generation, their peculiar habits, the metamorphoses they undergo;
their manner of life under each successive form; the stratagems for
the attack of their enemies, and the skill with which they construct
their habitation: but that of insects which form numerous societies,
is not confined to some remarkable proceedings, to some peculiar
talent: it offers new relations, which arise from common interest;
from the equality or superiority of rank; from the part which each
member supports in the society;--and all these relations suppose a
connexion between the different individuals of which it consists,
that can scarcely exist but by the intervention of language: for such
may be called every mode of expressing their wishes, their wants,
and even their ideas, if that name may be given to the impulses of
instinct. It would be difficult to explain in any other way that
concurrence of all wills to one end, and that species of harmony
which the whole of their institution exhibits."
The great end of the societies of insects being the rapid
multiplication of the species, Providence has employed extraordinary
means to secure the fulfilment of this object, by creating a
particular order of individuals in each society, which, freed from
sexual pursuits, may give themselves wholly to labour, and thus
absolve the females from every employment but that of furnishing
the society from time to time with a sufficient supply of eggs to
keep up the population to its proper standard. In the case of the
_Termites_, the office of working for the society, as these insects
belong to an order whose metamorphosis is _semi-complete_, devolves
upon the larvæ; the neuters, unless these should prove to be the
larvæ of males, being the soldiers of the community.
From this circumstance perfect societies may be divided into two
classes; the first including those whose workers are _larvæ_, and the
second those whose workers are _neuters_[37]. The white ants belong to
the former of these classes, and the social _Hymenoptera_ to the latter.
Before I begin with the history of the societies of white ants, I
must notice a remark that has been made applying to societies in
general--that numbers are essential to the full development of the
instinct of social animals. This has been observed by Bonnet with
respect to the beaver[38]; by Reaumur of the hive-bee; and by M. P.
Huber of the humble-bee[39]. Amongst hymenopterous social insects,
however, the observation seems not universally applicable, but only
under particular circumstances; for in incipient societies of ants,
humble-bees, and wasps, one female lays the foundations of them at
first by herself; and the first brood of neuters that is hatched is
very small.
* * * * *
I have on a former occasion given you some account of the
devastation produced by the white ants, or _Termites_, the species of
which constitute the first class of perfect societies[40]; I shall
now relate to you some further particulars of their history, which
will, I hope, give you a better opinion of them.
The majority of these animals are natives of tropical countries,
though two species are indigenous to Europe; one of which, thought to
have been imported, is come so near to us as Bourdeaux. The fullest
account hitherto given of their history is that of Mr. Smeathman, in
the _Philosophical Transactions_ for 1781; which, since it has in
many particulars been confirmed by the observations of succeeding
naturalists, though in some things he was evidently mistaken, I shall
abridge for you, correcting him where he appears to be in error, and
adding from Latreille, and the MS. of a French naturalist resident
on the spot, kindly furnished by Professor Hooker, what they have
observed with respect to those of Bourdeaux and Ceylon. The white
ants, though they belong to the _Neuroptera_ order, borrow their
instinct from the hymenopterous social tribes, and in conjunction
with the ants (_Formica_) connect the two orders. Their societies
consist of five different descriptions of individuals--workers or
larvæ--nymphs or pupæ--neuters or soldiers--males and females.
1. The _workers_ or larvæ, answering to the hymenopterous neuters,
are the most numerous and at the same time most active part of the
community; upon whom devolves the office of erecting and repairing
the buildings, collecting provisions, attending upon the female,
conveying the eggs when laid to what Smeathman calls the nurseries,
and feeding the young larvæ till they are old enough to take care
of themselves. They are distinguished from the soldiers by their
diminutive size, by their round heads and shorter mandibles.
2. The _nymphs_ or pupæ. These were not noticed by Smeathman, who
mistook the neuters for them:--they differ in nothing from the larvæ,
and probably are equally active, except that they have rudiments of
wings, or rather the wings folded up in cases (_Pterothecæ_). They were
first observed by Latreille; nor did they escape the author of the MS.
above alluded to, who mistook them for a different kind of larvæ.
3. The _neuters_, erroneously called by Smeathman pupæ. These are
much less numerous than the workers, bearing the proportion of one
to one hundred, and exceeding them greatly in bulk. They are also
distinguishable by their long and large head, armed with very long
subulate mandibles. Their office is that of sentinels; and when the
nest is attacked, to them is committed the task of defending it.
These neuters are quite unlike those in the _Hymenoptera_ perfect
societies, which seem to be a kind of abortive females, and there is
nothing analogous to them in any other department of Entomology.
4. and 5. _Males_ and _females_, or the insects arrived at their state
of perfection, and capable of continuing the species. There is only
one of each in every separate society; they are exempted from all
participation in the labours and employments occupying the rest of
the community, that they may be wholly devoted to the furnishing of
constant accessions to the population of the colony. Though at their
first disclosure from the pupa they have four wings, like the female
ants they soon cast them; but they may then be distinguished from the
blind larvæ, pupæ, and neuters, by their large and prominent eyes[41].
The first establishment of a colony of Termites takes place in the
following manner. In the evening, soon after the first tornado, which
at the latter end of the dry season proclaims the approach of the
ensuing rains, these animals, having attained to their perfect state,
in which they are furnished and adorned with two pair of wings, emerge
from their clay-built citadels by myriads and myriads to seek their
fortune. Borne on these ample wings, and carried by the wind, they
fill the air, entering the houses, extinguishing the lights, and even
sometimes being driven on board the ships that are not far from the
shore. The next morning they are discovered covering the surface of the
earth and waters: deprived of the wings which before enabled them to
avoid their numerous enemies, and which are only calculated to carry
them a few hours, and looking like large maggots; from the most active,
industrious, and rapacious, they are now become the most helpless and
cowardly beings in nature, and the prey of innumerable enemies, to
the smallest of which they make not the least resistance. Insects,
especially ants, which are always on the hunt for them, leaving no
place unexplored; birds, reptiles, beasts, and even man himself, look
upon this event as their harvest, and, as you have been told before,
make them their food; so that scarcely a single pair in many millions
get into a place of safety, fulfill the first law of nature, and lay
the foundation of a new community. At this time they are seen running
upon the ground, the male after the female, and sometimes two chasing
one, and contending with great eagerness, regardless of the innumerable
dangers that surround them, who shall win the prize.
The workers, who are continually prowling about in their covered ways,
occasionally meet with one of these pairs, and, being impelled by their
instinct, pay them homage, and they are elected as it were to be king
and queen, or rather father and mother, of a new colony[42]: all that
are not so fortunate, inevitably perish; and, considering the infinite
host of their enemies, probably in the course of the following day.
The workers, as soon as this election takes place, begin to inclose
their new rulers in a small chamber of clay, before described[43],
suited to their size, the entrances to which are only large enough to
admit themselves and the neuters, but much too small for the royal
pair to pass through;--so that their state of royalty is a state of
confinement, and so continues during the remainder of their existence.
The impregnation of the female is supposed to take place after this
confinement, and she soon begins to furnish the infant colony with new
inhabitants. The care of feeding her and her male companion devolves
upon the industrious larvæ, who supply them both with every thing
that they want. As she increases in dimensions, they keep enlarging
the cell in which she is detained. When the business of oviposition
commences, they take the eggs from the female, and deposit them in the
nurseries[44]. Her abdomen now begins gradually to extend, till in
process of time it is enlarged to 1500 or 2000 times the size of the
rest of her body, and her bulk equals that of 20,000 or 30,000 workers.
This part, often more than three inches in length, is now a vast matrix
of eggs, which make long circumvolutions through numberless slender
serpentine vessels:--it is also remarkable for its peristaltic motion,
(in this resembling the female ant[45],) which, like the undulations of
water, produces a perpetual and successive rise and fall over the whole
surface of the abdomen, and occasions a constant extrusion of the eggs,
amounting sometimes in old females to sixty in a minute, or eighty
thousand and upwards in twenty-four hours[46]. As these females live
two years in their perfect state, how astonishing must be the number
produced in that time!
This incessant extrusion of eggs must call for the attention of a
large number of the workers in the royal chamber (and indeed it is
always full of them), to take them as they come forth and carry them
to the nurseries; in which, when hatched, they are provided with
food, and receive every necessary attention till they are able to
shift for themselves.--One remarkable circumstance attends these
nurseries--they are always covered with a kind of mould, amongst
which arise numerous globules about the size of a small pin's head.
This is probably a species of _Mucor_; and by Mr. König, who
found them also in nests of an East-Indian species of Termes, is
conjectured to be the food of the larvæ.
The royal cell has besides some soldiers in it, a kind of body guard
to the royal pair that inhabit it; and the surrounding apartments
contain always many both labourers and soldiers in waiting, that they
may successively attend upon and defend the common father and mother,
on whose safety depend the happiness and even existence of the whole
community; and whom these faithful subjects never abandon even in the
last distress.
The manner in which the Termites feed the young brood, before they
commence their active life and are admitted to share in the labours of
the nest, has not, as far as I know, been recorded by any writer: I
shall therefore leave them in their nurseries, and introduce you to the
bustling scene which these creatures exhibit in their first state after
they are become useful. To do this, in vain should I carry you to one
of their nests--you would scarcely see a single one stirring--though,
perhaps, under your feet there would be millions going and returning
by a thousand different ways. Unless I possessed the power of Asmodeus
in _Le Diable Boiteux_, of showing you their houses and covered ways
with their roofs removed, you would return home as wise as you came;
for these little busy creatures are taught by Providence always to work
under cover. If they have to travel over a rock or up a tree, they
vault with a coping of earth the route they mean to pursue, and they
form subterranean paths and tunnels, some of a diameter wider than the
bore of a large cannon, on all sides from their habitation to their
various objects of attack; or which sloping down (for they cannot well
mount a surface quite perpendicular) penetrate to the depth of three
or four feet under their nests into the earth, till they arrive at a
soil proper to be used in the erection of their buildings. Were they,
indeed, to expose themselves, the race would soon be annihilated by
their innumerable enemies. This circumstance has deceived the author
of the MS. account of those in Ceylon, who, speaking of the nests of
these insects in that island, which he describes as twelve feet high,
observes, that "they may be considered as a large city, which contains
a great number of houses, and these houses an infinite number of
cells or apartments:----these cells appear to me to communicate with
each other, but not the houses. I have convinced myself, by bringing
together the broken walls of one of the cavities of the nest or cone,
that it does not communicate with any other, nor _with the exterior_ of
the cone--a very curious circumstance, which I will not undertake to
explain. Other cavities communicate by a very narrow tunnel." By not
looking for subterranean communications, he was probably led into this
error.
You have before heard of their diligence in building. Does any accident
happen to their various structures, or are they dislodged from any
of their covered ways, they are still more active and expeditious in
repairing. Getting out of sight as soon as possible,--and they run as
fast or faster than any insect of their size,--in a single night they
will restore a gallery of three or four yards in length. If, attacking
the nest, you divide it in halves, leaving the royal chamber, and thus
lay open thousands of apartments, all will be shut up with their sheets
of clay by the next morning;--nay, even if the whole be demolished,
provided the king and the queen be left, every interstice between the
ruins, at which either cold or wet can possibly enter, will be covered,
and in a year the building will be raised nearly to its pristine size
and grandeur.
Besides building and repairing, a great deal of their time is
occupied in making necessary alterations in their mansion and its
approaches. The royal presence-chamber, as the female increases in
size, must be gradually enlarged, the nurseries must be removed to a
greater distance, the chambers and exterior of the nest receive daily
accessions to provide for a daily increasing population--and the
direction of their covered ways must often be varied, when the old
stock of provision is exhausted and new discovered.
The collection of provisions for the use of the colony is another
employment, which necessarily calls for incessant attention: these
to the naked eye appear like raspings of wood;--and they are, as
you have seen, great destroyers of timber, whether wrought or
unwrought:--but when examined by the microscope, they are found to
consist chiefly of gums and the inspissated juices of plants, which,
formed into little masses, are stored up in magazines made of clay.
When any one is bold enough to attack their nest and make a breach
in its walls, the labourers, who are incapable of fighting, retire
within, and give place to another description of its inhabitants, whose
office it is to defend the fortress when assailed by enemies:--these,
as observed before, are the neuters or soldiers. If the breach be
made in a slight part of the building, one of these comes out to
reconnoitre; he then retires and gives 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. It is not easy to describe the rage and fury by which these
diminutive heroes seem actuated. 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 every thing they
run against. If the attack proceeds, the bustle and agitation increase
to a ten-fold degree, and their fury is raised to its highest pitch.
Wo to him whose hands or legs they can come at! for they will make
their fanged jaws meet at the very first stroke, drawing as much blood
as will counterpoise their whole body, and never quitting their hold,
even though they are pulled limb from limb. The naked legs of the
Negroes expose them frequently to this injury; and the stockings of the
European are not sufficient to defend him.
On the other hand, if, after the first attack, you get a little
out of the way, giving them no further interruption, supposing the
assailant of their citadel is gone beyond their reach, in less than
half an hour they will retire into the nest; and before they have all
entered, you will see the labourers in motion, hastening in various
directions towards the breach, every one carrying in his mouth a mass
of mortar half as big as his body[47], ready tempered:--this mortar
is made of the finer parts of the gravel, which they probably select
in the subterranean pits or passages before described, which, worked
up to a proper consistence, hardens to the solid substance resembling
stone, of which their nests are constructed. As fast as they come up,
each sticks its burthen upon the breach; and this is done with so
much regularity and dispatch, that although thousands, nay millions,
are employed, they never appear to embarrass or interrupt one
another. By the united labours of such an infinite host of creatures
the wall soon rises and the breach is repaired.
While the labourers are thus employed, almost all the soldiers
have retired quite out of sight, except here and there one, who
saunters about amongst them, but never assists in the work. One in
particular places himself close to the wall which they are building;
and turning himself leisurely on all sides, as if to survey the
proceedings, appears to act the part of an overseer of the works.
Every now and then, at the interval of a minute or two, by lifting
up his head and striking with his forceps upon the wall of the nest,
he makes a particular noise, which is answered by a loud hiss from
all the labourers, and appears to be a signal for dispatch; for,
every time it is heard, they may be seen to redouble their pace, and
apply to their work with increased diligence. Renew the attack, and
this amusing scene will be repeated:--in rush the labourers, all
disappearing in a few seconds, and out march the military as numerous
and vindictive as before.--When all is once more quiet, the busy
labourers reappear, and resume their work, and the soldiers vanish.
Repeat the experiment a hundred times, and the same will always be
the result;--you will never find, be the peril or emergency ever so
great, that one order attempts to fight, or the other to work.
You have seen how solicitous the Termites are to move and work under
cover and concealed from observation; this, however, is not always
the case;--there is a species larger than _T. bellicosus_, whose
proceedings I have been principally describing, which Mr. Smeathman
calls the marching Termes (_Termes Viarum_). He was once passing
through a thick forest, when on a sudden a loud hiss, like that of
serpents, struck him with alarm. The next step produced a repetition
of the sound, which he then recognised to be that of white ants;
yet he was surprised at seeing none of their hills or covered ways.
Following the noise, to his great astonishment and delight he saw an
army of these creatures emerging from a hole in the ground; their
number was prodigious, and they marched with the utmost celerity.
When they had proceeded about a yard they 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,
and looking like an ox in a flock of sheep, who marched on in the
same manner. At the distance of a foot or two from the columns many
other soldiers were to be seen, standing still or pacing about as if
upon the look-out, lest some enemy should suddenly surprise their
unwarlike comrades;--other soldiers, which was the most extraordinary
and amusing part of the scene, having mounted some plants and placed
themselves on the points of their leaves, elevated from ten to
fifteen inches from the ground, hung over the army marching below,
and by striking their forceps upon the leaf, produced at intervals
the noise before mentioned. To this signal the whole army returned a
hiss, and obeyed it by increasing their pace. The soldiers at these
signal-stations sat quite still during the 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. The two
columns of this army united after continuing separate for twelve or
fifteen paces, having in no part been above three yards asunder, and
then descended into the earth by two or three holes. Mr. Smeathman
continued watching them for above an hour, during which time their
numbers appeared neither to increase nor diminish:--the soldiers,
however, who quitted the line of march and acted as sentinels, became
much more numerous before he quitted the spot. The larvæ and neuters
of this species are furnished with eyes.
The societies of _Termes lucifugus_, discovered by Latreille at
Bourdeaux, are very numerous; but instead of erecting artificial
nests, they make their lodgement in the trunks of pines and oaks,
where the branches diverge from the tree. They eat the wood the
nearest the bark, or the alburnum, without attacking the interior,
and bore a vast number of holes and irregular galleries. That part
of the wood appears moist, and is covered with little gelatinous
particles, not unlike gum-arabic. These insects seem to be furnished
with an acid of a very penetrating odour, which perhaps is useful
to them for softening the wood[48]. The soldiers in these societies
are as about one to twenty-five of the labourers[49]. The anonymous
author of the observations on the Termites of Ceylon seems to have
discovered a sentry-box in his nests. "I found," says he, "in a very
small cell in the middle of the solid mass, (a cell about half an
inch in height, and very narrow,) a larva with an enormous head.--Two
of these individuals were in the same cell:--one of the two seemed
placed as sentinel at the entrance of the cell. I amused myself
by forcing the door two or three times;--the sentinel immediately
appeared, and only retreated when the door was on the point to be
stopped up, which was done in three minutes by the labourers."
* * * * *
I hope this account has reconciled you in some degree to the
destructive Termites:--I shall next introduce you to social insects,
concerning most of which you have probably conceived a more
favourable opinion;--I mean those which constitute the second class
of perfect societies, whose workers are not larvæ, but neuters.
These all belong to the _Hymenoptera_ order of Linné:--there are
four kinds of insects in this order, (which you will find as fertile
in the instructors of mankind, as you have seen it to be in our
benefactors,) that, varying considerably from each other in their
proceedings as social animals, separately merit your attention:
namely, ants, wasps and hornets, humble-bees, and the hive-bee. I
begin with the first.