle (_Entimus nobilis_); and in Jamaica, the elytra of
the Buprestis gigas are set in ear-rings, whose gold-green brilliancy
rivals the rare and costly Chrysopras in beauty.
[Illustration: DIAMOND BEETLE.]
[Illustration: BUPRESTIS GIGAS.]
[Illustration: MALAY PIRATES.]