THE MODERN THEORY OF INSTINCT
The larvæ of the various Hunting Wasps require their prey to be
incapable of movement, so that there may be no resistance on the
victim’s part, which would be a source of danger to the fragile egg
and, later, to the grub. Moreover, for all its lethargy, it must still
be alive; for the grub would refuse to feed on a corpse. The fare
provided must be fresh meat and not preserved stuff. I have already
laid stress on these two antagonistic conditions, immobility and life,
and enlarged on them so fully that I need hardly dwell upon them for a
second time. I have shown how the Wasp realizes them by the medium of a
paralysis which destroys movement and leaves the organic principle of
life intact. With a skill which our most famous vivisectors would envy,
the insect drives its poisoned sting into the nerve-centres, the seat
of muscular incitation. The operator confines herself to one stroke of
the lancet, or else gives two, three or more, according to the
structure of the particular nervous system and to the number and
grouping of the ganglia. The course of the sting is determined by the
exact anatomy of the victim.
The particular prey of the Hairy Ammophila is a caterpillar, each of
whose nerve-centres, which are distant one from the other and to a
certain extent independent in their action, occupies a different
segment of the insect. This caterpillar, who is a very lively customer,
cannot be stored in the cell, with the Wasp’s egg upon his flank, until
he has lost all his power of motion. One movement of his body would
crush that egg against the wall of the cell.
Now the paralysis of one segment would not mean that the next was also
rendered incapable of movement, because of the comparative independence
of the seats of innervation. It is necessary, therefore, that all the
segments, or at least the most important, be operated on, one after the
other, from the first to the last. The course which the Ammophila
adopts is that which the most experienced of physiologists would
recommend: her sting is transferred from one segment to the next, nine
separate times over.
She does better than that. The victim’s head is still unscathed, the
mandibles are at work: they might easily, as the insect is borne along,
grip some bit of straw in the ground and successfully resist this
forcible removal; the brain, the primary nervous centre, might provoke
a stubborn contest, which would be very awkward with so heavy a burden.
It is well that these hitches should be avoided. The caterpillar,
therefore, must be reduced to a state of torpor which will deprive him
of the least inclination for self-defence. The Ammophila succeeds in
effecting this by munching his head. She takes good care not to use her
needle: she is no clumsy bungler and knows quite well that to inflict a
mortal wound on the cervical ganglia would mean killing the caterpillar
then and there, the very thing to be avoided. She merely squeezes the
brain between her mandibles, calculating every pinch; and, each time,
she stops to ascertain the effect produced, for there is a nice point
to be achieved, a certain degree of torpor that must not be exceeded,
lest death should supervene. In this way the requisite lethargy is
obtained, a somnolence in which all volition is lost. And now the
caterpillar, incapable of resistance, incapable of wishing to resist,
is seized by the nape of the neck and dragged to the nest. Comment
would mar the eloquence of such facts as these.
The Hairy Ammophila has twice allowed me to attend her surgical
operations. I have described in an earlier chapter of this volume my
first observation, which dates many years back. On that occasion I
witnessed the performance quite unexpectedly; to-day, I have made all
my preparations and have plenty of time at my disposal, so that I am
able to make a much more thorough observation. In each case there was a
multiplicity of needle-pricks, which were distributed methodically,
from front to back, along the ventral surface. Is the number of stings
indeed identical in both cases? This time, it is exactly nine. In the
case of the victim which I saw paralysed on the Plateau des Angles, it
seemed to me that the weapon inflicted more wounds, though I am not
able to state the precise number. It is quite possible that this number
varies slightly and that the last segments of the caterpillar, being
much less important than the others, are attacked or left alone
according to the size and strength of the quarry to be incapacitated.
On the second occasion, moreover, I had my first view of the squeezing
process to which the caterpillar’s brain is subjected, a process that
produces the torpor which makes the transport and storage of the victim
possible. So remarkable a fact would not have escaped me in the first
instance; it did not, therefore, take place. It follows that this
cerebral compression is a resource which the Wasp has at her disposal,
for use when circumstances demand it, as for instance when the victim
seems likely to offer resistance on the road.
The malaxation of the cervical ganglia is optional: it has no bearing
on the future of the larva; the Wasp practises it, when needful, to
facilitate transport. I have seen the Languedocian Sphex, who gave me
so much trouble in the old days, at work fairly often, but only once
has she performed this operation on the neck of her Ephippiger in my
presence. The invariable and absolutely necessary part of the Hairy
Ammophila’s procedure seems therefore to be the multiplicity of stings
and their distribution one by one over all or nearly all the
nerve-centres along the median line of the lower surface.
Let us place side by side with the murderous art of the Wasp the
murderous art of man, practical man, whose business it is to slay
rapidly. I will here recall one of my childhood’s memories. We were
schoolboys of twelve years old, or thereabouts. We were being
instructed in the woes of Melibœus, pouring out his sorrows on the
bosom of Tityrus, who offers him his chestnuts, his sour milk and his
bed of fresh bracken; [52] we were made to recite a poem by Racine the
Younger, [53] La Religion. A curious poem, forsooth, for children who
cared more for marbles than theology! I remember just two lines and a
half:
... et, jusque dans la fange,
L’insecte nous appelle et, certain de son prix,
Ose nous demander raison de nos mépris. [54]
Why do these two lines and a half linger in my memory and none of all
the rest? Because already Scarabæus and I were friends. Those two lines
and a half bothered me: I thought it a very absurd idea to relegate you
to the mire, ye insects so seemly clad, so elegantly groomed. I knew
the bronze harness of the Carabus, the Russia-leather jerkin of the
Stag-beetle; I knew that the least of you possesses an ebon sheen and
gleams of precious metals; and therefore the mire wherein the poet
flung you shocked me somewhat. If M. Racine Junior had nothing better
to say about you, he might as well have held his tongue; but he did not
know you, and in his day there were only just a few who were beginning
to have a dim conception of your nature.
While going over some passage of the tiresome poem for the next day’s
lesson, I would indulge my fancy for another kind of education. I
visited the Linnet in her nest, on a juniper-bush standing as high as
myself; I watched the Jay picking an acorn on the ground; I came upon
the Crayfish, still quite soft after shedding his shell; I made
inquiries as to the exact date when the Cockchafers were due; I went in
quest of the first full-blown Cuckoo-flower. Plants and animals, that
wondrous poem of which a faint echo was beginning to wake in my young
brain, made a very pleasant change from the uninspiring alexandrine.
The problem of life and that other one, with its dark terrors, the
problem of death, at times passed through my mind. It was a fleeting
obsession, soon forgotten by the mercurial spirits of youth.
Nevertheless, the tremendous question would recur, brought to mind by
this incident or that.
Passing one day by a slaughter-house, I saw an Ox driven in by the
butcher. I have always had an insurmountable horror of blood; when I
was a boy, the sight of an open wound affected me so much that I would
fall into a swoon, which on more than one occasion nearly cost me my
life. How did I screw up courage to set foot in those shambles? No
doubt, the dread problem of death urged me on. At any rate, I entered,
close on the heels of the Ox.
With a stout rope round its horns, wet-muzzled, meek-eyed, the animal
moves along as though making for the crib in its stable. The man walks
ahead, holding the rope. We enter the hall of death, amid the sickening
stench thrown up by the entrails scattered over the ground and the
pools of blood. The Ox becomes aware that this is not his stable; his
eyes turn red with terror; he struggles; he tries to escape. But an
iron ring is there, in the floor, firmly fixed to a stone flag. The man
passes the rope through it and hauls. The Ox lowers his head; his
muzzle touches the ground. While an assistant keeps him in this
position with the rope, the butcher takes a knife with a pointed blade,
not at all a formidable knife, hardly larger than the one which I
myself carry in my breeches-pocket. For a moment he feels with his
fingers at the back of the animal’s neck and then drives in the blade
at the chosen spot. The great beast gives a shiver and drops, as though
struck by lightning: procumbit humi bos, as we used to say in those
days.
I fled from the place like one possessed. Afterwards I wondered how it
was possible, with a knife almost identical with that which I used for
prizing open my walnuts and taking the skin off my chestnuts, with that
insignificant blade, to kill an Ox and kill him so suddenly. No gaping
wound, no blood spilt, not a bellow from the animal. The man feels with
his finger, gives a jab and the thing is done: the Bullock’s legs
double up under him.
This instantaneous death, this lightning-stroke, remained an awesome
mystery to me. It was only later, very much later, that I learnt the
secret of the slaughter-house, at a time when, in the course of my
promiscuous reading, I was picking up a smattering of anatomy. The man
had cut through the spinal marrow where it leaves the skull; he had
severed what our physiologists have called the vital cord. To-day I
might say that he had operated in the manner of the Wasps, whose lancet
plunges into the nerve-centres.
Let us watch this spectacle a second time, under more exciting
conditions: I mean, in the saladeiros of South America, those immense
establishments for killing and treating meat, where they slaughter as
many as twelve hundred Oxen a day. I will quote the account of an
eye-witness: [55]
‘The cattle arrive in large herds and the matance begins on the day
after the arrival. A whole herd is confined in an enclosed space,
or margueira. From time to time men on horseback drive fifty or
sixty beasts into a narrower and stronger enclosure, with a sloping
floor of brick, boards or concrete, which is always very slippery.
A special operator, standing on an outer platform which runs along
the wall of the smaller margueira, lassoes one of the crowd of
animals by the head or, more often, by the horns. The middle
portion of the long, stout lasso is coiled round a windlass; and a
draught-horse, or sometimes a pair of oxen, drags the lassoed beast
along and makes it slide, in spite of its struggles, right against
the windlass, where it is brought up with a thud and remains
without power of movement.
‘Another assistant, the desnucador, also standing on the platform,
has then but to stick a knife, at the back of the head, between the
occipital bone and the axis; and the paralysed animal topples on to
a trolley in which it is carted off. It is at once thrown on an
inclined plane where other special labourers bleed it and skin it.
But, as the injury to the cervical marrow varies a good deal in
position and extent, it often happens that the unfortunate beasts
still retain the motions of the heart and of the respiratory
organs; and, in such cases, they suffer a reaction under the knife;
they utter faint sounds of pain and move their limbs, while already
half-flayed and disembowelled. Nothing could be more painful than
the sight of all those animals skinned alive, cut up and
transformed by those men, covered with blood, who run about in all
directions.’
The murderous methods of the saladeiro are an exact repetition of what
I had seen in the slaughter-house. In both these lethal work-shops they
pierce the vertebral marrow at the base of the skull. The Ammophila
operates in a similar fashion, with this difference, that her surgery
is much more complex, much more difficult, because of the peculiar
organization of her victim. The honours are on her side again when we
consider the delicacy of the result obtained. Her caterpillar is not a
corpse, like the Ox whose spinal cord is cut; it is alive, but
incapable of movement. The insect here is man’s superior in all
respects.
Now how did the butcher of our parts and the desnucador of the pampas
light upon the idea of plunging a knife into the seat of the marrow, in
order to produce the sudden death of a colossus which would never
suffer its throat to be cut without first offering a dangerous
resistance? Outside those in the trade and men of science, nobody knows
or suspects the lightning result of that particular wound; we are
almost all in the same state of ignorance on this subject in which I
myself was when my childish curiosity drew me into the killing-shed.
The desnucador and the butcher have learnt their craft from the
teachings of tradition and example: they have had masters; and these
were brought up in the school of other masters, harking back by a chain
of linked traditions to him who, served, no doubt, by some hazard of
the chase, first realized the tremendous effects of a wound in the nape
of the neck. Who shall tell us that a pointed flint-stone, driven by
accident into the spinal marrow of the Reindeer or the Mammoth, did not
rouse the attention of the desnucador’s forerunner? A casual incident
furnished the original idea; observation confirmed it; reflection
matured it; tradition preserved it; example disseminated it. After
that, the same transmission-current. For generation might follow
generation in vain: deprived of masters, the desnucador’s descendants
would return to the primitive state of ignorance. Heredity does not
hand down the art of killing by severing the spinal marrow: no man is
born a cattle-slayer by the desnucador’s method.
Now here is the Ammophila, a slayer of caterpillars by a far more
cunning method. Where are the professors of the art of stinging? There
are not any. When the Wasp rends her cocoon and issues from
underground, her predecessors have long ceased to live; she herself
will perish without seeing her successors. Once the larder is stocked
and the egg laid, all connection with the offspring ends; this year’s
perfect insect dies while next year’s insect, still in the larval
stage, slumbers below ground in its silken cot. Absolutely nothing,
therefore, is transmitted by practical illustration. The Ammophila is
born a finished desnucador even as we are born feeders at our mother’s
breast. The nurseling uses its suction-pump, the Ammophila her dart,
without ever being taught; and both are past masters of the difficult
art from the first attempt. There we have instinct, the unconscious
impulse that forms an essential part of the conditions of life and is
handed down by heredity in the same way as the rhythmic action of the
heart and lungs.
Let us try, if possible, to trace the Ammophila’s instinct to its
source. We suffer to-day, more than we ever did, from a mania for
explaining what might well be incapable of explanation. There are
some—and their number seems to increase daily—who settle the stupendous
question with magnificent audacity. Give them half-a-dozen cells, a bit
of protoplasm and a diagram for demonstration; and they will account to
you for everything. The organic world, the intellectual and moral
world, everything derives from the original cell, evolving by means of
its own energies. It’s as simple as A B C. Instinct, roused by a chance
action that has proved favourable to the animal, is an acquired habit.
And men argue on this basis, invoking natural selection, heredity, the
struggle for life. I see plenty of big words, but I should prefer a few
small facts. These little facts I have been collecting and catechizing
for nearly forty years; and their replies are not exactly in favour of
current theories.
You tell me that instinct is an acquired habit, that a casual
circumstance, propitious to the animal’s offspring, was the first to
prompt it. Let us look into the thing more closely. If I understand
aright, we must suppose some Ammophila, in a very remote past, to have
accidentally injured her caterpillar’s nervous centres; to have found
herself the gainer by this operation, both as regards herself, in being
released from a struggle not unattended with danger, and as regards her
larva, thus supplied with fresh, living and yet harmless victuals; and
consequently to have endowed her offspring, by heredity, with a natural
tendency to repeat the advantageous device. The maternal legacy did not
benefit all the descendants equally: some were poor hands at the
newborn art of the stiletto; others were adepts. Then came the struggle
for existence, the hateful væ victis! The weak went under, the strong
flourished; and, as age succeeded age, selection by vital competition
changed the fleeting impression of the start into a deep-rooted,
ineffaceable impression, exemplified in the masterly instinct which we
admire in the Wasp to-day.
Well, I avow, in all sincerity, this is asking a little too much of
chance. When the Ammophila first found herself in the presence of her
caterpillar, there was nothing, you would have it, to guide the sting.
The choice was made at random. The pricks were directed at the upper
surface of the captured prey, at the lower surface, at the sides, the
front and the back indiscriminately, according to the fortunes of a
close struggle. The Hive-bee and the Social Wasp sting those points
which they are able to reach, without showing a preference for one part
over the other. That is how the Ammophila must have acted, when still
ignorant of her art.
Now how many points are there in a Grey Worm, above and below?
Mathematical accuracy would answer, an infinity; a few hundreds will
serve our purpose. Of this number, nine or perhaps more have to be
selected; the needle must be inserted there and not elsewhere: a little
higher, a little lower, a little to one side, it would not produce the
desired effect. If the favourable event is a purely accidental result,
how many combinations would be needed to bring it about, how much time
to exhaust all the possible cases? When the difficulty becomes too
pressing, you take refuge behind the mist of the ages; you retreat into
the shadows of the past as far as fancy can carry you; you call upon
time, that factor of which we have so little at our disposal and which,
for this very reason, is so well suited to hide our illusions. Here you
can let yourselves go and lavish the centuries. Suppose we shake up
hundreds of figures, all of different values, in an urn and draw nine
at random. When shall we, in this way, obtain a sequence fixed
beforehand, a sequence that stands alone? The chance is so slight,
answers mathematics, that we may as well put it down as nil and say
that the desired arrangement will never come about. For the Ammophila
of the prehistoric age, the attempt was renewed only at long intervals,
from one year to the next. Then how did this sequence of nine stings at
nine selected points emerge from the urn of chance? When I am driven to
appeal to infinity in time, I am very much afraid of running up against
absurdity.
‘But,’ say you, ‘the insect did not attain its present surgical
dexterity at the outset: it went through experiments, apprenticeships,
varying degrees of skill. There was a weeding-out by natural selection,
eliminating the less expert, retaining the more gifted; and instinct,
as we know it, developed gradually, thanks to the accumulation of
individual capacities, added to those handed down by heredity.’
The argument is erroneous: instinct developed by degrees is flagrantly
impossible in this case. The art of preparing the larva’s provisions
allows of none but masters and suffers no apprentices; the Wasp must
excel in it from the outset or leave the thing alone. Two conditions,
in fact, are absolutely essential: that the insect should be able to
drag home and store a quarry which greatly surpasses it in size and
strength; and that the newly-hatched grub should be able to gnaw
peacefully, in its narrow cell, a live and comparatively enormous prey.
The suppression of all movements in the victim is the only means of
realizing these conditions; and this suppression, to be complete,
requires sundry dagger-thrusts, one in each motor centre. If the
paralysis and the torpor be not sufficient, the Grey Worm will defy the
efforts of the huntress, will struggle desperately on the road and will
not reach the journey’s end; if the immobility be not complete, the
egg, fixed at a given spot on the worm, will perish under the
contortions of the giant. There is no via media, no half-success.
Either the caterpillar is treated according to rule and the Wasp’s
family is perpetuated; or else the victim is only partially paralysed
and the Wasp’s offspring dies in the egg.
Yielding to the inexorable logic of things, we will therefore admit
that the first Hairy Ammophila, after capturing a Grey Worm to feed her
larva, operated on the patient by the exact method in use to-day. She
seized the creature by the skin of the neck, stabbed it underneath,
opposite each of the nerve-centres and, if the monster threatened
further resistance, munched its brain. It must have happened like this;
for, once more, an unskilled murderess, doing her work in a perfunctory
and haphazard fashion, would leave no successor, since the rearing of
the egg would become impossible. Save for the perfection of her
surgical powers, the slayer of fat caterpillars would die out in the
first generation.
Again I hear you say:
‘The Hairy Ammophila, before hunting the Grey Worm, may have picked out
feebler caterpillars and heaped up several in one cell, until they
represented the same bulk of provender as the big prey of to-day. With
puny game, a few thrusts of the needle, perhaps one, would be enough.
Gradually, large-sized prey came to be preferred, as reducing the
number of hunting expeditions. Then, as successive generations went
after bigger game, the dagger-strokes were multiplied, in proportion to
the victim’s power of resistance; and, by degrees, the elementary
instinct of the outset became the highly-developed instinct of our
time.’
To these arguments we may begin by replying that the larva’s change of
diet and the substitution of one morsel for a number are diametrically
opposed to what happens before our eyes. The Hunting Wasp, as we know
her, is extremely loyal to old customs; she has sumptuary laws which
she never transgresses. She who fed on Weevils in her youth puts
Weevils and naught else in her larva’s cell; she who was supplied with
Buprestis-beetles persists in the fare which she has adopted and serves
her larva with Buprestis-beetles. One Sphex must have Crickets; a
second, Grasshoppers; a third, Locusts. Nothing is accepted but these
particular dishes. The Bembex who hunts Gad-flies revels in them and
refuses to do without them, whereas Stizus ruficornis, who fills the
larder with Praying Mantes, scorns any other game. And so with the
rest. They have each their own taste.
It is true that many allow themselves a more varied bill of fare, but
only within the limits of one entomological group: thus the Weevil and
Buprestis hunters prey upon any species proportioned to their strength.
Were the Hairy Ammophila to make a change in her diet, that would be
her case too. Whether small and sundry to each cell or large and
single, the prey would always consist of caterpillars. So far, so good.
But there remains the question of the many replaced by the unit; and I
do not yet know one instance of such an alteration in the Wasp’s
habits. She who stocks the burrow with a single joint never thinks of
heaping up several of smaller size; she who goes on repeated
expeditions to stack a quantity of game in the same cell does not know
how to limit herself to one head by choosing larger meat. The result of
my observations never varies in this regard. The prehistoric Ammophila,
who abandoned her multiplicity of small game for one colossal head, has
nothing to warrant her existence.
If the point were conceded, would the question be advanced? Not in the
least. Let us accept as the initial prey a feeble caterpillar,
paralysed with a single sting. Even then that sting must not be given
at random, else the act would be more harmful than profitable.
Irritated, but not subdued by the wound, the animal would but become
more dangerous. The dart must strike a nerve-centre, probably in the
middle region of the string of ganglia. This, at any rate, is how the
present-day Ammophilæ seem to go to work when they are addicted to the
rape of frail and slender grubs. What chance would the operator have of
striking that one particular point, if her lancet were wielded without
method? The probability is ludicrously remote: it is as one to the
countless number of points whereof the caterpillar’s body is made up.
And yet, according to the theorists, it is on this probability that the
Wasp’s future depends. What an edifice to balance on the point of a
needle!
Let us go on admitting and continue. The desired point is struck; the
prey is duly paralysed; the egg laid on its flank will develop in
safety. Is that enough? It is at most but a half of what is absolutely
necessary. Another egg is indispensable to complete the future couple
and ensure offspring. Therefore, within a few days’, within a few
hours’ interval, a second sting must be given, as successful as the
first. In other words, the impossible has to be repeated, the
impossible raised to the second degree.
Let us not be discouraged yet; let us sound the uttermost depths of the
problem. Here is a Wasp, some precursor, no matter which, of our
Ammophila, who, favoured by chance, has twice and perhaps oftener
succeeded in reducing the prey to that state of inertia which the
rearing of the egg imperatively demands. She does not know, does not
suspect that she inserted her sting opposite a nerve-centre rather than
elsewhere. As there was nothing to prompt her choice, she acted at
random. Nevertheless, if we are to take the theory of instinct
seriously, we shall have to admit that this fortuitous action, though a
matter of indifference to the insect, left a lasting trace and made so
great an impression that, henceforth, the cunning stratagem which
produces paralysis by attacking the nervous centres is transmissible by
heredity. The Ammophila’s successors, by some prodigious privilege,
will inherit what the mother did not possess. They will know by
instinct the point or points towards which the sting must be directed;
for, if they were still in the prentice stage, if they and their
successors had to risk the chance that accident would tend gradually to
strengthen the nascent impulse, they would be going back to the
likelihood so near allied to nil; they would go back to it year by
year, for centuries to come; and yet the one and only favourable chance
would have to be always recurring. I find it very difficult to believe
in a habit acquired by this prolonged repetition of incidents whereof
not one can take place without excluding so many contrary chances. It
is a simple matter of arithmetic to show the number of absurdities
against which the theorists rush headlong.
Nor is this all. We should have to ask ourselves how casual actions, to
which the insect was not predisposed by nature, can become the source
of a hereditary transmissible habit. We should look upon a man as a
sorry wag who came to us and said that the descendant of the desnucador
knows the art of slaughtering cattle from A to Z merely through being
the son of his father, without the aid of precept or example. The
father does not use his blade just once or twice, by accident; he
operates every day and scores of times a day; he goes to work with
reflection. It is his business. Does this lifelong practice create a
transmissible habit? Are the sons, the grandsons, the great-grandsons
any the wiser, without instruction? No, the thing has to start afresh
each time. Man is not predisposed by nature to this butchery.
If, on her side, the Wasp excels in her art, it is because she is born
to follow it, because she is endowed not only with tools, but also with
the knack of using them. And this gift is original, perfect from the
outset: the past has added nothing to it, the future will add nothing
to it. As it was, so it is and will be. If you see in it naught but an
acquired habit, which heredity hands down and improves, at least
explain to us why man, who represents the highest stage in the
evolution of your primitive plasma, is deprived of the like privilege.
A paltry insect bequeaths its skill to its offspring; and man cannot.
What an immense advantage it would be to humanity if we were less
liable to see the worker succeeded by the idler, the man of talent by
the idiot! Ah, why has not protoplasm, evolving by its own energy from
one being into another, reserved until it came to us a little of that
wonderful power which it has bestowed so lavishly upon the insects! The
answer is that apparently, in this world, cellular evolution is not
everything.
For these among many other reasons, I reject the modern theory of
instinct. I see in it no more than an ingenious game in which the
armchair naturalist, the man who shapes the world according to his
whim, is able to take delight, but in which the observer, the man
grappling with reality, fails to find a serious explanation of anything
whatsoever that he sees. In my own surroundings, I notice that those
who are most positive in the matter of these difficult questions are
those who have seen the least. If they have seen nothing at all, they
go to the length of rashness. The others, the timid ones, know more or
less what they are talking about. And is it not the same outside my
modest environment?
APPENDIX
The following Wasps appear to me to be new to our fauna. I give a
description of each of them.
A
CERCERIS ANTONIÆ—H. FAB.
Length, 16 to 18 millimetres. [56] Black, thickly and deeply spotted.
Shield, raised like a nose, that is to say, forming a convex
projection, broad at the base, pointed at the tip and resembling one
half of a cone divided lengthwise. Prominent crest between the antennæ.
A yellow streak above the crest, yellow cheeks and a large yellow spot
behind each eye. Yellow shield, with black dot. Mandibles, iron-yellow,
with black tips. First four or five joints of the antennæ, iron-yellow;
the rest brown.
Two dots on the prothorax, the wing-scales and the postscutellum
yellow. First segment of the abdomen has two round spots. The next four
segments have on their hinder edge a yellow band cut deeply into the
form of a triangle, or even broken right off; and this is more
noticeable in the less distant segments.
Under-part of the body, black. Legs, iron-yellow all through. Wings,
slightly bronzed at the tip.
The above is a description of the female. The male is unknown to me.
In colouring, this species approaches Cerceris labiata, from which it
differs more particularly by the shape of the shield and by its size,
which is much larger. Observed near Avignon in July.
I dedicate this species to my daughter Antonia, whose assistance has
often been of great value to me in my entomological researches.
B
CERCERIS JULII.—H. FAB.
Length, 7 to 9 millimetres. [57] Black, thickly and deeply spotted.
Shield, flat. Face covered with a fine silvery down. A narrow yellow
band on either side on the inner edge of the eyes. Mandibles, yellow,
with brown tips. Antennæ, black above, pale russet below; lower surface
of their basilar joints, yellow.
On the prothorax two small yellow dots, some distance apart; yellow
wing-scales and postscutellum. A yellow band on the third segment of
the abdomen and another on the fifth segment; these two bands are
deeply hollowed on the fore-edge, the first into a semicircle, the
second into a triangle.
Under-part of the body, entirely black. Black hips; thighs of the
hind-legs, all black; those of the two front pairs, black at the root
and yellow at the end. Legs and tarsi, yellow. Wings slightly
smoke-coloured.
Female.
Varieties: 1. Prothorax without yellow dots. 2. Two small yellow dots
on the second segment of the abdomen. 3. Wider yellow band on the inner
side of the eyes. 4. Front of shield edged yellow.
The male is unknown to me.
This Cerceris, the smallest in my district, feeds her larvæ on very
small-sized Weevils, Bruchus granarius and Apion gravidum. Observed
near Carpentras, where she builds her nest in September, in the soft
sandstone locally known as safre.
C
BEMBEX JULII.—H. FAB.
Length, 18 to 20 millimetres. [58] Black, with bristling whitish hairs
on the head, the thorax and the base of the first segment of the
abdomen. Long upper lip, yellow. Ridge-shaped shield, forming a sort of
trihedral angle, of which one side, that of the fore-edge, is all
yellow, while each of the two others is marked with a large rectangular
black patch, touching the adjacent one, so that the two together form a
chevron; these two patches and also the cheeks are covered with a fine
silvery down. Cheeks and a median line between the antennæ, yellow. The
back rim of the eyes has a long yellow border. Yellow mandibles, brown
at the tips. First two joints of the antennæ, yellow underneath, black
above; the others, yellow.
Prothorax, black, with its sides and dorsal division yellow.
Mesothorax, black; the callous dot and a small dot on either side,
above the base of the intermediate legs, yellow. Metathorax, black,
with two yellow spots behind and a larger one, on either side, above
the base of the hind-legs. The first two spots are sometimes missing.
Abdomen, brilliant black above and bare, except at the base of the
first segment, which bristles with whitish hairs. All the segments have
a wavy transversal band, wider at the sides than in the middle and
nearer to the hinder edge as the segment is farther back. On the fifth
segment the yellow band touches the hinder edge. Anal segment, yellow,
black at the root, covered all over the dorsal surface with rusty-red
papillæ, forming a base for bristles. A row of similar bristle-bearing
protuberances occupies also the hinder edge of the fifth segment.
Underneath, the abdomen is brilliant black, with a triangular yellow
patch on either side of the four intermediary segments.
Black hips; thighs, yellow in front, black behind; yellow legs and
tarsi. Transparent wings.
In the male the chevron mark on the shield is narrower, or even
entirely absent, in which case the face is all yellow. The bands on the
abdomen are a very pale yellow, almost white. The sixth segment has a
band like those which come before, but shorter and often reduced to two
dots. The second segment has underneath it a longitudinal carina,
raised and spine-shaped at the back. Lastly, the anal segment carries
below it a rather thick angular projection. The rest is the same as in
the female.
This Wasp is very much like Bembex rostrata in size and in the
arrangement of the black and yellow. The chief differences lie in the
following characteristics: the shield of Bembex Julii forms a trihedral
angle, whereas it is rounded and convex in the other Bembex. It also
has at its base a broad, chevron-shaped black band, formed of two
rectangular patches joined together and powdered with a silvery down,
which is very brilliant in a suitable light. The upper surface of the
anal segment bristles with papillæ and reddish hairs, as does the
hinder edge of the fifth segment. Lastly, the mandibles are stained
black at the tips only, whereas the base also is black in Bembex
rostrata. Their habits are equally dissimilar. Bembex rostrata hunts
Gad-flies mainly; Bembex Julii never preys on big Flies but attacks
smaller ones of greatly varying species.
Jules’ Bembex is frequent in the sandy soil of Les Angles, round about
Avignon and on the hill at Orange.
D
AMMOPHILA JULII.—H. FAB.
Length, 16 to 22 millimetres. [59] Abdominal petiole consisting of the
first segment and half the second. Third cubital narrowed towards the
radial. Head, black, with silvery down on the face. Antennæ, black.
Thorax, black, with transverse stripes on its three segments, darker on
the prothorax and the mesothorax. Two patches on the sides and one
behind either side of the metathorax, covered with silvery down.
Abdomen, bare and shiny. First segment, black. Second segment, red in
the part narrowed into a petiole and in the widened part. Third
segment, all red. The others, a beautiful, metallic indigo-blue. Legs,
black, with silvery down on the hips. Wings, slightly reddish. Builds
her nest in October and stocks each cell with two medium-sized
caterpillars.
Is nearly related to Ammophila holosericea, being of the same size, but
differs markedly in the colour of her legs, which are all black, in her
head and thorax, which are much less hairy, and in the transverse
stripes on the three segments of the thorax.
I wish these three Wasps to bear the name of my son Jules, to whom I
dedicate them.
Dear Jules, snatched at such an early age from your passionate love of
flowers and insects, you were my fellow-worker; nothing escaped your
clear-sighted glance; I was to write this book for you, to whom its
stories gave such delight; and you yourself were to continue it one
day. Alas, you went to a happier home, knowing nothing of the book but
its first lines! May your name at least figure in it, borne by some of
those industrious and beautiful Wasps whom you loved so well!
J. H. F.
Orange, 3 April 1879.
NOTES
[1] Léon Dufour (1780–1865) was an army surgeon who served with
distinction in several campaigns and subsequently practised as a doctor
in the Landes. He attained great eminence as a naturalist. Cf. The Life
of the Spider, by J. Henri Fabre, translated by Alexander Teixeira de
Mattos, chap, i.—Translator’s Note.
[2] For the complete monograph, cf. Annales des sciences naturelles:
Series II., vol. xv.—Author’s Note.
[3] The 450 Buprestes unearthed belong to the following species:
Buprestis octoguttata; B. fasciata; B. pruni; B. tarda; B. biguttata;
B. micans; B. flavomaculata; B. chrysostigma; and B.
novemmaculata.—Author’s Note.
[4] Pierre André Latreille (1762–1833), a French naturalist who was one
of the founders of entomological science.—Translator’s Note.
[5] The Beetle known to Fabre as Sphenoptera geminata, Uliger, is now
considered identical with S. lineola, Herbst, which was known many
years earlier.—Translator’s Note.
[6] ·528 oz. av.—Translator’s Note.
[7] ·88 oz. av.—Translator’s Note.
[8] For a description of this species, which is new to entomology, see
the Appendix.—Author’s Note.
[9] Marie Jean Pierre Flourens (1794–1867), the celebrated French
physiologist, appointed perpetual secretary of the Academy of Science
in 1833 and a member of the French Academy.—Translator’s Note.
[10] François Magendie (1783–1855), professor of anatomy in the Collège
de France, noted for his experiments on the physiology of the
nerves.—Translator’s Note.
[11] Claude Bernard (1813–1878), another distinguished French
physiologist and perhaps the most famous representative of experimental
science in the nineteenth century.—Translator’s Note.
[12] Annales des sciences naturelles, Series III., vol. v.—Author’s
Note.
[13] For the Sacred Scarab, or Sacred Beetle, cf. Insect Life, by J. H.
Fabre, translated by the author of Mademoiselle Mori: chaps. i. and
ii.; and The Life and Love of the Insect, by J. Henri Fabre, translated
by Alexander Teixeira de Mattos: chaps, i. to iv.—Translator’s Note.
[14] For Philanthus Apivorus, the Bee-eating Wasp, cf. Social Life in
the Insect World, by J. H. Fabre, translated by Bernard Miall: chap.
xiii.—Translator’s Note.
[15] Cf. The Life and Love of the Insect: chap. xi.—Translator’s Note.
[16] Cf. The Life and Love of the Insect: chap. xii.—Translators Note.
[17] ·117 to ·156 inch.—Translator’s Note.
[18] A species of Green Grasshopper.—Translator’s Note.
[19] Nearly half an inch.—Translator’s Note.
[20] ·975 to 1·17 inch.—Translator’s Note.
[21] ·195 to ·234 inch.—Translator’s Note.
[22] 1·05 × ·35 inch.—Translator’s Note.
[23] Cf. Social Life in the Insect World: chaps. i. to iv.—Translator’s
Note.
[24] Cf. Social Life in the Insect World: chaps. v. to
vii.—Translator’s Note.
[25] The order of insects including Earwigs, Cockroaches, Mantes,
Crickets, Locusts and Grasshoppers.—Translator’s Note.
[26] Amédée Comte Lepeletier de Saint-Fargeau (1769–circa 1850), author
of an Histoire naturelle des insectes (1836–1846) and of the volume on
insects in the Encyclopédie méthodique. He was a younger brother of
Louis Michel and Félix Lepeletier de Saint-Fargeau, the members of the
Convention.—Translator’s Note.
[27] Jean Théodore Lacordaire (1801–1870), professor at the university
of Liège from 1835, author of Les Genera des coléoptères, in twelve
volumes, and of the Introduction à l’entomologie quoted above
(1837–1839).—Translator’s Note.
[28] Erasmus Darwin (1731–1802), the poet and naturalist, grandfather
of Charles Robert Darwin. The book from which the above passage is
quoted is Zoonomia, or, The Laws of Organic Life (1794–1796); but the
reader will note that the author withdraws these comments in a later
essay (cf. The Mason-bees, by J. Henri Fabre, translated by Alexander
Teixeira de Mattos: chap. vii.), where he explains that they are due to
a misquotation or mistranslation made by Lacordaire, who wrote ‘a
Sphex’ where Darwin, as his grandson pointed out to Fabre, had written
‘a Wasp,’ meaning the Common or Social Wasp. It was open to me to
suppress this part of the chapter; but, in that case, there would have
been so little left of the original and so small an excuse for the
title that I might as readily have suppressed the whole chapter, a
liberty which I did not feel justified in taking. Besides, the footnote
to the aforementioned chapter of The Mason-bees, which precedes the
present volume in the English edition, makes sufficient amends for any
injury done to the elder Darwin’s reputation here.—Translator’s Note.
[29] ‘The busy bees, with a soft murmuring strain,
Invite to gentle sleep the labouring swain.’—
Pastorals, i., Dryden’s translation.
[30] Cf. p. 43 n. Flourens’ Expériences sur le système nerveux were
first published in 1825.—Translator’s Note.
[31] ·039 inch.—Translator’s Note.
[32] The caterpillars of the Geometræ, or Geometrid Moths, are called
also Inchworms, Spanworms and Surveyors.—Translator’s Note.
[33] Cf. The Life of the Fly, by J. Henri Fabre, translated by
Alexander Teixeira de Mattos: chap. ix.—Translator’s Note.
[34] About ·08 inch.—Translator’s Note.
[35] For a description of this new species, see the Appendix to the
present volume.—Author’s Note.
[36] Or Flesh-fly. Cf. The Life of the Fly: chap. x.—Translator’s Note.
[37] The Bluebottle.—Translator’s Note.
[38] The Common House-fly.—Translator’s Note.
[39] Cf. The Life of the Fly: chaps. ii. and iv.—Translator’s Note.
[40] For other essays on the homing of insects, cf. The Mason-bees:
chaps. ii. to vi.—Translator’s Note.
[41] ·061 cubic inch.—Translator’s Note.
[42] 61 cubic inches.—Translator’s Note.
[43] The piece of waste ground on which the author used to study his
insects in their natural state. Cf. The Life of the Fly: chap.
i.—Translator’s Note.
[44] Gun-flints.—Author’s Note.
[45] The local expression.—Author’s Note.
[46] Burying-beetles.—Translator’s Note.
[47] Carrion-beetles.—Translator’s Note.
[48] Mimic-beetles.—Translator’s Note.
[49] Bacon-beetles.—Translator’s Note.
[50] The Horseshoe Bat.—Translator’s Note.
[51] Lazaro Spallanzani (1729–1799), the great Italian
naturalist.—Translator’s Note.
[52] ‘This night, at least, with me forget your care;
Chestnuts and curds and cream shall be your fare
The carpet-ground shall be with leaves o’erspread
And boughs shall weave a covering for your head.’—
Pastorals, book i., Dryden’s translation.
[53] Louis Racine (1692–1763), son of Jean Racine.—Translator’s Note.
[54] ... and even in the mire,
The insect, of its worth assured, once and again
Ventures to challenge us to make good our disdain.
[55] L. Couty, in the Revue scientifique, 6 August 1881.—Author’s Note.
[56] ⅝ to ¾ inch.—Translator’s Note.
[57] ¼ to ⅓ inch.—Translator’s Note.
[58] ¾ to ⅞ inch.—Translator’s Note.
[59] ·62 to ·86 inch.—Translator’s Note.