Chapter IV: Bees and Wasps (2)

As soon as the queen has been fertilised, and the services of the drones therefore no longer required, the worker bees fall upon their unfortunate and defenceless brothers to kill them, either by direct stinging or by throwing them out of the hive to perish in the cold. The drones' cells are then torn down, and any remaining drone eggs or pupæ destroyed. Generally all the drones--which may number more than a thousand--are slaughtered in the course of a single day. Evidently the object of this massacre is that of getting rid of useless mouths; but there is a more difficult question as to why these useless mouths ever came into existence. It has been suggested that the enormous disproportion between the present number of males and the single fertile female refers to a time before the social instincts became so complex or consolidated, and when, therefore, bees lived in lesser communities. Probably this is the explanation, although I think we might still have expected that before this period in their evolution had arrived bees might have developed a compensating instinct, either not to allow the queen to lay so many drone eggs, or else to massacre the drones while still in the larval state. But here we must remember that among the wasps the males do work (chiefly domestic work, for which they are fed by their foraging sisters); so it is possible that in the hive-bee the drones were originally useful members of the community, and that they have lost their primitively useful instincts. But whatever the explanation, it is very curious that here, among the animals which are justly regarded as exhibiting the highest perfection of instinct, we meet with perhaps the most flagrant instance in the animal kingdom of instinct unperfected. It is the more remarkable that the drone-killing instinct should not have been better developed in the direction of killing the drones at the most profitable time--namely, in their larval or oval state--from the fact that in many respects it seems to have been advanced to a high degree of discriminative refinement. Thus, to quote Büchner,--

That the massacre of the drones is not performed
entirely from an instinctive impulse, but in full
consciousness of the object to be gained, is proved by
the circumstance that it is carried out the more
completely and mercilessly the more fertile the queen
shows herself to be. But in cases where this fertility
is subject to serious doubt, or when the queen has
been fertilised too late or not at all, and therefore
only lays drones' eggs, or when the queen is barren,
and new queens, to be fertilised later, have to be
brought up from working-bee larvæ, then all or some of
the drones are left alive, in the clear prevision that
their services will be required later. . . . This wise
calculation of consequences is further exemplified in
that sometimes the massacre of the drones takes place
before the time for swarming, as, for instance, when
long-continued unfavourable weather succeeds a
favourable beginning of spring, and makes the bees
anxious for their own welfare. If, however, the
weather breaks, and work again becomes possible, so
that the bees take courage anew, they then bring up
new drones, and prepare them in time for the swarming.
This killing of drones is distinguished from the
regular drone massacre by the fact that the bees then
only kill the developed drones, and leave the drone
larvæ, save when absolute hunger compels their
destruction. Not less can it be regarded as a prudent
calculation of circumstances when the bees of a hive,
brought from our temperate climate to a more southern
country, where the time of collecting lasts longer, do
not kill the drones in August, as usual, but at a
later period, suitable to the new conditions.

But the philosophy of drone-killing is, I think, even more difficult in the case of the wasps than in that of the bees. For, unlike the bees, whose communities live from year to year, the wasps all perish at the end of autumn, with the exception of a very few fertilised females. As this season of universal calamity approaches, the workers destroy all the larval grubs--a proceeding which, in the opinion of some writers, strikingly exemplifies the beneficence of the Deity! Now, it does not appear to me easy to understand how the presence of such an instinct in this case is to be explained. For, on the one hand, the individual females which are destined to live through the winter cannot be conspicuously benefited by this slaughter of grubs; and, on the other hand, the rest of the community is so soon about to perish, that one fails to see of what advantage it can be to it to get rid of the grubs. If the whole human race, with the exception of a few women, were to perish periodically once in a thousand years, the race would profit nothing by destroying, a few months before the end of each millennium, all sick persons, lunatics, and other 'useless mouths.' I have not seen this difficulty with regard to the massacring instinct in wasps mentioned before, and I only mention it now in order to draw attention to the fact that there seems to be a more puzzling problem presented here than in the case of the analogous instinct as exhibited by bees. The only solution which has suggested itself to my mind is the possibility that in earlier times, or in other climates, wasps may have resembled bees in living through the winter, and that the grub-slaying instinct is in them a survival of one which was then, as in the case of the bees now, a clearly beneficial instinct.

For some days before swarming begins, there is a great excitement and buzzing in the hive, the temperature of which rises from 92° to 104°. Scouts having been previously sent out to explore for suitable quarters wherein to plant the new colony, these now act as guides. The swarm leaves the hive with their queen. The bees which remain behind busy themselves in rearing out the pupæ, which soon arriving at maturity, also quit the hive in successive swarms. According to Büchner, 'secondary swarms with young queens send out no scouts, but fly at random through the air. They clearly lack the experience and prudence of the older bees.' And, regarding the behaviour of the scouts sent out by primary swarms, this author says:--

M. de Fravière had the opportunity of observing the
manner in which such an examination is carried on, and
with what prudence and accuracy. He placed an empty
beehive, made in a new style, in front of his house,
so that he could exactly watch from his own window
what went on inside and out without disturbance to
himself or to the bees. A single bee came and examined
the building, flying all round it and touching it. It
then let itself down on the board, and walked
carefully and thoroughly over the interior, touching
it continually with its antennæ so as to subject it on
all sides to a thorough investigation. The result of
its examination must have been satisfactory, for after
it had gone away it returned accompanied by a crowd of
some fifty friends, which now together went through
the same process as their guide. This new trial must
also have had a good result, for soon a whole swarm
came, evidently from a distant spot, and took
possession. Still more remarkable is the behaviour of
the scouts when they take possession of a satisfactory
hive or box for an imminent or approaching swarm.
Although it is not yet inhabited they regard it as
their property, watch it and guard it against stranger
bees or other assailants, and busy themselves
earnestly in the most careful cleansing of it, so far
as this cleansing is impossible to the setter up of
the hive. Such a taking possession sometimes occurs
eight days before the entrance of the swarm.

_Wars._--As with ants, so with bees, the great cause of war is plunder; and facts now well substantiated by numberless observers concerning 'robber-bees' indicate a large measure of intelligence. These aim at lessening their labour in collecting honey by plundering the store of other hives. The robberies may be conducted singly or in concert. When the thieving propensity is developed only in individual cases, the thieves cannot rely on force in plundering a foreign state, and so resort to cautious stealth. 'They show by their whole behaviour--creeping into the hive with careful vigilance--that they are perfectly conscious of their bad conduct; whereas the workers belonging to the hive fly in quickly and openly, and in full consciousness of their right.' If such solitary burglars are successful in obtaining plunder, their bad example leads other members of their own community to imitate them; thus it is that the whole bee-nation may develop marauding habits, and when they do this they act in concert to rob by force. In this case an army of bees precipitates itself upon the foreign hive, a battle ensues, and if successful in overcoming resistance, the invaders first of all search out the queen-bee and put her to death, whereby they disorganise their enemies and plunder the hive with ease. It is observed that when this policy is once successful, the spirit of aggrandisement is encouraged, so that the robber-bees 'find more pleasure in robbery than in their own work, and become at last formidable robber-states.' When an invaded hive is fairly overcome by the invaders killing the queen, the owners of the hive, finding that all is lost, not only abandon further resistance, but very often reverse their policy and join the ranks of their conquerors. They assist in the tearing down of their cells, and in the conveyance of the honey to the hive of their invaders. 'When the assailed hive is emptied, the next ones are attacked, and if no effective resistance is offered, are robbed in similar fashion, so that in this way a whole bee-stand may be gradually destroyed.' Siebold observed the same facts in the case of wasps (_Polistes gallica_). If, however, the battle turns in favour of the defenders, they pursue the flying legions of their enemies to a distance from their home. It sometimes happens that the plundered hive offers no resistance at all, owing to the robbers having visited the same flowers as the robbed, and so probably (having much the same smell) not being recognised as belonging to a different community. The thieves, when they find such to be the case, may become so bold as to stop the bees that are returning to the hive with their loads, of which they deprive them at the entrance of the hive. This is done by a process which one observer, Weygandt,[56] calls 'milking,' and it seems that the milking bee attains the double advantage of securing the honey from the milked one and disarming suspicion of the other bees by contracting its smell and entering the hive loaded, into which it is admitted without opposition to continue its plunder.

Sometimes robber-bees attack their victims in the fields at a distance from the hives. This sort of highway robbery is generally conducted by a gang of four or five robber-bees which set upon a single honest bee, 'hold him by the legs, and pinch him until he unfolds his tongue, which is sucked in succession by his assailants, who then suffer him to depart in peace.'

It is strange that hive-bees of dishonest temperaments seem able to coax or wheedle humble-bees into the voluntary yielding of honey. 'Humble-bees have been known to permit hive-bees to take the whole honey that they have collected, and to go on gathering more, and handing it over, for three weeks, although they refuse to part with it, or seek refuge in flight, when wasps make similar overtures.'[57]

Besides theft and plunder, there are other causes of warfare among bees, which, however, are only apparent in their effects. Thus, for some undiscernible reason, duels are not infrequent, which generally end in the death of one or both combatants. At other times, equally without apparent reason, civil war breaks out in a hive, which is sometimes attended with much slaughter.

_Architecture._--Coming now to the construction of the cells and combs, there is no doubt that here we meet with the most astonishing products of instinct that are presented in the animal kingdom. A great deal has been written on the practical exhibition of high mathematical principles which bees display in constructing their combs in the form that secures the utmost capacity for storage of honey with the smallest expenditure of building material. The shortest and clearest statement of the subject that I have met with is the following, which has been given by Dr. Reid:--

There are only three possible figures of the cells
which can make them all equal and similar, without any
useless interstices. These are the equilateral
triangle, the square, and the regular hexagon.
Mathematicians know that there is not a fourth way
possible in which a plane may be cut into little
spaces that shall be equal, similar, and regular,
without useless spaces. Of the three figures, the
hexagon is the most proper for convenience and
strength. Bees, as if they knew this, make their cells
regular hexagons.

Again, it has been demonstrated that, by making the
bottoms of the cells to consist of three planes
meeting in a point, there is a saving of material and
labour in no way inconsiderable. The bees, as if
acquainted with these principles of solid geometry,
follow them most accurately. It is a curious
mathematical problem, at what precise angle the three
planes which compose the bottom of a cell ought to
meet, in order to make the greatest possible saving,
or the least expense of material and labour. This is
one of the problems which belong to the higher parts
of mathematics. It has accordingly been resolved by
some mathematicians, particularly by the ingenious
Maclaurin, by a fluctionary calculation, which is to
be found in the Transactions of the Royal Society of
London. He has determined precisely the angle
required, and he found, by the most exact mensuration
the subject would admit, that it is the very angle in
which the three planes in the bottom of the cell of a
honeycomb do actually meet.[58]

Marvellous as these facts undoubtedly are, they may now be regarded as having been satisfactorily explained. Long ago Buffon sought to account for the hexagonal form of the cells by an hypothesis of mutual pressure. Supposing the bees to have a tendency to build tubular cells, if a greater number of bees were to build in a given space than could admit of all the parallel tubes being completed, tubes with flat sides and sharp angles might result, and if the mutual pressure were exactly equal in all directions, these sides and angles would assume the form of hexagons. This hypothesis of Buffon was sustained by such physical analogies as the blowing of a crowd of soap-bubbles in a cup, the swelling of moistened peas in a confined space, &c. The hypothesis, however, as thus presented was clearly inadequate; for no reason is assigned why the mutual pressure, even if conceded to exist, should always be so exactly equal in all directions as to convert all the cylinders into perfect hexagons--even the analogy of the soap-bubbles and the moistened peas failing, as pointed out by Brougham and others, to sustain it, seeing that as a matter of fact bubbles and peas under circumstances of mutual pressure do not assume the form of hexagons, but, on the contrary, forms which are conspicuously irregular. Moreover, the hypothesis fails to account for the particular prismatic shape presented by the cell base. Therefore it is not surprising that this hypothesis should have gained but small acceptance. Kirby and Spence dispose of it thus:--'He (Buffon) gravely tells us that the boasted hexagonal cells of the bee are produced by the reciprocal pressure of the cylindrical bodies of these insects against each other!!'[59] The double note of admiration here may be taken to express the feelings with which this hypothesis of Buffon was regarded by all the more sober-minded naturalists. Yet it turns out to have been not very wide of the mark. As is often the case with the gropings of a great mind, the idea contains the true principle of the explanation, although it fails as an explanation from not being in a position to take sufficient cognizance of all the facts. Safer it is for lesser minds to restrain their notes of exclamation while considering the theories of a greater; however crude or absurd the latter may appear, the place of their birth renders it not impossible that some day they may prove to have been prophetic of truth revealed by fuller knowledge. Usually in such cases the final explanation is eventually reached by the working of a yet greater mind, and in this case the undivided credit of solving the problem is to be assigned to the genius of Darwin.

Mr. Waterhouse pointed out 'that the form of the cell stands in close relation to the presence of adjoining cells.' Starting from this fact, Mr. Darwin says,--

Let us look to the great principle of gradation, and
see whether Nature does not reveal to us her method of
work. At one end of a short series we have
humble-bees, which use their old cocoons to hold
honey, sometimes adding to them short tubes of wax,
and likewise making separate and very irregular
rounded cells of wax. At the other end of the series
we have the cells of the hive-bee, placed in a double
layer. . . . In the series between the extreme perfection
of the cells of the hive-bee and the simplicity of
those of the humble-bee we have the cells of the
Mexican _Melipona domestica_, carefully described and
figured by Pierre Huber. . . . It forms a nearly regular
waxen comb of cylindrical cells, in which the young
are hatched, and, in addition, some large cells of wax
for holding honey. These latter cells are nearly
spherical and of nearly equal sizes, and are
aggregated into an irregular mass. But the important
thing to notice is, that these cells are always made
at that degree of nearness to each other that they
would have intersected or broken into each other if
the spheres had been completed; but this is never
permitted, the bees building perfectly flat cells of
wax between the spheres which thus tend to intersect.
Hence each cell consists of an outer spherical
portion; and of two, three, or more flat surfaces,
according as the cell adjoins two, three, or more
other cells. When one cell rests on three other cells,
which, from the spheres being nearly of the same size,
is very frequently and necessarily the case, the three
flat surfaces are united into a pyramid; and this
pyramid, as Huber has remarked, is manifestly a gross
imitation of the three-sided pyramidal base of the
cell of the hive-bee. . . .

Reflecting on this case, it occurred to me that if the
Melipona had made its spheres at some given distance
from each other, and had made them of equal sizes, and
had arranged them symmetrically in a double layer, the
resulting structure would have been as perfect as the
comb of the hive-bee. Accordingly I wrote to Prof.
Miller of Cambridge, and this geometer has kindly read
over the following statement, drawn up from his
information, and tells me that it is strictly correct.

This statement having fully borne out his theory, Mr. Darwin continues:--

Hence we may safely conclude that, if we could
slightly modify the instincts already possessed by the
Melipona, and in themselves not very wonderful, this
bee would make a structure as wonderfully perfect as
that of the hive-bee. We must suppose the Melipona to
have the power of forming her cells truly spherical,
and of equal sizes; and this would not be very
surprising, seeing that she already does so to a
certain extent, and seeing what perfectly cylindrical
burrows many insects make in wood, apparently by
turning round on a fixed point. We must suppose the
Melipona to arrange her cells in level layers, as she
already does her cylindrical cells; and we must
further suppose--and this is the greatest
difficulty--that she can somehow judge accurately at
what distance to stand from her fellow-labourers when
several are making their spheres; but she is already
so far able to judge of distance that she always
describes her spheres so as to intersect to a certain
extent; and then she unites the points of intersection
by perfectly flat surfaces. By such modifications of
instinct, which in themselves are not very
wonderful--hardly more wonderful than those which
guide a bird to make its nest,--I believe that the
hive-bee has acquired through natural selection her
inimitable architectural powers.[60]

Mr. Darwin next tested this theory by the experiment of introducing into beehives plates of wax, and observing that the bees worked upon these plates just as the theory required. That is to say, they made their cells by excavating a number of little circular pits at equal distances from one another, so that by the time the pits had acquired the width of an ordinary cell, the sides of the pits intersected. As soon as this occurred the bees ceased to excavate, and instead began to build up flat walls of wax on the lines of intersection. Other experiments with very thin plates of vermilion-coloured wax showed that the bees all worked at about the same rate, and on opposite sides of the plates, so that the common bottoms of any two opposite pits were flat. These flat bottoms 'were situated, as far as the eye could judge, exactly along the planes of imaginary intersection between the basins on the opposite sides of the ridge of wax;' so that if the plate of wax had been thick enough to admit of the opposite basins being deepened (and widened) into cells, the mutual intersection of _adjacent_ as well as _opposite_ bottoms would have given rise, as in the first experiment with the thick plate of wax, to the pyramidal bottoms. Experiments with the vermilion wax also showed, as Huber had previously stated, that a number of individual bees work by turns at the same cell; for by covering parts of growing cells with vermilion wax, Mr. Darwin--

Invariably found that the colour was most delicately
diffused by the bees--as delicately as a painter could
have done it with his brush--by atoms of the coloured
wax having been taken from the spot on which it had
been placed, and worked into the growing edges of the
cells all round.

Such, omitting details, is the substance of Mr. Darwin's theory. In summary he concludes,--

The work of construction seems to be a sort of balance
struck between many bees, all instinctively standing
at the same relative distance from each other, all
trying to sweep equal spheres, and then building up,
or leaving ungnawed, the planes of intersection
between these spheres.

This theory, while serving as a full and simple explanation of all the facts, has, as we have seen, been so fully substantiated by observation and experiment, that it deserves to be regarded as raised to the rank of a completed demonstration. It differs from the theory of Buffon in two important particulars: it embraces all the facts, and supplies a cause adequate to explain them. This cause is natural selection, which converts the random 'pressure' in Buffon's theory into a precisely regulated principle. Random pressure alone could never produce the beautifully symmetrical form of the hexagonal cell with the pyramidal bottom; but it could and must have produced the intersection of cylindrical cells among possibly many extinct species of bees, such as the Melipona. Whenever this intersection occurred in crowded nests, it must clearly have been of great benefit in securing economy of precious wax; for in every case where a flat wall of partition between two adjacent cells did duty instead of a double cylindrical wall of separate cells, there wax should have been saved. Thus we can see how natural selection would have worked towards the developing of an instinct to excavate cells near enough together to produce intersection; and once begun, there is no reason why this instinct should not have been perfected by the same agency, till we meet with its ideal perfection in the hive-bee. For as Mr. Darwin observes,--

With respect to the formation of wax, it is known that
bees are often hard pressed to get sufficient nectar;
and I am informed by Mr. Tegetmeier that it has been
experimentally proved that from twelve to fifteen
pounds of dry sugar are consumed by a hive of bees for
the secretion of a pound of wax; so that a prodigious
quantity of fluid nectar must be collected and
consumed by the bees in a hive for the secretion of
the wax necessary for the construction of their combs.
Moreover, many bees have to remain idle for many days
during the process of secretion. . . . Hence it would
continually be more and more advantageous to our
humble-bees if they were to make their cells more and
more regular, nearer together, and aggregated into a
mass, like the cells of Melipona; for in this case a
large part of the bounding surface of each cell would
serve to bound the adjoining cell, and much labour and
wax would be saved. Again, from the same cause, it
would be advantageous to the Melipona if she were to
make her cells closer together, and more regular in
every way than at present; for then, as we have seen,
the spherical surfaces would wholly disappear and be
replaced by plane surfaces; and the Melipona would
make a comb as perfect as that of the hive-bee. Beyond
this stage of perfection in architecture, natural
selection could not lead; for the comb of the
hive-bee, as far as we can see, is absolutely perfect
in economising labour and wax.

The problem, then, as to the origin and perfection of the cell-making instinct appears thus to have been fully and finally solved. I shall now adduce a few facts to show that while the general instinct of building hexagonal cells has doubtless been acquired by natural selection in the way just explained, it is nevertheless an instinct not wholly of a blind or mechanical kind, but is constantly under the control of intelligent purpose. Thus Mr. Darwin observes,--

It was really curious to note in cases of difficulty,
as when two pieces of comb met at an angle, how often
the bees would pull down and rebuild in different ways
the same cell, sometimes recurring to a shape which
they had at first rejected.[61]

Again, Huber saw a bee building upon the wax which had already been put together by her comrades. But she did not arrange it properly, or in a way to continue the design of her predecessors, so that her building made an undesirable corner with theirs. 'Another bee perceived it, pulled down the bad work before our eyes, and gave it to the first in the requisite order, so that it might exactly follow the original direction.' Similarly, to quote Büchner,--

All the cells have not the same shape, as would be the
case if the bees in building worked according to a
perfectly instinctive and unchangeable plan. There are
very manifold changes and irregularities. Almost in
every comb irregular and unfinished cells are to be
found, especially where the several divisions of a
comb come together. The small architects do not begin
their comb from a single centre, but begin building
from many different points, so as to progress as
rapidly as possible, and so that the greatest number
may work simultaneously; they therefore build from
above downwards, in the shape of flat truncated cones
or hanging pyramids, and these several portions are
afterwards united together during the winter budding.
At these lines of junction it is impossible to avoid
irregular cells between the pressed together or
unnaturally lengthened ones. The same is true more or
less of the passage cells, which are made to unite the
large cells of the so-called drone wax with the
smaller ones of the working bees, and which are
generally placed in two or three rows. The cells also
which they usually build from the combs to the glass
walls of their hives, in order to hold them up, show
somewhat irregular forms. Finally, in places where
special conditions of the situation do not otherwise
permit, it may be observed that the bees, far from
clinging obstinately to their plan, very well
understand how to accommodate themselves to
circumstances not only in cell-building, but also in
making their combs. F. Huber tried to mislead their
instinct, or rather to put to the proof their reason
and cleverness in every possible way, but they always
emerged triumphant from the ordeal. For instance, he
put bees in a hive the floor and roof of which were
made of glass, that is of a body which the bees use
very unwillingly for the attachment of their combs, on
account of its smoothness. Thus the possibility of
building as usual from above downwards, and also from
below upwards, was taken away from them; they had no
point of support save the perpendicular walls of their
dwelling. They thereupon built on one of these walls a
regular stratum of cells, from which, building
sideways, they tried to carry the comb to the opposite
side of the hive. To prevent this Huber covered that
side also with glass. But what way out of the
difficulty was found by the clever insects? Instead of
building further in the projected direction, they bent
the comb round at the extreme point, and carried it at
a right angle towards one of the inner sides of the
hive which was not covered with glass, and there
fastened it. The form and dimensions of the cells must
necessarily have been altered thereby, and the
arrangement of their work at the angle must have been
quite different from the usual. They made the cells of
the convex side so much broader than those of the
concave that they had a diameter two or three times as
great, and yet they managed to join them properly with
the others. They also did not wait to bend the comb
until they came to the glass itself, but recognised
the difficulty beforehand,[62] which had been
interposed by Huber while they were building with a
view to overcome the first difficulty.

_Special Habits._

_The Mason-Bee._--This insect closes the roof of its larval cell with a kind of mortar, which sets as hard as stone. A little hole, closed only with soft mud, is, however, left in one part of the roof as a door of exit for the matured insect. It is said that when a mason-bee finds an old and deserted nest, it saves itself the trouble of making a new one--utilising the ready-made nest after having well cleaned it. In Algiers the mason-bees have been observed in this way to utilise empty snail-shells. According to Blanchard, some individuals avoid the labour of making their own nests or houses for their young, by possessing themselves of their neighbours' houses either by craft or by force. 'Does the mason-bee act like a machine,' says E. Menault, 'when it directs its work according to circumstances, possesses itself of old nests, cleanses and improves them, and thereby shows that it can fully appreciate the immediate position? Can one believe that no kind of reflection is here necessary?'

_The Tapestry-Bee._--The so-called tapestry-bee digs holes for her larvæ three or four inches deep in the earth, and lines the walls and floor of the chamber with petals of the poppy laid perfectly smooth. Several layers of petals are used, and when the eggs are introduced the chamber is closed by drawing all the leaves together at the top. Loose earth is then piled over the whole structure in order to conceal it. The so-called rose-bee (_Megachile centuncularis_) displays very similar habits.[63]

_The Carpenter-Bee._--This was first observed and described by Réaumur.[64] It makes a long cylindrical tube in the wood of beams, palings, &c. This it divides into a number of successive chambers by partitions made of agglutinated saw-dust built across the tube at right angles to its axis. In each chamber there is deposited a single egg, together with a store of pollen for the nourishment of the future larva. The larvæ hatch out in succession and in the order of their age--_i.e._ the dates at which they were deposited. To provide for this, the bee bores a hole from the lower cell to the exterior, so that each larva, when ready to escape from its chamber, finds an open way from the tube. The larvæ have to cut their own way out through the walls of their respective chambers, and it is remarkable that they always cut through the wall that faces the tubular passage left by the parent; they never bore their way out in the opposite direction, which, were they to do so, would entail the destruction of all the other and immature larvæ.

_The Carding-Bee._--This insect surrounds its nest with a layer of wax, and then with a thick covering of moss. For this purpose a number of bees co-operate, and in order to save time each bee does not find and carry its own moss, but, with a division of labour similar to that which we have already noticed in the case of certain ants, a row of bees is formed, and the bits of moss passed from one to another along the line. There is a long passage to the nest, through which the moss has to be passed, and it is said that at the mouth of the tunnel a guard is stationed to drive away ants or other intruders.

_Wasps._--These usually construct their nests of wood-dust, which they scrape off the weather-worn surfaces of boards, palings, &c., and work into a kind of paper with their saliva. If they happen to find any real paper, they perceive that it so much resembles the product of their own manufacture that they utilise it forthwith. The wasps do not require any special cells or chambers for the storage of honey, as they do not lay up any supply for the winter. The cells which they construct are therefore used exclusively for the rearing of larvæ. In form these cells are sometimes cylindrical or globular, but more usually hexagonal, like those of the hive-bee. Although the mode of building is different from that employed by the bees, there can be little doubt that if it were as carefully investigated Mr. Darwin's theory of transition from the cylindrical to the hexagonal form would be found to apply here also, seeing that both forms so frequently occur in the same nest.

_The Mason-Wasp._--The habits of this insect are described by Mr. Bates. It constructs its nest of clay. Each pellet that the insect brings it lays on the top of its nest-wall, and then spreads it out with its jaws, and treads it smooth with its feet. The nest, which is suspended on the branch of a tree, is then stocked with spiders and insects paralysed by stinging. The victims, not being wholly deprived of life, keep fresh until required as food of the developing larvæ.

_The Butcher-Wasps._--These also paralyse their prey in a similar manner, and for a similar purpose. Fabre removed from a so-called sphex-wasp a killed grasshopper, which it was conveying to its nest and had momentarily laid down at the mouth of the burrow--as these insects always do on returning with prey, in order to see that nothing has intruded into the burrow during their absence. Fabre carried the dead or paralysed grasshopper to a considerable distance from the hole. On coming out the insect searched about until it found its prey. It then again carried it to the mouth of its burrow, and again laid it down while it once more went in to see that all was right at home. Again Fabre removed the grasshopper, and so on for forty times in succession--the sphex never omitting to go through its fixed routine of examining the interior of its burrow every time that it brought the prey to its mouth.

Mr. Mivart, in his 'Lessons from Nature,' points to the instinct of this animal in the stinging of the ganglion of its prey as one that cannot be explained on Mr. Darwin's theory concerning the origin of instincts. In my next work, which will have to deal with this theory, I shall consider Mr. Mivart's difficulty, and also the difficulty first pointed out by Mr. Darwin himself as to why neuter insects, separated as they appear to be from the possibility of communicating by heredity any instinctive acquirements of the individual to the species, should present any instincts at all.

_General Intelligence._

Beginning with Sir John Lubbock's observations on this head, I shall first quote his statements with regard to way-finding:--

I have found, he says, that some bees are much more
intelligent in this respect than others. A bee which I
had fed several times, and which had flown about in
the room, found its way out of the glass in a quarter
of an hour, and when put in a second time came out at
once. Another bee, when I closed the postern door,
used to come round to the honey through an open
window.

Bees seem to me much less clever in finding things
than I had expected. One day (April 14, 1872), when a
number of them were very busy on some barberries, I
put a saucer with some honey between two bunches of
flowers; these were repeatedly visited, and were so
close that there was hardly room for the saucer
between them, yet from 9.30 to 3.30 not a single bee
took any notice of the honey. At 3.30 I put some
honey on one of the bunches of flowers, and it was
eagerly sucked by the bees; two kept continually
returning till past five in the evening.

One day when I came home in the afternoon I found that
at least a hundred bees had got into my room through
the postern and were on the window, yet not one was
attracted by an open jar of honey which stood in a
shady corner about 3 feet 6 inches from the window.

One day (29th April, 1872) I placed a saucer of honey
close to some forget-me-nots, on which bees were
numerous and busy; yet from 10 A.M. till 6 only one
bee went to the honey.

I put some honey in a hollow in the garden wall
opposite the hives at 10.30 (this wall is about five
feet high and four feet from the hives); yet the bees
did not find it during the whole day.

On the 30th March, 1873, a fine sunshiny day, when the
bees were very active, I placed a glass containing
honey at 9 in the morning on the wall in front of the
hives; but not a single bee went to the honey the
whole day. On April 20 I tried the same experiment,
with the same result.

September 19.--At 9.30 I placed some honey in a glass
about four feet from and just in front of the hive;
but during the whole day not a bee observed it.

As it then occurred to me that it might be suggested
that there was something about this honey which
rendered it unattractive to the bees, on a following
day I placed it again on the top of the wall for three
hours, during which not a single bee came, and then
moved it close to the alighting-board of the hive. It
remained unnoticed for a quarter of an hour, when two
bees observed it; and others soon followed in
considerable numbers. . . . On the whole, wasps seem to
me more clever in finding their way than bees. I tried
wasps with the glass mentioned on p. 124 [_i.e._ the
bell-jar], but they had no difficulty in finding their
way out.

We shall now conclude this _résumé_ of Sir John Lubbock's observations by quoting two other passages bearing on the general intelligence of bees and wasps:--

The following fact struck me as rather remarkable. The
wasp already mentioned at the foot of p. 135 one day
smeared her wings with syrup, so that she could not
fly. When this happened to a bee, it was only
necessary to carry her to the alighting-board, when
she was soon cleaned by her comrades. But I did not
know where this wasp's nest was, and therefore could
not pursue a similar course with her. At first, then,
I was afraid that she was doomed. I thought, however,
that I would wash her, fully expecting, indeed, to
terrify her so much that she would not return again. I
therefore caught her, put her in a bottle half full of
water, and shook her up well till the honey was washed
off. I then transferred her to a dry bottle and put
her in the sun. When she was dry I let her out, and
she at once flew to her nest. To my surprise, in
thirteen minutes she returned, as if nothing had
happened, and continued her visits to the honey all
the afternoon.

This experiment interested me so much that I repeated
it with another marked wasp, this time, however,
keeping the wasp in the water till she was quite
motionless and insensible. When taken out of the water
she soon recovered; I fed her; she went quietly away
to her nest as usual, and returned after the usual
absence. The next morning this wasp was the first to
visit the honey.

I was not able to watch any of the above-mentioned
wasps for more than a few days; but I kept a specimen
of _Polistes Gallica_ for no less than nine months.

This is the wasp which has already been alluded to under the heading 'Memory;' but it is evident that the capacity which the insect displayed of becoming tamed implies no small degree of general intelligence; its hereditary instincts were conspicuously modified by the individual experiences incidental to its domestication.

The remaining passages that deserve quotation are the following:--

It is sometimes said of bees that those of one hive
all know one another, and immediately recognise and
attack any intruder from another hive. At first sight
this certainly implies a great deal of intelligence.
It is, however, possible that the bees of particular
hives have a particular smell. Thus Langshaft, in his
interesting 'Treatise on the Honey-Bee,' says:
'Members of different colonies appear to recognise
their hive companions by the sense of smell; and I
believe that if colonies are sprinkled with scented
syrup, they may generally be safely mixed. Moreover, a
bee returning to its own hive with a load of treasure
is a very different creature from a hungry marauder;
and it is said that a bee, if laden with honey, is
allowed to enter any hive with impunity.' Mr.
Langshaft continues, 'There is an air of roguery about
a thieving bee which, to the expert, is as
characteristic as are the motions of a pickpocket to a
skilful policeman. Its sneaking look, and nervous,
guilty agitation, once seen, can never be mistaken.'
It is, at any rate, natural that a bee which enters a
wrong hive by accident should be much surprised and
alarmed, and would thus probably betray herself.

On the whole, then, I do not attach much importance to
their recognition of one another as an indication of
intelligence.

Since their extreme eagerness for honey may be
attributed rather to their anxiety for the common weal
than to their desire for personal gratification, it
cannot fairly be imputed as greediness; still the
following scene, one which most of us have witnessed,
is incompatible surely with much intelligence. The sad
fate of their unfortunate companions does not in the
least deter others who approach the tempting lure from
madly alighting on the bodies of the dying and dead,
to share the same miserable end. No one can understand
the extent of their infatuation until he has seen a
confectioner's shop assailed by myriads of hungry
bees. I have seen thousands strained out from the
syrup in which they had perished; thousands more
alighting even upon the boiling sweets, the floor
covered and windows darkened with bees, some crawling,
others flying, and others still, so completely
besmeared as to be able neither to crawl nor fly, not
one in ten able to carry home its ill-gotten spoils,
and yet the air filled with new hosts of thoughtless
comers.

Passing on now to the statements of other observers, Huber first noticed the remarkable fact that when beehives are attacked by the death's-head moth the bees close the entrance of their hive with wax and propolis to keep out the marauder. The barricade, which is built immediately behind the gateway, completely stops it up--only a small hole being left large enough to admit a bee, and therefore of course too small to admit the moth. Huber specially states that it was not until the beehives had been _repeatedly_ attacked and robbed by the death's-head moth, that the bees closed the entrance of their hive with wax and propolis. _Pure_ instinct would have induced the bees to provide against the first attack. Huber also observed that a wall built in 1804 against the death's-head hawk-moth was destroyed in 1805. In the latter year there were no death's-head moths, nor were any seen during the following. But in the autumn of 1807 a large number again appeared, and the bees at once protected themselves against their enemies. The bulwark was destroyed again in 1808.

Again, Huber (_loc. cit._, tom. ii., p. 280) gives a case of apparent exercise of reason, or power of inference from a particular case to other and general cases. A piece of comb fell down and was fixed in its new position by wax. The bees then strengthened the attachments of all the other combs, clearly because they inferred that they too might be in danger of falling. This is a very remarkable case, and leads Huber to exclaim, 'I admit that I was unable to avoid a feeling of astonishment in the presence of a fact from which the purest reason seemed to shine out.'

A closely similar, and therefore corroborative case of an even more remarkable kind is thus narrated in Watson's 'Reasoning Power of Animals' (p. 448):--

Dr. Brown, in his book on the bee, gives another
illustration of the reasoning power of bees, observed
by a friend of his. A centre comb in a hive, being
overburdened with honey, had parted from its
fastenings, and was pressing against another comb, so
as to prevent the passage of the bees between them.
This accident excited great bustle in the colony, and
as soon as their proceedings could be observed, it was
found that they had constructed two horizontal beams
between the two combs, and had removed enough of the
honey and wax above them to admit the passage of a
bee, while the detached comb had been secured by
another beam, and fastened to the window with spare
wax. But what was most remarkable was, that, when the
comb was thus fixed, they removed the horizontal beams
first constructed, as being of no further use. The
whole occupation took about ten days.

Again, Mr. Darwin's MS. quotes from Sir B. Brodie's 'Psychological Inquiries' (1854, p. 88) the following case, which is analogous to the above, except that the supports required had to be made in a vertical instead of in a horizontal direction:--

On one occasion, when a large portion of the honeycomb
had been broken off, they pursued another course. The
fragment had somehow become fixed in the middle of the
hive, and the bees immediately began to erect a new
structure of comb on the floor, so placed as to form a
pillar supporting the fragment, and preventing its
further descent. They then filled up the space above,
joining the comb which had become detached to that
from which it had been separated, and they concluded
their labours by removing the newly constructed comb
below, thus proving that they had intended it to
answer a merely temporary purpose.

Similarly, Dr. Dzierzon, an experienced keeper of bees, and the observer who first discovered the fact of their parthenogenesis, makes the general remark,--

The cleverness of the bees in repairing perfectly
injuries to their cells and combs, in supporting on
pillars pieces of their building accidentally knocked
down by a hasty push, in fastening them with rivets,
and bringing everything again into proper unity,
making hanging bridges, chains, and ladders, compels
our astonishment.

Lastly, as still further corroboration of such facts, I shall quote the following from Jesse's 'Gleanings:'[65]--

Bees show great ingenuity in obviating the
inconvenience they experience from the slipperiness of
glass, and certainly beyond what we can conceive that
mere instinct would enable them to do. I am in the
habit of putting small glass globes on the top of my
straw hives, for the purpose of having them filled
with honey; and I have invariably found that before
the bees commence the construction of combs, they
place a great number of spots of wax at regular
distances from each other, which serve as so many
footstools on the slippery glass, each bee resting on
one of these with its middle pair of legs, while the
fore claws were hooked with the hind ones of the bee
next above him; thus forming a ladder, by means of
which the workers were enabled to reach the top, and
begin to make their combs there.

Herr Kleine, in his pamphlet on Italian Bees and Bee-keeping (Berlin, 1855), says that on substituting during the absence of the bees a hive filled with empty comb for their own hive, the returning bees exhibit the utmost perplexity. As the substituted hive stands in the exact spot previously occupied by their own hive, the returning bees fly into it without observing the change. But finding only empty combs inside, 'they stop, do not know where they are, come out of the hole again without depositing their loads, fly off, look most carefully round the stand to assure themselves that they have made no mistake, and go in once more when convinced that they are at the right place. The same thing is repeated over and over again, until the bees at last bow to the incomprehensible and unavoidable, lay down their loads, and set to work at those tasks made necessary by the new circumstances of the hive. But as all the newly arriving bees behave in similar fashion, the disturbance lasts till late in the evening, and the uncertainty and anxiety of the bees is so great that the bee-master cannot contemplate it without deep sympathy.' Under such circumstances the bees take quickly to a substituted queen; 'for the feeling of the first comers that they have no right to the new dwelling, having, as they suppose, made some inexplicable mistake which they cannot remedy, prevents them from feeling any hostility to the new queen which they find; they probably consider themselves as merely on sufferance, and feel that they should be grateful that no action is taken against them for their illegal entry, as generally happens in bee-experience.' Hence the writer adopts this device when he desires to exchange or substitute queens.

Büchner, after alluding to this case, supplements it with the following:--

The wind threw down from the stand of a bee-master--a
friend of the author's, whose name will soon become
known--a straw beehive, the inmates of which were
surprised in full work, and no small disorder in the
interior was the result. The owner repaired the hive,
put the loose comb back in its place, and replaced it
in such a manner that the wind could not again catch
it, hoping that the accident would have no further
results. But when he examined the hive a few days
later, he found that the bees had left their old home
in the lurch, and had tried to enter other hives,
clearly because they could no longer trust the
weather, and feared that the terrible accident might
again befall them.

Dr. Erasmus Darwin, in his 'Zoonomia,' asserts that bees, when transported to Barbadoes, where there is no winter, cease to lay up honey. In contradiction to this statement, however, Kirby and Spence say, 'It is known to every naturalist acquainted with the fact, that many different species of bees store up honey in the hottest climates, and that there is no authentic instance on record of the hive-bees altering in any age or climate their peculiar operations.'

On the other hand, more recent observation has shown that Dr. Darwin's statement is probably correct. For, according to a note in _Nature_,[66] European bees, when transported to Australia, retain their industrious habits only for the first two or three years. After that time they gradually cease to collect honey till they become wholly idle. In a subsequent number of the same periodical (p. 411) a correspondent writes that the same fact is observable with bees transported to California, but is obviated by abstracting honey as the bees collect it.