most fierce and implacable little animals in the world, they are in this
state changed into an innocent helpless insect, incapable of making the
least resistance to the smallest ant. The ants are to be seen on every
side in infinite numbers, of various species and sizes, dragging these
annual victims to their different nests. Some are however so fortunate
as to escape, and be discovered by the labouring insects that are
continually running about the surface of the ground under their covered
galleries, the little industrious creatures immediately inclose them in
a small chamber of clay, suitable to their size, into which at first
they leave but one small entrance, only large enough for themselves and
the soldiers to go in and out, but necessity obliges them to make more
entrances. The voluntary subjects charge themselves with the task of
providing for the offspring of their sovereigns, as well as to work and
to fight for them, until they shall have raised a progeny capable at
least of dividing the task with them.
The business of propagation soon commences; and the labourers having
constructed a small wooden nursery, hereafter to be described, carry the
eggs and lodge them there as fast as they can obtain them from the
queen.
About this time a most extraordinary change begins to take place in the
queen, to which we know nothing similar, except in the pulex penetrans
of Linnæus, the jigger of the West-Indies, and in the different species
of coccus cochineal. The abdomen of this female begins gradually to
extend and enlarge to such an enormous size, that an old queen will have
it increased so as to be fifteen hundred or two thousand times the bulk
of the rest of her body, and twenty or thirty thousand times the bulk of
a labourer; the skin between the segments of the abdomen extends in
every direction, and at last the segments are removed to half an inch
distance from each other, though at first the length of the whole
abdomen was not above half an inch. They preserve their dark-brown
colour, and the upper part of the abdomen is marked with a regular
series of brown bars, from the thorax to the posterior part of the
abdomen, while the intervals between them are covered with a thin,
delicate, transparent skin, and appear of a fine cream colour, a little
shaded by the dark colour of the intestines and watery fluid seen here
and there beneath. It is supposed that the animal is upwards of two
years old when the abdomen is increased to three inches in length: they
have sometimes been found of near twice that size. The abdomen is then
of an irregular oblong shape, being contracted by the muscles of every
segment, and is become one vast matrix full of eggs, which make long
circumvolutions through an innumerable quantity of very minute vessels,
that circulate round the inside in a serpentine manner, which would
exercise the ingenuity of a skilful anatomist to dissect and develope.
This singular matrix is not more remarkable for its amazing extension
and size, than for its peristaltic motion, which resembles the
undulation of waves, and continues incessantly without any apparent
effort of the animal; so that one part or other is alternately rising
and sinking in perpetual succession. The matrix seems never at rest, but
to be always protruding eggs to the amount, in old queens, of sixty in
a minute, or eighty thousand and upwards in one day of twenty-four
hours.
These eggs are instantly taken from her body by her attendants, and
carried to the nurseries, which in a great nest may some of them be four
or five feet distant in a straight line, and consequently much farther
by their winding galleries. Here the young, when they are hatched, are
attended and provided with every thing necessary, until they are able to
shift for themselves, and take their share of the labours of the
community.
The termes bellicosus being the largest species, is most remarkable, and
best known on the coast of Africa. It erects immense buildings of
well-tempered clay or earth, which are contrived and finished with such
art and ingenuity, that we are at a loss to say whether they are most to
be admired on that account, or for their enormous magnitude and
solidity. The reason that the larger termites have been most remarked is
obvious; they not only build larger and more curious nests, but are also
more numerous and do infinitely more mischief to mankind.[99]
[99] It may appear surprizing, that a Being perfectly good should have
created animals which seem to serve no other end but to spread
destruction and desolation wherever they go. But let us be cautious in
suspecting any imperfection in the Father of the universe: what, on a
superficial view may seem only productive of mischief, will upon
mature deliberation be found worthy of that wisdom which pervades
every part of the creation. Many poisons prove valuable medicines;
storms are beneficial; and diseases often preserve life, and are
conducive to its future enjoyments. The termites, it must be allowed,
are frequently pernicious to mankind, but they are also very useful,
and even necessary; one valuable purpose which they serve, is, to
destroy decayed trees and other substances, which, if left on the
surface of the ground in hot climates, would in a short time pollute
the air. In this respect, they resemble very much the common flies,
which are regarded by the generality of mankind as noxious, and at
best, as useless beings in the creation; but this is certainly for
want of due consideration. There are not probably in all nature
animals of more importance; and it would not be difficult to prove,
that we should feel the want of one or two species of large quadrupeds
much less than of one or two species of these despicable looking
insects. Nothing is more disagreeable or more pestiferous than putrid
substances; and it is apparent to all who have made the observation,
that these little insects contribute more to the quick dissolution and
dispersion of putrescent matter than any other. They are so necessary
in all hot climates, that even in the open fields a dead animal or
small putrid substance cannot be laid on the ground two minutes,
before it will be covered with flies and their maggots, which
instantly entering, quickly devour one part, and, perforating the rest
in various directions, expose the whole to be much sooner dissipated
by the elements. Thus it is with the termites; the rapid vegetation in
hot climates, of which no idea can be formed by any thing to be seen
in this, is equalled by as great a degree of destruction from natural
as well as accidental causes. When trees and even woods are in part
destroyed by tornados or fire, it is wonderful to observe how many
agents are employed in hastening the total dissolution of the rest; in
this business none are so expert or so expeditious and effectual as
the termites, who in a few weeks destroy and carry away the bodies of
large trees without leaving a particle behind; thus clearing the place
for other vegetables, which soon fill up every vacancy. See Encycl.
Brit. art. Termes. EDIT.
The nests of this species are so numerous all over the island of
Bananas, and the adjacent continent of Africa, that it is scarcely
possible to stand upon any open place, such as a rice plantation, or
other clear spot, where one of these buildings is not to be seen almost
close to each other. In some parts near Senegal, as mentioned by M.
Adanson, their number, magnitude, and closeness of situation, make them
appear like the villages of the natives. These buildings are usually
termed hills, by the inhabitants as well as strangers, from their
outward appearance, which is that of little hills more or less conical,
generally very much in the form of sugar-loaves, and about ten or twelve
feet in perpendicular height above the common surface of the ground.
These hills continue quite bare until they are six or eight feet high;
but, in time, the dead barren clay of which they are composed becomes
fertilized by the genial power of the elements in these prolific
climates, and the addition of vegetable salts and other matters brought
by the wind; and in the second or third year the hillock, if not
overshaded by trees, becomes like the rest of the earth, almost covered
with grass and other plants; and in the dry season, when the herbage is
burnt up by the rays of the sun, it is not much unlike a very large
hay-cock.
Every one of these buildings consists of two distinct parts, the
exterior and interior. The exterior cover is one large clay shell, in
the form of a dome, capacious and strong enough to inclose and shelter
the interior building from the vicissitudes of the weather, and the
inhabitants from the attacks of natural or accidental enemies. The
external cover is always, therefore, much stronger than the interior
building, which is the habitable part, divided with wonderful regularity
and contrivance into an amazing number of apartments for the residence
of the king and queen, for the nursing of their numerous progeny, and
for magazines, which are always found well filled with stores and
provisions.
These hills make their first appearance above ground by a little turret
or two in the shape of sugar-loaves, which are run a foot high or more;
soon after, at some little distance, while the former are increasing in
height and size, they rise others, and so go on increasing the number,
and widening them at the base, till their works below are covered with
these turrets, which the insects always raise highest and largest
towards the middle of the hill, and by filling up the intervals between
each turret, collect them as it were into one dome. They are not very
curious or exact about these turrets, except in making them very solid
and strong; and when, by the junction of them, the dome is completed,
for which purpose the turrets serve as scaffolds, they take away the
middle ones entirely, except the tops, which joined together make the
crown of the cupola, and apply the clay to the building of the works
within, or to erecting fresh turrets for the purpose of raising the
hillock still higher; so that no doubt some part of the clay is used
several times, like the boards and posts of a mason’s scaffold.
The royal chamber, which, on account of its being adapted for, and
occupied by the king and queen, appears to be in the opinion of this
little people, of the most consequence, is always situated as near the
center of the interior building as possible, and generally about the
height of the common surface of the ground, at a pace or two from the
hillock; it is always nearly in the shape of half an egg or an obtuse
oval within, and may be supposed to represent a long oven. In the infant
state of the colony, it is not above an inch, or thereabouts, in length;
but in time will be increased to six or eight inches or more in the
clear, being always in proportion to the size of the queen, who,
increasing in bulk as in age, at length requires a chamber of such
dimensions. The floor is horizontal, sometimes an inch thick and upward
of solid clay; the roof also, which is one solid and well-turned oval
arch, is generally of about the same solidity, but in some places it is
not a quarter of an inch thick; this is on the sides where it joins the
floor, and where the doors or entrances are made. These entrances will
not admit any animal larger than the soldiers or labourers; so that the
king, and the queen, who is when full grown a thousand times the weight
of a king, can never possibly go out. The royal chamber, if in a large
hillock, is surrounded by an innumerable quantity of others, of
different sizes, shapes, and dimensions; but all of them arched,
sometimes of a circular, sometimes of an elliptical form. These chambers
either open into each other, or have communicating passages, and being
always empty, are evidently made for the soldiers and attendants; of
whom, it will soon appear, great numbers are necessary, and of course
always in waiting.
These apartments are joined by the magazines and nurseries; the former
are chambers of clay, and are always well filled with provisions, which
to the naked eye seem to consist of the raspings of wood and plants,
which the termites destroy, but are found by the microscope to be
chiefly composed of the gums or inspissated juices of plants, thrown
together in little masses, some of which are finer than others, and
resemble the sugar about preserved fruits; others are like drops of gum.
The magazines are intermixed with the nurseries, buildings totally
different from the rest of the apartments, being composed entirely of
wooden materials, seemingly joined together with gums. They are called
nurseries because they are invariably occupied by the eggs and young
ones, which appear at first in the shape of labourers, but as white as
snow. These buildings are exceedingly compact, and divided into many
very small irregular-shaped chambers, placed all round the royal
apartments, and as near as possible to them.
When the nest is in the infant state, the nurseries are close to the
royal chamber; but as in process of time the queen increases in size, it
is necessary to enlarge the chamber for her accommodation; and as she
then lays a greater number of eggs, and requires a more numerous train
of attendants, so it is necessary to enlarge and increase the number of
the adjacent apartments; for which purpose, the small nurseries which
are first built, are taken to pieces, rebuilt a little further off, a
size larger, and the number of them increased at the same time. Thus
they continually enlarge their apartments, pull down, repair, or
rebuild, according to their wants, with a degree of sagacity,
regularity, and foresight, not even imitated by any other kind of
animals or insects. The nurseries are inclosed in chambers of clay, like
those which contain the provisions, but much more extensive. In the
early state of the nest they are not larger than an hazel nut, but in
great hills are often as large as a child’s head of a year old.
The royal chamber is situated nearly on a level with the surface of the
ground, at an equal distance from all the sides of the building, and
directly under the apex of the hill. It is, on all sides, both above and
below, surrounded by what may be called the royal apartments, which have
only labourers and soldiers in them, and can be intended for no other
purpose than for these to wait in, either to guard or serve their common
father and mother, on whose safety depends the happiness, and, according
to the account of the negroes, even the existence of the whole
community.
These apartments form an intricate labyrinth, which extends a foot or
more in diameter from the royal chamber on every side. Here the
nurseries and magazines of provisions begin, and being separated by
small empty chambers and galleries, which go round them, or communicate
from one to the other, are continued on all sides to the outward shell,
and reach up within it two-thirds or three-fourths of its height, having
an open area in the middle under the dome, resembling the nave of an old
cathedral. This area is surrounded by large gothic arches, which are
sometimes two or three feet high next the front of the area, but
diminish very rapidly as they recede from thence, like the arches of
aisles in perspective, and are soon lost among the innumerable chambers
and nurseries behind them. All these chambers, and the passages leading
to and from them, being arched, contribute to support one another; and
while the interior large arches prevent their falling into the center,
and keep the area open, the exterior building supports them on the
outside.
The interior building, or assemblage of nurseries, chambers, &c. has a
flattish top or roof without any perforation; by this contrivance, if
any water should penetrate the external dome, the apartments below are
preserved from injury. It is never exactly flat and uniform, because
they are always adding to it by building more chambers and nurseries: so
that the divisions or columns between the future arched apartments
resemble the pinnacles upon the fronts of some old buildings, and demand
particular notice, as affording one proof that for the most part the
insects project their arches, and do not make them by excavation. The
area is likewise water-proof, and contrived so as to let the water off,
if it should get in and run over, by some short way, into the
subterraneous passages, which run under the lowest apartments in the
hill in various directions, and are of an astonishing size, being wider
than the bore of a great cannon. There is an account of one that was
measured, which was perfectly cylindrical, and thirteen inches in
diameter.
These subterraneous passages or galleries are lined very thick with the
same kind of clay of which the hill is composed, and ascend the inside
of the outward shell in a spiral manner; winding round the whole
building up to the top, they intersect each other at different heights,
opening either immediately into the dome in various places, and into the
interior building, the new turrets, &c. or communicating thereto by
other galleries of different bores or diameters, either circular or
oval.
From every part of these large galleries are various small pipes or
galleries, leading to different parts of the building; under ground
there are a great many which lead downward, by sloping descents three
and four feet perpendicular among the gravel, from whence the labouring
termites cull the finer parts, which being worked up in their mouths to
the consistence of mortar, becomes that solid clay or stone, of which
their hills and all their buildings, except the nurseries, are composed.
Other galleries again ascend and lead out horizontally on every side,
and are carried under ground near to the surface, a vast distance.
There is a kind of necessity for the galleries under the hills being
thus large, as they are the great thoroughfares for all the labourers
and soldiers going forth or returning upon any business whatever,
whether fetching clay, wood, water, or provisions; and they are
certainly well calculated for the purposes to which they are applied, by
the spiral slope which is given them.
Those species which build either the roofed turrets, or the nests in the
trees, seem in most instances to have a strong resemblance to the
preceding, both in their form and œconomy, going through the same
changes from the egg to the winged state. The queens also increase to a
great size when compared with the labourers, but very short of those
queens before described. The largest are from about an inch to an inch
and an half long, and not much thicker than a common quill. There is the
same kind of peristaltic motion in the abdomen, but in a much smaller
degree; and as the animal is incapable of moving from her place, the
eggs, no doubt are carried to the different cells by the labourers, and
reared with a care similar to that which is practised in the larger
nests.
It is remarkable of all these different species, that the working and
the fighting insects never expose themselves to the open air, but either
travel under ground, or within such trees and substances as they
destroy; except, indeed, when they cannot proceed by their latent
passages, and find it convenient or necessary to search for plunder
above ground: in that case they make pipes of that material with which
they build their nests. The larger sort use the red clay; the turret
builders use the black clay; and those which build in the trees employ
the same ligneous substance of which their nests are composed.
The termites, except their heads, are exceedingly soft, and covered with
a very thin and delicate skin; being blind, they are no match on open
ground for the ants, who can see, and are all of them covered with a
strong horny shell not easily pierced, and are of dispositions bold,
active, and rapacious.
Whenever the termites are dislodged from their covered ways, the various
species of formicæ or ants, who probably are as numerous above ground,
as the latter are in their subterraneous passages, instantly seize and
drag them away to their nests, to feed the young brood. The termites
are, therefore, exceedingly solicitous about the preserving their
covered ways in good repair; and if you demolish one of them for a few
inches in length, it is wonderful how soon they re-build it. At first in
their hurry they get into the open part an inch or two, but stop so
suddenly, that it is very apparent they are surprized; for, though some
run straight on, and get under the arch as speedily as possible in the
further part, most of them run as fast back, and very few will venture
through that part of the track which is left uncovered. In a few minutes
you will perceive them re-building the arch, and by the next morning
they will have restored their gallery for three or four yards in length,
if so much has been ruined; and upon opening it again, will be found as
numerous as ever under it, passing both ways. If you continue to destroy
it several times, they will at length seem to give up the point, and
build another in a different direction; but, if the old one should lead
to some favourite plunder, in a few days will re-build it again, and,
unless you destroy their nest, never totally abandon their, gallery.
OF THE HABITATIONS OF CATERPILLARS.
Though the view which has already been given of the various proceedings
of insects in forming their habitations, has extended to some length, I
cannot with propriety omit noticing the wonderful art and industry
which is manifested in these respects by the caterpillar; and more
particularly so, as from the larva state the foundation of all our
present knowledge of the natural history of insects has been obtained.
Some species of caterpillars form a kind of hammock, in which they eat
and go through their various changes; while others erect a silken tent,
under which they live until they have consumed the surrounding herbs.
They then leave their abodes, and pitch their tents in a more fruitful
spot.
Many associate together all their lives; these proceed from the same
moth, who deposited her eggs near each other, or rather laid them in a
heap, forming as it were a kind of nest. They are generally hatched on
the same day, and, living together, constitute a new species of
republic, in which all are brethren. They often amount to near six
hundred in a family, though they are frequently to be found with only
about two hundred. Of these social caterpillars there are some species
which not only continue with the society while they are in a larva
state, but even place their pupæ close together. There are other kinds
who associate only for a short period.
Among the vast variety of insects which inhabit the oak, there is a
species of caterpillar which live separate till they arrive at a certain
age; they then assemble together, and do not quit each other till they
attain their perfect state. As the number thus assembled is
considerable, the nest is also very large. They remain in-doors during
the day, not leaving their habitation till sun-set. When they go out,
one of the body precedes the rest as a chief, whom they regularly
follow; when the leader stops, the rest do the same, and wait till it
goes on again, before they recommence their march. The first file
generally consists of a single caterpillar, which is succeeded by a
double file; these, by three in a row, which are then followed by files
of five, and so on. They keep exceeding close to each other, not leaving
any interval either between the ranks, or those in each rank; all of
them following their captain in every direction, whether straight or
crooked. After they have taken their repast, which is done on the march,
they return to their nest in the same order in which they set out.
This mode is followed till they are full grown, when each forms a cone,
in which it is changed into a chrysalis. M. Bonnet has shewn, that
though these caterpillars proceed often very far from their nest, it is
by no means difficult for them to get back again, because they spin over
all the places in their rout. The first leads the way, the second
follows spinning, the third spins after the first and second, and so on
with the rest. All these threads form by degrees a small shining track,
a little path; and all these paths meet at the nest. To be fully
convinced of the use of these threads, let any one but break the
continuation of them in some particular part, and he will see the little
caterpillars turn back, as if they were at a loss, till one more daring
than the rest restores the communication by spinning new threads.