The Life of the Fly
by
J. Henri Fabre
Part 1 out of 5
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THE LIFE OF THE FLY:
With Which are Interspersed Some Chapters of Autobiography
By J. Henri Fabre
Translated by Alexander Teixeira de Mattos
Fellow of the Zoological Society of London
CONTENTS
TRANSLATOR'S NOTE
I THE HARMAS
II THE ANTHRAX
III ANOTHER PROBER (PERFORATOR)
IV LARVAL DIMORPHISM
V HEREDITY
VI MY SCHOOLING
VII THE POND
VIII THE CADDIS WORM
IX THE GREENBOTTLES
X THE GRAY FLESH FLIES
XI THE BUMBLEBEE FLY
XII MATHEMATICAL MEMORIES: NEWTON'S BINOMIAL THEOREM
XIII MATHEMATICAL MEMORIES: MY LITTLE TABLE
XIV THE BLUEBOTTLE: THE LAYING
XV THE BLUEBOTTLE: THE GRUB
XVI A PARASITE OF THE MAGGOT
XVII RECOLLECTIONS OF CHILDHOOD
XVIII INSECTS AND MUSHROOMS
XIX A MEMORABLE LESSON
XX INDUSTRIAL CHEMISTRY
TRANSLATOR'S NOTE
The present volume contains all the essays on flies, or Diptera,
from the Souvenirs entomologiques, to which I have added, in order
to make the dimensions uniform with those of the other volumes of
the series, the purely autobiographical essays comprised in the
Souvenirs. These essays, though they have no bearing upon the
life of the fly, are among the most interesting that Henri Fabre
has written and will, I am persuaded, make a special appeal to the
reader. The chapter entitled The Caddis Worm has been included
as following directly upon The Pond.
Since publishing The Life of the Spider, I was much struck by a
passage in Dr. Chalmers Mitchell's stimulating work, The Childhood
of Animals, in which the secretary of the Zoological Society of
London says: 'I have attempted to avoid the use of terms familiar
only to students of zoology and to refrain from anatomical detail,
but at the same time to refrain from the irritating habit assuming
that my readers have no knowledge, no dictionaries and no other
books.'
I began to wonder whether I had gone too far in simplifying the
terminology of the Fabre essays and in appending explanatory
footnotes to the inevitable number of outlandish names of insects.
But my doubts vanished when I thought upon Fabre's own words in
the first chapter of this book: 'If I write for men of learning,
for philosophers...I write above all things for the young. I want
to make them love the natural story which you make them hate; and
that is why, while keeping strictly to the domain of truth, I
avoid your scientific prose, which too often, alas, seems borrowed
from some Iroquois idiom!'
And I can but apologize if I have been too lavish with my notes to
this chapter in particular, which introduces to us, as in a sort
of litany, a multitude of the insects studied by the author. For
the rest, I have continued my system of references to the earlier
Fabre books, whether translated by myself or others. Of the
following essays, The Harmas has appeared, under another title, in
The Daily Mail; The Pond, Industrial Chemistry and the two
Chapters on the bluebottle in The English Review; and The Harmas,
The Pond and Industrial Chemistry in the New York Bookman. The
others are new to England and America, unless any of them should
be issued in newspapers or magazines between this date and the
publication of the book.
I wish once more to thank Miss Frances Rodwell for her assistance
in the details of my work and in the verification of the many
references; and my thanks are also due to Mr. Edward Cahen, who
has been good enough to revise the two chemistry chapters for me,
and to Mr. W. S. Graff Baker, who has performed the same kindly
task towards the two chapters entitled Mathematical Memories.
-- Alexander Teixeira de Mattos. Chelsea, 8 July, 1913.
[Recorder's Note: Most Translator's Footnotes have been omitted
from this text, but some of his references to localities and
insect names are included in brackets. I apologize to English
readers for changes to American spelling.]
CHAPTER I THE HARMAS
This is what I wished for, hoc erat in votis: a bit of land, oh,
not so very large, but fenced in, to avoid the drawbacks of a
public way; an abandoned, barren, sun scorched bit of land,
favored by thistles and by wasps and bees. Here, without fear of
being troubled by the passersby, I could consult the Ammophila and
the Sphex [two digger or hunting wasps] and engage in that
difficult conversation whose questions and answers have experiment
for their language; here, without distant expeditions that take up
my time, without tiring rambles that strain my nerves, I could
contrive my plans of attack, lay my ambushes and watch their
effects at every hour of the day. Hoc erat in votis. Yes, this
was my wish, my dream, always cherished, always vanishing into the
mists of the future.
And it is no easy matter to acquire a laboratory in the open
fields, when harassed by a terrible anxiety about one's daily
bread. For forty years have I fought, with steadfast courage,
against the paltry plagues of life; and the long-wished-for
laboratory has come at last. What it has cost me in perseverance
and relentless work I will not try to say. It has come; and, with
it--a more serious condition--perhaps a little leisure. I say
perhaps, for my leg is still hampered with a few links of the
convict's chain.
The wish is realized. It is a little late, O my pretty insects! I
greatly fear that the peach is offered to me when I am beginning
to have no teeth wherewith to eat it. Yes, it is a little late:
the wide horizons of the outset have shrunk into a low and
stifling canopy, more and more straitened day by day. Regretting
nothing in the past, save those whom I have lost; regretting
nothing, not even my first youth; hoping nothing either, I have
reached the point at which, worn out by the experience of things,
we ask ourselves if life be worth the living.
Amid the ruins that surround me, one strip of wall remains
standing, immovable upon its solid base: my passion for scientific
truth. Is that enough, O my busy insects, to enable me to add yet
a few seemly pages to your history? Will my strength not cheat my
good intentions? Why, indeed, did I forsake you so long? Friends
have reproached me for it. Ah, tell them, tell those friends, who
are yours as well as mine, tell them that it was not forgetfulness
on my part, not weariness, nor neglect: I thought of you; I was
convinced that the Cerceris [a digger wasp] cave had more fair
secrets to reveal to us, that the chase of the Sphex held fresh
surprises in store. But time failed me; I was alone, deserted,
struggling against misfortune. Before philosophizing, one had to
live. Tell them that; and they will pardon me.
Others again have reproached me with my style, which has not the
solemnity, nay, better, the dryness of the schools. They fear
lest a page that is read without fatigue should not always be the
expression of the truth. Were I to take their word for it, we are
profound only on condition of being obscure. Come here, one and
all of you--you, the sting bearers, and you, the wing-cased armor-
clads--take up my defense and bear witness in my favor. Tell of
the intimate terms on which I live with you, of the patience with
which I observe you, of the care with which I record your actions.
Your evidence is unanimous: yes, my pages, though they bristle not
with hollow formulas nor learned smatterings, are the exact
narrative of facts observed, neither more nor less; and whoever
cares to question you in his turn will, obtain the same replies.
And then, my dear insects, if you cannot convince those good
people, because you do not carry the weight of tedium, I, in my
turn, will say to them: 'You rip up the animal and I study it
alive; you turn it into an object of horror and pity, whereas I
cause it to be loved; you labor in a torture chamber and
dissecting room, I make my observations under the blue sky to the
song of the cicadas, you subject cell and protoplasm to chemical
tests, I study instinct in its loftiest manifestations; you pry
into death, I pry into life. And why should I not complete my
thought: the boars have muddied the clear stream; natural history,
youth's glorious study, has, by dint of cellular improvements,
become a hateful and repulsive thing. Well, if I write for men of
learning, for philosophers, who, one day, will try to some extent
to unravel the tough problem of instinct, I write also, I write
above all things for the young. I want to make them love the
natural history which you make them hate; and that is why, while
keeping strictly to the domain of truth, I avoid your scientific
prose, which too often, alas seems borrowed from some Iroquois
idiom."
But this is not my business for the moment: I want to speak of the
bit of land long cherished in my plans to form a laboratory of
living entomology, the bit of land which I have at last obtained
in the solitude of a little village. It is a harmas, the name
given, in this district [the country round Serignan, in Provence],
to an untilled, pebbly expanse abandoned to the vegetation of the
thyme. It is too poor to repay the work of the plow; but the
sheep passes there in spring, when it has chanced to rain and a
little grass shoots up.
My harmas, however, because of its modicum of red earth swamped by
a huge mass of stones, has received a rough first attempt at
cultivation: I am told that vines once grew here. And, in fact,
when we dig the ground before planting a few trees, we turn up,
here and there, remains of the precious stock, half carbonized by
time. The three pronged fork, therefore, the only implement of
husbandry that can penetrate such a soil as this, has entered
here; and I am sorry, for the primitive vegetation has
disappeared. No more thyme, no more lavender, no more clumps of
kermes oak, the dwarf oak that forms forests across which we step
by lengthening our stride a little. As these plants, especially
the first two, might be of use to me by offering the Bees and
Wasps a spoil to forage, I am compelled to reinstate them in the
ground whence they were driven by the fork.
What abounds without my mediation is the invaders of any soil that
is first dug up and then left for a long time to its own
resources. We have, in the first rank, the couch grass, that
execrable weed which three years of stubborn warfare have not
succeeded in exterminating. Next, in respect of number, come the
centauries, grim looking one and all, bristling with prickles or
starry halberds. They are the yellow-flowered centaury, the
mountain centaury, the star thistle and the rough centaury: the
first predominates. Here and there, amid their inextricable
confusion, stands, like a chandelier with spreading, orange
flowers for lights, the fierce Spanish oyster plant, whose spikes
are strong as nails. Above it, towers the Illyrian cotton
thistle, whose straight and solitary stalk soars to a height of
three to six feet and ends in large pink tufts. Its armor hardly
yields before that of the oyster plant. Nor must we forget the
lesser thistle tribe, with first of all, the prickly or 'cruel'
thistle, which is so well armed that the plant collector knows not
where to grasp it; next, the spear thistle, with its ample
foliage, ending each of its veins with a spear head; lastly, the
black knapweed, which gathers itself into a spiky knot. In among
these, in long lines armed with hooks, the shoots of the blue
dewberry creep along the ground. To visit the prickly thicket
when the Wasp goes foraging, you must wear boots that come to mid-
leg or else resign yourself to a smarting in the calves. As long
as the ground retains a few remnants of the vernal rains, this
rude vegetation does not lack a certain charm, when the pyramids
of the oyster plant and the slender branches of the cotton thistle
rise above the wide carpet formed by the yellow-flowered centaury
saffron heads; but let the droughts of summer come and we see but
a desolate waste, which the flame of a match would set ablaze from
one end to the other. Such is, or rather was, when I took
possession of it, the Eden of bliss where I mean to live
henceforth alone with the insect. Forty years of desperate
struggle have won it for me.
Eden, I said; and, from the point of view that interests me, the
expression is not out of place. This cursed ground, which no one
would have had at a gift to sow with a pinch of turnip seed, is an
earthly paradise for the bees and wasps. Its mighty growth of
thistles and centauries draws them all to me from everywhere
around. Never, in my insect hunting memories, have I seen so
large a population at a single spot; all the trades have made it
their rallying point. Here come hunters of every kind of game,
builders in clay, weavers of cotton goods, collectors of pieces
cut from a leaf or the petals of a flower, architects in
pasteboard, plasterers mixing mortar, carpenters boring wood,
miners digging underground galleries, workers handling
goldbeater's skin and many more.
Who is this one? An Anthidium [a tailor bee]. She scrapes the
cobwebby stalk of the yellow-flowered centaury and gathers a ball
of wadding which she carries off proudly in the tips of her
mandibles. She will turn it, under ground, into cotton felt
satchels to hold the store of honey and the egg. And these
others, so eager for plunder? They are Megachiles [leaf-cutting
bees], carrying under their bellies their black, white or blood
red reaping brushes. They will leave the thistles to visit the
neighboring shrubs and there cut from the leaves oval pieces which
will be made into a fit receptacle to contain the harvest. And
these, clad in black velvet? They are Chalicodomae [mason bees],
who work with cement and gravel. We could easily find their
masonry on the stones in the harmas. And these noisily buzzing
with a sudden flight? They are the Anthophorae [wild bees], who
live in the old walls and the sunny banks of the neighborhood.
Now come the Osmiae. One stacks her cells in the spiral staircase
of an empty snail shell; another, attacking the pith of a dry bit
of bramble, obtains for her grubs a cylindrical lodging and
divides it into floors by means of partition walls; a third
employs the natural channel of a cut reed; a fourth is a rent-free
tenant of the vacant galleries of some mason bee. Here are the
Macrocerae and the Eucerae, whose males are proudly horned; the
Dasypodae, who carry an ample brush of bristles on their hind legs
for a reaping implement; the Andrenae, so manifold in species; the
slender-bellied Halicti [all wild bees]. I omit a host of others.
If I tried to continue this record of the guests of my thistles,
it would muster almost the whole of the honey yielding tribe. A
learned entomologist of Bordeaux, Professor Perez, to whom I
submit the naming of my prizes, once asked me if I had any special
means of hunting, to send him so many rarities and even novelties.
I am not at all an experienced and, still less, a zealous hunter,
for the insect interests me much more when engaged in its work
than when struck on a pin in a cabinet. The whole secret of my
hunting is reduced to my dense nursery of thistles and centauries.
By a most fortunate chance, with this populous family of honey
gatherers was allied the whole hunting tribe. The builders' men
had distributed here and there in the harmas great mounds of sand
and heaps of stones, with a view to running up some surrounding
walls. The work dragged on slowly; and the materials found
occupants from the first year. The mason bees had chosen the
interstices between the stones as a dormitory where to pass the
night, in serried groups. The powerful eyed lizard, who, when
close pressed, attacks both man and dog, wide mouthed, had
selected a cave wherein to lie in wait for the passing scarab [a
dung beetle also known as the sacred beetle]; the black-eared
chat, garbed like a Dominican, white-frocked with black wings, sat
on the top stone, singing his short rustic lay: his nest, with its
sky blue eggs, must be somewhere in the heap. The little
Dominican disappeared with the loads of stones. I regret him: he
would have been a charming neighbor. The eyed lizard I do not
regret at all.
The sand sheltered a different colony. Here, the Bembeces [digger
wasps] were sweeping the threshold of their burrows, flinging a
curve of dust behind them; the Languedocian Sphex was dragging her
Ephippigera [a green grasshopper] by the antennae; a Stizus [a
hunting wasp] was storing her preserves of Cicadellae
[froghoppers]. To my sorrow, the masons ended by evicting the
sporting tribe; but, should I ever wish to recall it, I have but
to renew the mounds of sand: they will soon all be there.
Hunters that have not disappeared, their homes being different,
are the Ammophilae, whom I see fluttering, one in spring, the
others in autumn, along the garden walks and over the lawns, in
search of a caterpillar; the Pompili [digger or hunting wasp], who
travel alertly, beating their wings and rummaging in every corner
in quest of a spider. The largest of them waylays the Narbonne
Lycosa [known also as the black-bellied tarantula], whose burrow
is not infrequent in the harmas. This burrow is a vertical well,
with a curb of fescue grass intertwined with silk. You can see
the eyes of the mighty Spider gleam at the bottom of the den like
little diamonds, an object of terror to most. What a prey and
what dangerous hunting for the Pompilus! And here, on a hot summer
afternoon, is the Amazon ant, who leaves her barrack rooms in long
battalions and marches far afield to hunt for slaves. We will
follow her in her raids when we find time. Here again, around a
heap of grasses turned to mould, are Scoliae [large hunting wasps]
an inch and a half long, who fly gracefully and dive into the
heap, attracted by a rich prey, the grubs of Lamellicorns,
Orycotes and Ceotoniae [various beetles].
What subjects for study! And there are more to come. The house
was as utterly deserted as the ground. When man was gone and
peace assured, the animal hastily seized on everything. The
warbler took up his abode in the lilac shrubs; the greenfinch
settled in the thick shelter of the cypresses; the sparrow carted
rags and straw under every slate; the Serin finch, whose downy
nest is no bigger than half an apricot, came and chirped in the
plane tree tops; the Scops made a habit of uttering his
monotonous, piping note here, of an evening; the bird of Pallas
Athene, the owl, came hurrying along to hoot and hiss.
In front of the house is a large pond, fed by the aqueduct that
supplies the village pumps with water. Here, from half a mile and
more around, come the frogs and Toads in the lovers' season. The
natterjack, sometimes as large as a plate, with a narrow stripe of
yellow down his back, makes his appointments here to take his
bath; when the evening twilight falls, we see hopping along the
edge the midwife toad, the male, who carries a cluster of eggs,
the size of peppercorns, wrapped round his hindlegs: the genial
paterfamilias has brought his precious packet from afar, to leave
it in the water and afterwards retire under some flat stone,
whence he will emit a sound like a tinkling bell. Lastly, when
not croaking amid the foliage, the tree frogs indulge in the most
graceful dives. And so, in May, as soon as it is dark, the pond
becomes a deafening orchestra: it is impossible to talk at table,
impossible to sleep. We had to remedy this by means perhaps a
little too rigorous. What could we do? He who tries to sleep
and cannot needs becomes ruthless.
Bolder still, the wasp has taken possession of the dwelling house.
On my door sill, in a soil of rubbish, nestles the white-banded
Sphex: when I go indoors, I must be careful not to damage her
burrows, not to tread upon the miner absorbed in her work. It is
quite a quarter of a century since I last saw the saucy cricket
hunter. When I made her acquaintance, I used to visit her at a
few miles' distance: each time, it meant an expedition under the
blazing August sun. Today, I find her at my door; we are intimate
neighbors. The embrasure of the closed window provides an
apartment of a mild temperature for the Pelopaeus [a mason wasp].
The earth-built nest is fixed against the freestone wall. To
enter her home, the spider huntress uses a little hole left open
by accident in the shutters. On the moldings of the Venetian
blinds, a few stray mason bees build their group of cells; inside
the outer shutters, left ajar, a Eumenes [a mason wasp] constructs
her little earthen dome, surmounted by a short, bell-mouthed neck.
The common wasp and the Polistes [a solitary wasp] are my dinner
guests: they visit my table to see if the grapes served are as
ripe as they look.
Here, surely--and the list is far from complete--is a company both
numerous and select, whose conversation will not fail to charm my
solitude, if I succeed in drawing it out. My dear beasts of
former days, my old friends, and others, more recent
acquaintances, all are here, hunting, foraging, building in close
proximity. Besides, should we wish to vary the scene of
observation, the mountain [Ventoux] is but a few hundred steps
away, with its tangle of arbutus, rock roses and arborescent
heather; with its sandy spaces dear to the Bembeces; with its
marly slopes exploited by different wasps and bees. And that is
why, foreseeing these riches, I have abandoned the town for the
village and come to Serignan to weed my turnips and water my
lettuces.
Laboratories are being founded, at great expense, on our Atlantic
and Mediterranean coasts, where people cut up small sea animals,
of but meager interest to us; they spend a fortune on powerful
microscopes, delicate dissecting instruments, engines of capture,
boats, fishing crews, aquariums, to find out how the yolk of an
Annelid's egg is constructed, a question whereof I have never yet
been able to grasp the full importance; and they scorn the little
land animal, which lives in constant touch with us, which provides
universal psychology with documents of inestimable value, which
too often threatens the public wealth by destroying our crops.
When shall we have an entomological laboratory for the study not
of the dead insect, steeped in alcohol, but of the living insect;
a laboratory having for its object the instinct, the habits, the
manner of living, the work, the struggles, the propagation of that
little world, with which agriculture and philosophy have most
seriously to reckon?
To know thoroughly the history of the destroyer of our vines might
perhaps be more important than to know how this or that nerve
fiber of a Cirriped [sea animals with hair-like legs, including
the barnacles and acorn shells] ends; to establish by experiment
the line of demarcation between intellect and instinct; to prove,
by comparing facts in the zoological progression, whether human
reason be an irreducible faculty or not: all this ought surely to
take precedence of the number of joints in a Crustacean's antenna.
These enormous questions would need an army of workers; and we
have not one. The fashion is all for the Mollusk and the
Zoophytes [plant-like sea animals, including starfishes,
jellyfishes, sea anemones and sponges]. The depths of the sea are
explored with many drag nets; the soil which we tread is
consistently disregarded. While waiting for the fashion to
change, I open my harmas laboratory of living entomology; and this
laboratory shall not cost the ratepayers one farthing.
CHAPTER II THE ANTHRAX
I made the acquaintance of the Anthrax in 1855 at Carpentras, at
the time when the life history of the oil beetles was causing me
to search the tall slopes beloved of the Anthophora bees [mason
bees]. Her curious pupae, so powerfully equipped to force an
outlet for the perfect insect incapable of the least effort, those
pupae armed with a multiple plowshare at the fore, a trident at
the rear and rows of harpoons on the back wherewith to rip open
the Osmia bee's cocoon and break through the hard crust of the
hillside, betokened a field that was worth cultivating. The
little that I said about her at the time brought me urgent
entreaties: I was asked for a circumstantial chapter on the
strange fly. The stern necessities of life postponed to an ever
retreating future my beloved investigations, so miserably stifled.
Thirty years have passed; at last, a little leisure is at hand;
and here, in the harmas of my village, with an ardor that has in
no wise grown old, I have resumed my plans of yore, still alive
like the coal smoldering under the ashes. The Anthrax has told me
her secrets, which I in my turn am going to divulge. Would that I
could address all those who cheered me on this path, including
first and foremost the revered Master of the Landes [Leon Dufour].
But the ranks have thinned, many have been promoted to another
world and their disciple lagging behind them can but record, in
memory of those who are no more, the story of the insect clad in
deepest mourning.
In the course of July, let us give a few sideward knocks to the
bracing pebbles and detach the nests of the Chalicodoma of the
Walls [a mason bee] from their supports. Loosened by the shock,
the dome comes off cleanly, all in one piece. Moreover--and this
is a great advantage--the cells come into view wide open on the
base of the exposed nest, for at this point they have no other
wall than the surface of the pebble. In this way, without any
scraping, which would be wearisome work for the operator and
dangerous to the inhabitants of the dome, we have all the cells
before our eyes, together with their contents, consisting of a
silky, amber-yellow cocoon, as delicate and translucent as an
onion peeling. Let us split the dainty wrapper with the scissors,
chamber by chamber, nest by nest. If fortune be at all
propitious, as it always is to the persevering, we shall end by
finding that the cocoons harbor two larvae together, one more or
less faded in appearance, the other fresh and plump. We shall
also find some, no less plentiful, in which the withered larva is
accompanied by a family of little grubs wriggling uneasily around
it.
Examination at once reveals the tragedy that is happening under
the cover of the cocoon. The flacid and faded larva is the mason
bee's. A month ago, in June, having finished its mess of honey,
it wove its silken sheath for a bedchamber wherein to take the
long sleep which is the prelude to the metamorphosis. Bulging
with fat, it is a rich and defenseless morsel for whoever is able
to reach it. Then, in spite of apparently insurmountable
obstacles, the mortar wall and the tent without an opening, the
flesh-eating larvae appeared in the secret retreat and are now
glutting themselves on the sleeper. Three different species take
part in the carnage, often in the same nest, in adjoining cells.
The diversity of shapes informs us of the presence of more than
one enemy; the final stage of the creatures will tell us the names
and qualities of the three invaders.
Forestalling the secrets. of the future for the sake of greater
clearness, I will anticipate the actual facts and come at once to
the results produced. When it is by itself on the body of the
mason bee's larva, the murderous grub belongs either to Anthrax
trifasciata, MEIGEN, or to Leucospis gigas, FAB. But, if numerous
little worms, often a score and more, swarm around the victim,
then it is a Chalcidid's family which we have before us. Each of
these ravagers shall have its biography. Let us begin with the
Anthrax.
And first the grub, as it is after consuming its victim, when it
remains the sole occupant of the mason bee's cocoon. It is a
naked worm, smooth, legless and blind, of a creamy dead white,
each segment a perfect ring, very much curved when at rest, but
with the tendency to become almost straight when disturbed.
Through the diaphanous skin, the lens distinguishes patches of
fat, which are the cause of its characteristic coloring. When
younger, as a tiny grub a few millimeters long, it is streaked
with two different kinds of stains, some white, opaque and of a
creamy tint, others translucent and of the palest amber. The
former come from adipose masses in course of formation; the second
from the nourishing fluid or from the blood which laves those
masses.
Including the head, I count thirteen segments. In the middle of
the body these segments are well marked, being separated by a
slight groove; but in the forepart they are difficult to count.
The head is small and is soft, like the rest of the body, with no
sign of any mouth parts even under the close scrutiny of the lens.
It is a white globule, the size of a tiny pin's head and continued
at the back by a pad a little larger, from which it is separated
by a scarcely appreciable crease. The whole is a sort of nipple
swelling slightly on the upper surface; and its double structure
is so difficult to perceive that at first we take it for the
animal's head alone, though it includes both the head and the
prothorax, or first segment of the thorax.
The mesothorax, or middle segment of the thorax, which is two or
three times larger in diameter, is flattened in front and
separated from the nipple formed by the prothorax and the head by
a deep, narrow, curved fissure. On its front surface are two pale
red stigmata, or respiratory orifices, placed pretty close
together. The metathorax, or last segment of the thorax, is a
little larger still in diameter and protrudes. These abrupt
increases in circumference result in a marked hump, sloping
sharply towards the front. The nipple of which the head forms
part is set at the bottom of this hump.
After the metathorax, the shape becomes regular and cylindrical,
while decreasing slightly in girth in the last two or three
segments. Close to the line of separation of the last two rings,
I am able to distinguish, not without difficulty, two very small
stigmata, just a little darker in color. They belong to the last
segment. In all, four respiratory orifices, two in front and two
behind, as is the rule among Flies. The length of the full sized
larva is 15 to 20 millimeters and its breadth 5 to 6.
Remarkable in the first place by the protuberance of its thorax
and the smallness of its head, the grub of the Anthrax acquires
exceptional interest by its manner of feeding. Let us begin by
observing that, deprived of all, even the most rudimentary walking
apparatus, the animal is absolutely incapable of shifting its
position. If I disturb its rest, it curves and straightens itself
in turns by a series of contractions, it tosses about violently
where it lies, but does not manage to progress. It fidgets and
gets no farther. We shall see later the magnificent problem
raised by this inertness.
For the moment, a most unexpected fact claims all our attention.
I refer to the extreme readiness with which the Anthrax' larva
quits and returns to the Chalicodoma grub on which it is feeding.
After witnessing flesh eating larvae at hundreds and hundreds of
meals, I suddenly find myself confronted with a manner of eating
that bears no relation to anything which I have seen before. I
feel myself in a world that baffles my old experience. Let us
recall the table manners of a larva living on prey, the
Ammophila's for instance, when devouring its caterpillar. A hole
is made in the victim's side; and the head and neck of the
nursling dive deep into the wound, to root luxuriously among the
entrails. There is never a withdrawal from the gnawed belly,
never a recoil to interrupt the feast and to take breath awhile.
The vivacious animal always goes forward, chewing, swallowing,
digesting, until the caterpillar's skin is emptied of its
contents. Once seated at table, it does not budge as long as the
victuals last. To tease it with a straw is not always enough to
induce it to withdraw its head outside the wound; I have to use
violence. When removed by force and then left to its own devices,
the creature hesitates for a long time, stretches itself and
mouths around, without trying to open a passage through a new
wound. It needs the attacking point that has just been abandoned.
If it finds the spot, it makes its way in and resumes the work of
eating; but its future is jeopardized from this time forward, for
the game, now perhaps tackled at inopportune points, is liable to
go bad.
With the Anthrax' grub, there is none of this mangling, none of
this persistent clinging to the entrance wound. I have but to
tease it with the tip of a hair pencil and forthwith it retires;
and the lens reveals no wound at the abandoned spot, no such
effusion of blood as there would be if the skin were perforated.
When its sense of security is restored, the grub once more applies
its pimple head to the fostering larva, at any point, no matter
where; and, so long as my curiosity does not prevent it, keeps
itself fixed there, without the least effort, or the least
perceptible movement that could account for the adhesion. If I
repeat the touch with the pencil, I see the same sudden retreat
and, soon after, the same contact just as readily renewed.
This facility for gripping, quitting and regripping, now here, now
there and always without a wound, the part of the victim whence
the nourishment is drawn tells us of itself that the mouth of the
Anthrax is not armed with mandibular fangs capable of digging into
the skin and tearing it. If the flesh were gashed by any such
pincers, one or two attempts would be necessary before they could
be released or reapplied; besides, each point bitten would display
a lesion. Well, there is nothing of the kind: a conscientious
examination through the magnifying glass shows conclusively that
the skin is intact; the grub glues its mouth to its prey or
withdraws it with an ease that can only be explained by a process
of simple contact. This being so, the Anthrax does not chew its
food as do the other carnivorous grubs; it does not eat, it
inhales.
This method of taking nourishment implies an exceptional apparatus
of the mouth, into which it behooves us to inquire before
continuing. My most powerful magnifying glass at last discovers,
at the center of the pimple head, a small spot of an amber-russet
color; and that is all. For a more exhaustive examination we will
employ the microscope. I cut off the strange pimple with the
scissors, wash it in a drop of water and place it on the object
slide. The mouth now stands revealed as a round spot which, for
hue and for the smallness of its size, may be compared with the
front stigmata. It is a small conical crater, with sides of a
pale yellowish-red and with faint, more or less concentric lines.
At the bottom of this funnel is the opening of the gullet, itself
tinted red in front and promptly spreading into a cone at the
back. There is not the slightest trace of mandibular fangs, of
jaws, of mouth parts for seizing and grinding. Everything is
reduced to the bowl shaped opening, with a delicate lining of
horny texture, as is shown by the amber hue and the concentric
streaks. When I look for some term to designate this digestive
entrance, of which so far I know no other example, I can find only
that of a sucker or cupping glass. Its attack is a mere kiss, but
what a perfidious kiss!
We know the machine; now let us see the working. To facilitate
observation, I shifted the newborn Anthrax grub, together with the
Chalicodoma grub, its wet nurse, from the natal cell into a glass
tube. I was thus able, by employing as many tubes as I wanted, to
follow from start to finish, in all its most intimate details, the
strange repast which I am going to describe.
The worm is fixed by its sucker to any convenient part of the
nurse, plump and fat as butter. It is ready to break off its kiss
suddenly, should anything disquiet it, and to resume it as easily
when tranquillity is restored. No Lamb enjoys greater liberty
with its mother's teat. After three or four days of this contact
of the nurse and nursling, the former, at first replete and
endowed with the glossy skin that is a sign of health, begins to
assume a withered aspect. Her sides fall in, her fresh color
fades, her skin becomes covered with little folds and gives
evidence of an appreciable shrinking in this breast which, instead
of milk, yields fat and blood. A week is hardly past before the
progress of the exhaustion becomes startlingly rapid. The nurse
is flabby and wrinkled, as though borne down by her own weight,
like a very slack object. If I move her from her place, she flops
and sprawls like a half-filled water bottle over the new
supporting plane. But the Anthrax' kiss goes on emptying her:
soon she is but a sort of shriveled lard bag, decreasing from hour
to hour, from which the sucker draws a few last oily drains. At
length, between the twelfth and the fifteenth day, all that
remains of the larva of the mason bee is a white granule, hardly
as large as a pin's head.
This granule is the water bottle drained to the last drop, is the
nurse's breast emptied of all its contents. I soften the meager
remnant in water; then, keeping it still immersed, I blow into it
through an extremely attenuated glass tube. The skin fills out,
distends and resumes the shape of the larva, without there being
an outlet anywhere for the compressed air. It is intact,
therefore; it is free of any perforation, which would be forthwith
revealed under the water by an escape of gas. And so, under the
Anthrax' cupping glass, the oily bottle has been drained by a
simple transpiration through the membrane; the substance of the
nurse grub has been transfused into the body of the nursling by a
process akin to that known in physics as endosmosis. What should
we say to a method of being suckled by the mere application of the
mouth to a teatless breast? What we see here may be compared with
that: without any outlet, the milk of the Chalicodoma grub passes
into the stomach of the Anthrax' larva.
Is it really an instance of endosmosis? Might it not rather be
atmospheric pressure that stimulates the flow of nourishing fluids
and distils them into the Anthrax' cup-shaped mouth, working, in
order to create a vacuum. almost like the suckers of the
Cuttlefish? All this is possible, but I shall refrain from
deciding, preferring to assign a large share to the unknown in
this extraordinary method of nutrition. It ought, I think, to
provide physiologists with a field of research in which new views
on the hydrodynamics of live fluids might well be gleaned; and
this field trenches upon others that would also yield rich
harvests. The brief span of my days compels me to set the problem
without seeking to solve it.
And the second problem is this: the Chalicodoma grub destined to
feed the Anthrax is without a wound of any kind. The mother of
the tiny larva is a feeble Fly deprived of whatsoever weapon
capable of injuring her offspring's prey. Moreover, she is
absolutely powerless to penetrate the mason bee's fortress,
powerless as a fluff of down against a rock. On this point there
is no doubt: the future wet nurse of the Anthrax has not been
paralyzed as are the live provisions collected by the Hunting
Wasps; she has received no bite nor scratch nor contusion of any
sort; she has experienced nothing out of the common: in short, she
is in her normal state. The billeted nursling arrives, we shall
presently see how; he arrives, scarcely visible, almost defying
the scrutiny of the lens; and, having made his preparations, he
installs himself, he, the atom, upon the monstrous nurse, whom he
is to drain to the very husk. And she, not paralyzed by a
preliminary vivisection, endowed with all her normal vitality,
lets him have his way, lets herself be sucked dry, with the utmost
apathy. Not a tremor in her outraged flesh, not a quiver of
resistance. No corpse could show greater indifference to the bite
which it receives.
Ah, but the maggot has chosen the hour of attack with traitorous
cunning! Had it appeared upon the scene earlier, when the larva
was consuming its store of honey, things of a surety would have
gone badly with it. The assaulted one, feeling herself bled to
death by that ravenous kiss, would have protested with much
wriggling of body and grinding of mandibles. The position would
have ceased to be tenable and the intruder would have perished.
But at this hour all danger has disappeared. Enclosed in its
silken tent, the larva is seized with the lethargy that precedes
the metamorphosis. Its condition is not death, but neither is it
life. It is an intermediary condition; it is almost the latent
vitality of grain or egg. Therefore there is no sign of
irritation on the larva's part under the needle with which I stir
it and still less under the sucker of the Anthrax grub, which is
able to drain the affluent breast in perfect safety.
This lack of resistance, induced by the torpor of the
transformation, appears to me necessary, in view of the weakness
of the nursling as it leaves the egg, whenever the mother is
herself incapable of depriving the victim of the power of self
defense. And so the nonparalyzed larvae are attacked during the
period of the nymphosis. We shall soon see other instances of
this.
Motionless though it be, the Chalicodoma grub is none the less
alive. The primrose tint and the glossy skin are unequivocal
signs of health: Were it really dead, it would, in less than
twenty-four hours, turn a dirty brown and, soon after, decompose
into a fluid putrescence. Now here is the marvelous thing: during
the fortnight, roughly, that the Anthrax' meal lasts, the butter
color of the larva, an unfailing symptom of the presence of life,
continues unaltered and does not change into brown, the sign of
putrefaction, until hardly anything remains; and even then the
brown hue is often absent. As a rule, the look of live flesh is
preserved until the final pellet, formed of the skin, the sole
residue, makes its appearance. This pellet is white, with not a
speck of tainted matter, proving that life persists until the body
is reduced to nothing.
We here witness the transfusion of one animal into another, the
change of Chalicodoma substance into Anthrax substance; and, as
long as the transfusion is not complete, as long as the eaten has
not disappeared altogether and become the eater, the ruined
organism fights against destruction. What manner of life is this,
which may be compared with the life of a night light whose
extinction is not accomplished until the last drop of oil has
burnt away? How is any creature able to fight against the final
tragedy of corruption up to the last moment in which a nucleus of
matter remains as the seat of vital energy? The forces of the
living creature are here dissipated not through any disturbance of
the equilibrium of those forces, but for the want of any point of
application for them: the larva dies because materially there is
no more of it.
Can we be in the presence of the diffusive life of the plant, a
life which persists in a fragment? By no means: the grub is a
more delicate organic structure. There is unity between the
several parts; and none of them can be jeopardized without
involving the ruin of the others. If I myself give the larva a
wound, if I bruise it, the whole body very soon turns brown and
begins to rot. It dies and decomposes by the mere prick of a
needle; it keeps alive, or at least preserves the freshness of the
live tissues, so long as it is not entirely emptied by the
Anthrax' sucker. A nothing kills it; an atrocious wasting does
not. No, I fail to understand the problem; and I bequeath it to
others.
All that I can see by way of a glimpse--and even then I put
forward my suspicions with extreme reserve--all that I am
permitted to surmise is reduced to this: the substance of the
sleeping larva as yet has no very definite static existence; it is
like the raw materials collected for a building; it is waiting for
the elaboration that is to make a bee of it. To mould those
shapeless lumps of the future insect, the air, that prime adjuster
of living things, circulates among them, passing through a network
of ducts. To organize them, to direct the placing of them, the
nervous system, the embryo of the animal, distributes its
ramifications over them. Nerve and air duct, therefore, are the
essentials; the rest is so much material in reserve for the
process of the metamorphosis. As long as that material is not
employed, as long as it has not acquired its final equilibrium, it
can grow less and less; and life, though languishing, will
continue all the same on the express condition that the
respiratory organs and the nervous filaments be respected. It is
as it were the flame of the lamp, which, whether full or empty,
continues to give light so long as the wick is soaked in oil.
Nothing but fluids, the plastic materials held in reserve, can be
distilled by the Anthrax' sucker through the unpierced skin of the
grub; no part of the respiratory and nervous systems passes. As
the two essential functions remain unscathed, life goes on until
exhaustion is completed. On the other hand, if I myself injure
the larva, I disturb the nervous or air conducting filaments; and
the bruised part spreads a taint, followed by putrefaction, all
over the body.
I have elsewhere, speaking of the Scolia [a digger wasp] devouring
the Cetonia grub, enlarged upon this refined art of eating which
consists in consuming the prey while killing it only at the last
mouthfuls. The Anthrax has the same requirements as his
competitors who dine off fresh viands. He needs meat of that day,
taken from a single joint that has to last a fortnight without
going bad. His method of consuming reaches the highest level of
art: he does not cut into his prey, he sips it little by little
through his sucker. In this way, any dangerous risk is averted.
Whether he imbibe at this spot or at that, even if he abandon the
sucking process and resume it later, by no accident can he ever
attack that which it is incumbent upon him to respect lest
corruption supervene. The others have a fixed position on the
victim, a place at which their mandibles have to bite and enter.
If they move away from it, if they miss the appointed path, they
imperil their existence. The Anthrax, more highly favored, puts
his mouth where it suits him; he leaves off when he pleases and
when he pleases starts again.
Unless I labor under a delusion, I think that I see the necessity
for this privilege. The egg of the carnivorous burrower is firmly
fixed on the victim at a point which varies considerably, it is
true, according to the nature of the prey, but which is uniform
for the same species of prey; moreover--and this is an important
condition--the point of adhesion of that egg is always the head,
whereas the egg of a bee, of the Osmia, for instance, is fixed to
the mess of honey by the hinder end. When hatched, the new born
Wasp grub has not to choose for itself, at its risk and peril, the
suitable point at which to take the first cut in the quarry
without fear of killing it too quickly: all that it need do is to
bite at the spot where it has just been born. The mother, with
her unfailing instinct, has already made the dangerous choice; she
has stuck her egg on the propitious spot and, by the very act of
doing so, marked out the course for the inexperienced grub to
follow. The tact of ripe age here guides the young larva's
behavior at table.
The conditions are very different in the Anthrax' case. The egg
is not placed upon the victuals, it is not even laid in the mason
bee's cell. This is the natural consequence of the mother's
feeble frame and of her lack of any instrument, such as a probe or
auger, capable of piercing the mortar wall. It is for the newly
hatched grub to make its own way into the dwelling. It enters,
finds itself in the presence of ample provisions, the larva of the
mason bee. Free of its actions, it is at liberty to attack the
prey where it chooses; or rather the attacking point will be
decided at haphazard by the first contact of the mouth in quest of
food. Grant this mouth a set of carving tools, jaws and
mandibles; in short, suppose the grub of the Fly to possess a
manner of eating similar to that of the other carnivorous larvae;
and the nursling is at once threatened with a speedy death. He
will split open his nurse's belly, he will dig without any rule to
guide him, he will bite at random, essentials as well as
accessories; and, from one day to the next, he will set up
gangrene in the violated mass, even as I myself do when I give it
a wound. For the lack of an attacking point prescribed for him at
birth, he will perish on the damaged provisions. His freedom of
action will have killed him.
Certainly, liberty is a noble attribute, even in an insignificant
grub; but it also has its dangers everywhere. The Anthrax escapes
the peril only on the condition of being, so to speak, muzzled.
His mouth is not a fierce forceps that tears asunder; it is a
sucker that exhausts but does not wound. Thus restrained by this
safety appliance, which changes the bite into a kiss, the grub has
fresh victuals until it has finished growing, although it knows
nothing of the rules of methodical consumption at a fixed point
and in a predetermined direction.
The considerations which I have set forth seem to me strictly
logical: the Anthrax, owing to the very fact that he is free to
take his nourishment where he pleases on the body of the fostering
larva, must, for his own protection, be made incapable of opening
his victim's body. I am so utterly convinced of this harmonious
relation between the eater and the eaten that I do not hesitate to
set it up as a principle. I will therefore say this: whenever the
egg of any kind of insect is not fastened to the larva destined
for its food, the young grub, free to select the attacking point
and to change it at will, is as it were muzzled and consumes its
provisions by a sort of suction, without inflicting any
appreciable wound. This restriction is essential to the
maintenance of the victuals in good condition. My principle is
already supported by examples many and various, whose depositions
are all to the same effect. The witnesses include, after the
Anthrax, the Leucospis [a parasitic insect] and his rivals, whose
evidence we shall hear presently; the Ephialtes mediator [an
Ichneumon fly], who feeds, in the dry brambles, on the larva of
the Black Psen [a digger wasp]; the Myodites, that strange, fly-
shaped beetle whose grub consumes the larva of the cockchafer.
All--flies, ichneumon flies and beetles--scrupulously spare their
foster mother; they are careful not to tear her skin, so that the
vessel may keep its liquid good to the last.
The wholesomeness of the victuals is not the only condition
imposed: I find a second, which is no less essential. The
substance of the fostering larva must be sufficiently fluid to
ooze through the unbroken skin under the action of the sucker.
Well, the necessary fluidity is realized as the time of the
metamorphosis draws near. When they wished Medea to restore
Pelias to the vigor of youth, his daughters cut the old king's
body to pieces and boiled it in a cauldron, for there can be no
new existence without a prior dissolution. We must pull down
before we can rebuild; the analysis of death is the first step
towards the synthesis of life. The substance of the grub that is
to be transformed into a bee begins, therefore, by disintegrating
and dissolving into a fluid broth. The materials of the future
insect are obtained by a general recasting. Even as the founder
puts his old bronzes into the melting pot in order afterwards to
cast them in a mould whence the metal will issue in a different
shape, so life liquefies the grub, a mere digesting machine, now
thrown aside, and out of its running matter produces the perfect
insect, bee, butterfly or beetle, the final manifestation of the
living creature.
Let us open a Chalicodoma grub under the microscope, during the
period of torpor. Its contents consists almost entirely of a
liquid broth, in which swim numberless oily globules and a fine
dust of uric acid, a sort of off-throw of the oxidized tissues. A
flowing thing, shapeless and nameless, is all that the animal is,
if we add abundant ramified air ducts, some nervous filaments and,
under the skin, a thin layer of muscular fibers. A condition of
this kind accounts for a fatty transpiration through the skin when
the Anthrax' sucker is at work. At any other time, when the larva
is in the active period or else when the insect has reached the
perfect stage, the firmness of the tissues would resist the
transfusion and the suckling of the Anthrax would become a
difficult matter, or even impossible. In point of fact, I find
the grub of the fly established, in the vast majority of cases, on
the sleeping larva and sometimes, but rarely, on the pupa. Never
do I see it on the vigorous larva eating its honey; and hardly
ever on the insect brought to perfection, as we find it enclosed
in its cell all through the autumn and winter. And we can say the
same of the other grub eaters that drain their victims without
wounding them: all are engaged in their death dealing work during
the period of torpor, when the tissues are fluidified. They empty
their patient, who has become a bag of running grease with a
diffused life; but not one, among those I know, reaches the
Anthrax' perfection in the art of extraction.
Nor can any be compared with the Anthrax as regards the means
brought into play in order to leave the cell. These others, when
they become perfect insects, have implements for sapping and
demolishing, stout mandibles, capable of digging the ground, of
pulling down clay partition walls and even of reducing the mason
bee's tough cement to powder. The Anthrax, in her final form, has
nothing like this. Her mouth is a short, soft proboscis, good at
most for soberly licking the sugary exudations of the flowers; her
slim legs are so feeble that to move a grain of sand were an
excessive task for them, enough to strain every joint; her great,
stiff wings, which must remain full spread, do not allow her to
slip through a narrow passage; her delicate suit of downy velvet,
from which you take the bloom by merely breathing on it, could not
withstand the rough contact of the gallery of a mine. Unable
herself to enter the Mason bee's cell to lay her egg, she cannot
leave it either, when the time comes to free herself and appear in
broad daylight in her wedding dress. The larva, on its side, is
powerless to prepare the way for the coming flight. That buttery
little cylinder, owning no tools but a sucker so flimsy that it
barely arrives at substance and so small that it is almost a
geometrical point, is even weaker than the adult insect, which at
least flies and walks. The Mason bee's cell represents to it a
granite cave. How to get out? The problem would be insoluble to
those two incapables, if nothing else played its part.
Among insects, the nymph, or pupa, the transition stage between
the larval and the adult form, is generally a striking picture of
every weakness of a budding organism. A sort of mummy tight bound
in swaddling clothes, motionless and impassive, it awaits the
resurrection. Its tender tissues flow in every direction; its
limbs, transparent as crystal, are held fixed in their place,
along the side, lest a movement should disturb the exquisite
delicacy of the work in course of accomplishment. Even so, to
secure his recovery, is a broken boned patient held captive in the
surgeon's bandages. Absolute stillness is necessary in both
cases, lest they be crippled or even die.
Well, here, by a strange inversion that confuses all our views on
life, a Cyclopean task is laid upon the nymph of the Anthrax. It
is the nymph that has to toil, to strive, to exhaust itself in
efforts to burst the wall and open the way out. To the embryo
falls the desperate duty, which shows no mercy to the nascent
flesh; to the adult insect the joy of resting in the sun. This
transposition of functions has as its result a well sinker's
equipment in the nymph, an eccentric, complicated equipment which
nothing suggested in the larva and which nothing recalls in the
perfect insect. The set of tools includes an assortment of
plowshares, gimlets, hooks and spears and of other implements that
are not found in our trades nor named in our dictionaries. Let us
do our best to describe the strange piercing gear.
In a fortnight at most, the Anthrax has consumed the Chalicodoma
grub, whereof naught remains but the skin, gathered into a white
granule. By the time that July is nearly over, it becomes rare to
find any nurslings left upon their nurses. From this period until
the following May, nothing fresh happens. The Anthrax retains its
larval shape without any appreciable change and lies motionless in
the mason bee's cocoon, beside the pellet remains. When the fine
days of May arrive, the grub shrivels and casts its skin and the
nymph appears, fully clad in a stout, reddish, horny hide.
The head is round and large, separated from the thorax by a
strangulated furrow, crowned on top and in front with a sort of
diadem of six hard, sharp, black spikes, arranged in a semicircle
whose concave side faces downward. These spikes decrease slightly
in length from the summit to the ends of the arch. Taken
together, they suggest the radial crowns which we see the Roman
emperors of the Decadence wear on the medals. This six-fold
plowshare is the chief excavating tool. Lower down, on the median
line, the instrument is finished off with a separate group of two
small black spikes, placed close together.
The thorax is smooth, the wing cases large, folded under the body
like a scarf and coming almost to the middle of the abdomen. This
has nine segments, of which four, starting with the second, are
armed, on the back, down the middle, with a belt of little horny
arches, pale brown in color, drawn up parallel to one another, set
in the skin by their convex surfaces and finishing at both ends
with a hard, black point. Altogether, the belt thus forms a
double row of little thorns, with a hollow in between. I count
about twenty-five twin-toothed arches to one segment, which gives
a total of two hundred spikes for the four rings thus armed.
The use of this rasp, or grater, is obvious: it gives the nymph a
purchase on the wall of its gallery as the work proceeds. Thus
anchored on a host of points, the stern pioneer is able to hit the
obstacle harder with its diadem of awls. Moreover, to make it
more difficult for the instrument to recoil, long, stiff bristles,
pointing backwards, are scattered here and there among the
climbing belts. There are some besides on the other segments,
both on the ventral and the dorsal surface. On the flanks, they
are thicker and arranged as it were in clusters.
The sixth segment carries a similar belt, but a much less powerful
one, consisting of a single row of unassuming thorns. The belt is
weaker still on the seventh segment; lastly, on the eighth, it is
reduced to a mere rough brown shading. Commencing with the sixth,
the rings decrease in width and the abdomen ends in a cone, the
extremity of which, formed of the ninth segment, constitutes a
weapon of a new kind. It is a sheaf of eight brown spikes. The
last two exceed the others in length and stand out from the group
in a double terminal plowshare.
There is a round air hole in front, on either side of the thorax,
and similar stigmata on the flanks of each of the first seven
abdominal segments. When at rest, the nymph is curved into a bow.
When about to act, it suddenly unbends and straightens itself. It
measures 15 to 20 millimeters long and 4 to 5 millimeters across.
Such is the strange perforating machine that is to prepare an
outlet for the feeble Anthrax through the Mason bee's cement. The
structural details, so difficult to explain in words, may be
summed up as follows: in front, on the forehead, a diadem of
spikes, the ramming and digging tool; behind, a many bladed
plowshare which fits into a socket and allows the pupa to slacken
suddenly in readiness for an attack on the barrier which has to be
demolished; on the back, four climbing belts, or graters, which
keep the animal in position by biting on the walls of the tunnel
with their hundreds of teeth; and, all over the body, long, stiff
bristles, pointing backwards, to prevent falls or recoils.
A similar structure exists in the other species of Anthrax with
slight variations of detail. I will confine myself to one
instance, that of Anthrax sinuata, who thrives at the cost of
Osmia tricornis. Her nymph differs from that of Anthrax
trifasciata, the Anthrax of the mason bee, in possessing less
powerful armor. Its four climbing belts consist of only fifteen
to seventeen double spiked arches, instead of twenty-five; also,
the abdominal segments, from the sixth onwards, are supplied
merely with stiff bristles, without a trace of horny spikes. If
the evolution of the various Anthrax flies were better known to
us, the number of these arches would, I believe, be of great
service to entomology in the differentiation of species. I see it
remaining constant for any given species, with marked variations
between one species and another. But this is not my business: I
merely call the attention of the classifiers to this field of
study and pass on.
About the end of May, the coloring of the nymph, hitherto a light
red, alters greatly and forecasts the coming transformation. The
head, the thorax and the scarf formed by the wings become a
handsome, shiny black. A dark band shows on the back of the four
segments with their two rows of spikes; three spots appear on the
two next rings; the anal armor becomes darker. In this manner we
foresee the black livery of the coming insect. The time has
arrived for the pupa to work at the exit gallery.
I was anxious to see it in action, not under natural conditions,
which would be impracticable, but in a glass tube in which I
confine it between two thick stoppers of sorghum pith. The space
thus marked off is about the same size as the natal cell. The
partitions front and back, although not so stout as the
Chalicodoma's masonry, are nevertheless firm enough not to yield
except to prolonged efforts; on the other hand, the side walls are
smooth and the toothed belts will not be able to grip them: a most
unfavorable condition for the worker. No matter: in the space of
a single day, the pupa pierces the front partition, three quarters
of an inch thick. I see it fixing its double plowshare against
the back partition, arching into a bow and then suddenly releasing
itself and striking the plug in front of it with its barbed
forehead. Under the impact of the spikes, the sorghum slowly
crumbles to pieces. It is slow in coming away; but it comes away
all the same, atom by atom. At long intervals, the method
changes. With its crown of awls driven into the pith, the animal
frets and fidgets, sways on the pivot of its anal armor. The work
of the auger follows that of the pickaxe. Then the blows
recommence, interspersed with periods of rest to recover from the
fatigue. At last, the hole is made. The pupa slips into it, but
does not pass through entirely: the head and thorax appear
outside; the abdomen remains held in the gallery.
The glass cell, with its lack of supports at the side, has
certainly perplexed my subject, which does not seem to have made
use of all its methods. The hole through the sorghum is wide and
irregular; it is a clumsy breach and not a gallery. When made
through the mason bee's walls, it is cylindrical, fairly neat and
exactly of the animal's diameter. So I hope that, under natural
conditions, the pupa does not give quite so many blows with the
pickaxe and prefers to work with the drill.
Narrowness and evenness in the exit tunnel are necessary to it.
It always remains half caught in it and even pretty securely fixed
by the graters on its back. Only the head and thorax emerge into
the outer air. This is a last precaution for the final
deliverance. A fixed support is, in fact, indispensable to the
Anthrax for issuing from her horny sheath, unfurling her great
wings and extricating her slender legs from their scabbards. All
this very delicate work would be endangered by any lack of
steadiness.
The pupa, therefore, remains fixed by the graters of its back in
the narrow exit gallery and thus supplies the stable equilibrium
essential to the new birth. All is ready. It is time now for the
great act. A transversal cleft makes its appearance on the
forehead, at the bottom of the perforating diadem; a second, but
longitudinal slit divides the skull in two and extends down the
thorax. Through this cross-shaped opening, the Anthrax suddenly
appears, all moist with the humors of life's laboratory. She
steadies herself upon her trembling legs, dries her wings and
takes to flight, leaving at the window of the cell her nymphal
slough, which keeps intact for a very long period. The sand-
colored fly has five or six weeks before her, wherein to explore
the clay nests amid the thyme and to take her small share of the
joys of life. In July, we shall see her once more, busy this time
with the entrance into the cell, which is even stranger than the
exit.
CHAPTER III ANOTHER PROBER (PERFORATOR)
What can he be called, this creature whose style and title I dare
not inscribe at the head of the chapter? His name is
Monodontomerus cupreus, SM. Just try it, for fun: Mo-no-don-to-
me-rus. What a gorgeous mouthful! What an idea it gives one of
some beast of the Apocalypse! We think, when we pronounce the
word, of the prehistoric monsters: the mastodon, the mammoth, the
ponderous megatherium. Well, we are misled by the scientific
label: we have to do with a very paltry insect, smaller than the
common gnat.
There are good people like that, only too happy to serve science
with resounding appellations that might come from Timbuktu; they
cannot name you a midge without striking terror into you. O ye
wise and revered ones, ye christeners of animals, I am willing, in
my study, to make use--but not undue use--of your harsh
terminology, with its conglomeration of syllables; but there is a
danger of their leaving the sanctum and appearing before the
public, which is always ready to show its lack of deference for
terms that do not respect its ears. I, wishing to speak like
everybody else, so that I may be understood by all, and persuaded
that science has no need of this Brobdignagian jargon, make a
point of avoiding technical nomenclature when it becomes too
barbarous, when it threatens to lumber the page the moment my pen
attempts it. And so I abandon Monodontomerus.
It is a puny little insect, almost as tiny as the midges whom we
see eddying in a ray of sunshine at the end of autumn. Its dress
is golden bronze; its eyes are coral red. It carries a naked
sword, that is to say, the sheath of its drill stands out slantwise
at the tip of its belly, instead of lying in a hollow groove along
the back, as it does with the Leucospis. This scabbard holds the
latter half of the inoculating filament, which extends below the
animal to the base of the abdomen. In short, its utensil is that
of the Leucospis, with this difference, that its lower half sticks
out like a rapier.
This mite that bears a sword upon her rump is yet another
persecutor of the mason bees and not one of the least formidable.
She exploits their nests at the same time as the Leucospis. I see
her, like the Leucospis, slowly explore the ground with her
antennae; I see her, like the Leucospis, bravely drive her dagger
into the stone wall. More taken up with her work, less conscious
perhaps of danger, she pays no heed to the man who is observing her
so closely. Where the Leucospis flies, she does not budge. So
great is her assurance that she comes right into my study, to my
work table, and disputes my ownership of the nests whose occupants
I am examining. She operates under my lens, she operates just
beside my forceps. What risk does she run? What can one do to a
thing so very small? She is so certain of her safety that I can
take the Mason's nest in my hand, move it, put it down and take it
up again without the insect's raising any objection: it continues
its work even when my magnifying glass is placed over it.
One of these heroines has come to inspect a nest of the
Chalicodoma of the Walls, most of whose cells are occupied by the
numerous cocoons of a parasite, the Stelis. The contents of these
cells, which have been partially ripped up to satisfy my
curiosity, are very much exposed to view. The windfall appears to
be appreciated, for I see the dwarf ferret about from cell to cell
for four days on end, see her choose her cocoon and insert her awl
in the most approved fashion. I thus learn that sight, although
an indispensable guide in searching, does not decide upon the
proper spot for the operation. Here is an insect exploring not
the stony exterior of the mason's dwelling, but the surface of
cocoons woven of silk. The explorer has never found herself
placed in such circumstances, nor has any of her race before her,
every cocoon, under normal conditions, being protected by a
surrounding wall. No matter: despite the profound difference in
the surfaces, the insect does not waver. Warned by a special
sense, an undecipherable riddle to ourselves, it knows that the
object of its search lies hidden under this unfamiliar casing.
The sense of smell has already been shown to be out of the
question; that of sight is now eliminated in its turn.
That she should bore through the cocoons of the Stelis, a parasite
of the mason bee, does not surprise me at all: I know how
indifferent my bold visitor is to the nature of the victuals
destined for her family. I have noticed her presence in the homes
of bees differing greatly in size and habits: Anthophorae, Osmiae,
Chalicodomae, Anthidia. The Stelis exploited on my table is one
victim more; and that is all. The interest does not lie there.
The interest lies in the maneuvers of the insect, which I am able
to follow under the most favorable conditions.
Bent sharply at right angles, like a couple of broken matches, the
antennae feel the cocoon with their tips alone. The terminal joint
is the home of this strange sense which discerns from afar what no
eye sees, no scent distinguishes and no ear hears. If the point
explored be found suitable, the insect hoists itself on tiptoe so
as to give full scope to the play of its mechanism; it brings the
tip of the belly a little forward; and the entire ovipositor--
inoculating-needle and scabbard--stands perpendicular to the
cocoon, in the center of the quadrilateral described by the four
hind legs, an eminently favorable position for obtaining the
maximum effect. For some time, the whole of the awl bears on the
cocoon, feeling all round with its point, groping about; then,
suddenly, the boring needle is released from its sheath, which
falls back along the body, while the needle strives to make its
entrance. The operation is a difficult one. I see the insect make
a score of attempts, one after the other, without succeeding in
piercing the tough wrapper of the Stelis. Should the instrument
not penetrate, it retreats into its sheath and the insect resumes
its scrutiny of the cocoon, sounding it point by point with the
tips of its antennae. Then further thrusts are tried until one
succeeds.
The eggs are little spindles, white and gleaming like ivory, about
two-thirds of a millimeter in length. They have not the long,
curved peduncle of the Leucospis' eggs; they are not suspended from
the ceiling of the cocoon like these, but are laid without order
around the fostering larva. Lastly, in a single cell and with a
single mother, there is always more than one laying; and the number
of eggs varies considerably in each. The Leucospis, because of her
great size, which rivals that of her victim, the Bee, finds in each
cell provisions enough for one and one alone. When, therefore,
there is more than one set of eggs in any one cell, this is due to
a mistake on her part and not a premeditated result. Where the
whole ration is required for the meals of a single grub, she would
take good care not to install several if she could help it. Her
competitor is not called upon to observe the same discretion. A
Chalicodoma grub gives the dwarf the wherewithal to portion a score
of her little ones, who will live in common and in all comfort on
what a single son of the giantess would eat up by himself. The
tiny boring engineer, therefore, always settles a numerous family
at the same banquet. The bowl, ample for a dozen or two, is
emptied in perfect harmony.
Curiosity made me count the brood, to see if the mother was able to
estimate the victuals and to proportion the number of guests to the
sumptuousness of the fare provided. My notes mention fifty-four
larvae in the cell of a masked Anthophora (Anthophora personata).
No other census attained this figure. Possibly, two different
mothers had laid their eggs in this crowded habitation. With the
Mason bee of the Walls, I see the number of larvae vary, in
different cells, between four and twenty-six; with the mason bee of
the Sheds, between five and thirty-six; with the three-horned
Osmia, who supplied me with the largest number of records, between
seven and twenty-five; with the blue Osmia (Osmia cyanea, KIRB.),
between five and six; with the Stelis (Stelis nasuta), between four
and twelve.
The first return and the last two seem to point to some relation
between the abundance of provisions and the number of consumers.
When the mother comes upon the bountiful larva of the masked
Anthophora, she gives it half-a-hundred to feed; with the Stelis
and the blue Osmia, niggardly rations both, she contents herself
with half-a-dozen. To introduce into the dining room only the
number of boarders that the bill of fare will allow would certainly
be a most deserving performance, especially as the insect is placed
under very difficult conditions to judge the contents of the cell.
These contents, which lie hidden under the ceiling, are invisible;
and the insect can derive its information only from the outside of
the nest, which varies in the different species. We should
therefore have to admit the existence of a particular power of
discrimination, a sort of discernment of the
species, which is recognized as large or small from the outward
aspect of its house. I refuse to go to this length in my
conjectures, not that instinct seems to me incapable of such feats,
but because of the particulars obtained from the three-horned Osmia
and the two mason bees.
In the cells of these three species, I see the number of larvae put
out to nurse vary in so elastic a fashion that I must abandon all
idea of proportionate adjustment. The mother, without troubling
unduly whether there be an excess or a dearth of provisions for her
family, has filled the cells as her fancy prompted, or rather
according to the number of ripe ovules contained in her ovaries at
the time of the laying. If food be over-plentiful, the brood will
be all the better for it and will grow bigger and stronger; if food
be scarce, the famished youngsters will not die, but will remain
smaller. Indeed, with both the larva and the full grown insect, I
have often observed a difference in size which varies according to
the density of the population, the members of a small colony being
double the size of their overcrowded neighbors.
The grubs are white, tapering at both ends, sharply segmented and
covered all over their bodies with a coat of fine, soft hairs which
is invisible except under the lens. The head consists of a little
knob much smaller in diameter than the body. In this head, the
microscope reveals mandibles consisting of fine spikes of a tawny
red, which spread into a wide, colorless base. Deprived of any
indentation, incapable of chewing anything between their awl-shaped
ends, these two tools serve at best to fix the grub slightly at
some point of the fostering larva. Useless for carving, therefore,
the mouth is a pure osculatory sucker, which drains the provisions
by a process of exudation through the skin. We see here repeated
what the Anthrax and the Leucospis have already shown us: the
gradual exhaustion of a victim which the parasite consumes without
killing it.
It is a curious spectacle even after that of the Anthrax. We have
here twenty or thirty starvelings, all with their mouths pressed,
as for a kiss, to the body of the plump larva, which, from day to
day, fades and shrinks without the least appreciable wound, thus
keeping fresh until reduced to a shriveled slough. If I disturb
the gluttonous swarm, all, with a sudden recoil, let go, drop off
and flounder around the foster mother. They are no less prompt in
resuming their savage kisses. I need not add that neither at the
point where they leave off nor at the point where they recommence
is there the faintest trace of liquid. The oily exudation occurs
only when the pump is at work. To linger over this strange method
of feeding is superfluous after what I have said about the Anthrax.
The appearance of the full grown insect takes place at the
beginning of summer, after nearly a whole year's stay in the
invaded dwelling. The large number of inhabitants of one and the
same cell led me to think that the work of deliverance ought to
present a certain interest. They are all equally anxious to clear
the walls of the prison at the earliest possible moment and to come
forth into the great festival of the sun: do they all at the same
time, in a confused horde, attack the ceiling which has to be
pierced? Is the work of deliverance arranged in the general
interest? Or is individual selfishness the only rule? These are
the questions which observation will answer.
A little in advance of the proper season, I transfer each family
into a short glass tube, which will represent the natal cell. A
good, thick cork, quite a centimeter deep, is the obstacle to be
pierced for an outlet. Well, instead of the mad haste and the
ruinous lack of organization which I expected to find, my broods
show me in their glass prison an exceedingly well regulated
workshop. One insect, one only, works at perforating the cork.
Patiently, with its mandibles, grain by grain, it digs a tunnel the
width of its body. The gallery is so narrow that, in order to
return to the tube, the worker has to move backwards. It is a slow
process; and it takes hours and hours to dig the hole, a hard job
for the frail miner.
Should her fatigue become too great, the excavator leaves the
forefront and mingles with the crowd, to polish and dust herself.
Another, the first neighbor at hand, at once takes her place and is
herself relieved by a third when her task is done. Others again
take their turn, always one at a time, so much so that the works
are never at a standstill and never overcrowded. Meanwhile, the
multitude keeps out of the way, quietly and patiently. There is no
anxiety as to the deliverance. Success will come: of that they are
all convinced. While waiting, one washes her antennae by passing
them through her mouth, another polishes her wings with her hind
legs, another frisks about to while away the period of inaction.
Some are making love, a sovran means of killing time, whether one
be born that day or twenty years ago.
Some, I said, make love. These favored ones are rare; they hardly
count. Is it through indifference? No, but the gallants are
lacking. The sexes are very unequally represented in the
population of a cell: the males are in a wretched minority and
sometimes even completely absent. This poverty did not escape the
older observers. Brulle [Gaspard August Bru11e (1809-1873)], the
author of many works on natural history and one of the founders of
the Societe entomologique de France), the only author whom I am
able to consult in my hermitage, says, literally: 'The males do not
appear to be known.'
I, for my part, know them; but, considering their feeble number, I
keep asking myself what part they play in a harem so
disproportionate to their forces. A few figures will show us what
my hesitations are based upon.
In twenty-two Osmia cocoons (Osmia tricornis), the total census of
the inmates yields three hundred and fifty-four, of whom forty-
seven are males and three hundred and seven females. The average
number of inmates, therefore, is sixteen individuals; and there are
six females at least to one male. This disparity is maintained, in
more or less marked proportions, whatever the species of the bee
invaded. In the cocoons of the Mason bee of the Sheds, I discover
the average proportion to be six females to one male; in those of
the Mason bee of the Walls, I find one male to fifteen females.
These facts, which I am unable to state with any greater precision,
are enough to give rise to the suspicion that the males, who are
even tinier dwarfs than the females and who, moreover, like all
insects, are injured by a single act of pairing, must, in most
cases, remain strangers to the females. Can the mothers, in fact,
dispense with their assistance, without being deprived of offspring
on that account? I do not say yes, but I do not say no. The
duality of the sexes is a hard problem. Why two sexes? Why not
just one? It would have been much simpler and saved a great deal
of foolery. Why such a thing as sex, when the tuber of the
Jerusalem artichoke can do without it? These are the pregnant
questions suggested to me, in the end, by Monodontomerus cupreus,
the insect so infinitesimal in body and so overpowering in name
that I had really vowed never to speak of it again by its official
designation.
CHAPTER IV LARVAL DIMORPHISM
If the reader has paid any attention to the story of the Anthrax,
he must have perceived that my narrative is incomplete. The fox in
the fable saw how the lion's visitors entered his den, but did not
see how they went out. With us, it is the converse: we know the
way out of the mason bee's fortress, but we do not know the way in.
To leave the cell of which he has eaten the owner, the Anthrax
becomes a perforating machine, a living tool from which our own
industry might take a hint if it required new drills for boring
rocks. When the exit tunnel is opened, this tool splits like a pod
bursting in the sun; and from the stout framework there escapes a
dainty fly, a velvety flake, a soft fluff that astounds us by its
contrast with the roughness of the depths whence it ascends. On
this point, we know pretty well what there is to know. There
remains the entrance into the cell, a puzzle that has kept me on
the alert for a quarter of a century.
To begin with, it is evident that the mother cannot lodge her egg
in the cell of the mason bee, which has been long closed and
barricaded with a cement wall by the time that the Anthrax makes
her appearance. To penetrate it, she would have to become an
excavating tool once more and resume the cast-off rags which she
left behind in the exit window; she would have to retrace her
steps, to be reborn a pupa; and life knows none of these
retrogressions. The full grown insect, if endowed with claws,
mandibles and plenty of perseverance, might at a pinch force the
mortar casket; but the fly is not so endowed. Her slender legs
would be strained and deformed by merely sweeping away a little
dust; her mouth is a sucker for gathering the sugary exudations of
the flowers and not the solid pincers needed for the crumbling of
cement. There is no auger either, no bore copied from that of the
Leucospis, no implement of any kind that can work its way into the
thickness of the wall and dispatch the egg to its destination. In
short, the mother is absolutely incapable of settling her eggs in
the chamber of the Mason bee.
Can it be the grub that makes its own way into the storeroom, that
same grub which we have seen draining the Chalicodoma with its
leech-like kisses? Let us call the creature to mind: a little oily
sausage, which stretches and curls up just where it lies, without
being able to shift its position. Its body is a smooth cylinder;
its mouth simply a circular lip. Not one ambulatory organ does it
possess; not even hairs, protuberances or wrinkles to enable it to
crawl. The animal is made for digestion and immobility. Its
organization is incompatible with movement; everything tells us so
in the clearest fashion. No, this grub is even less able than the
mother to make its way unaided into the mason's dwelling. And yet
the provisions are there; those provisions must be reached: it is a
matter of life or death; to be or not to be. Then how does the fly
set about it? It would be vain for me to question probabilities,
too often illusory; to obtain a reply of any value, I have but one
resource; I must attempt the nearly impossible and watch the
Anthrax from the egg onwards.
Although Anthrax flies are fairly common, in the sense of there
being several different species, they are not plentiful when it is
a case of wanting a colony populous enough to admit of continuous
observation. I see them, now here, now there, in the fiercely sun-
scorched places, flitting hither and thither on the old walls, the
slopes and the sand, sometimes in small platoons, most often
singly. I can expect nothing of those vagabonds, who are here
today and gone tomorrow, for I know nothing of their settlements.
To keep a watch on them, one by one, in the blazing heat, is very
painful and very unfruitful, as the swift-winged insect has a habit
of disappearing one knows not whither just when a prospect of
capturing its secret begins to offer. I have wasted many a patient
hour at this pursuit, without the least result.
There might be some chance of success with Anthrax flies whose home
was known to us beforehand, especially if insects of the same
species formed a pretty numerous colony. The inquiries begun with
one would be continued with a second and with more, until a
complete verdict was forthcoming. Now, in the course of my long
entomological career, I have met with but two species of Anthrax
that fulfilled this condition and were to be found regularly: one
at Carpentras; the other at Serignan. The first, Anthrax sinuata,
FALLEN, lives in the cocoons of Osmia tricornis, who herself builds
her nest in the old galleries of the hairy-footed Anthophora; the
second, Anthrax trifasciata, MEIGEN, exploits the Chalicodoma of
the Sheds. I will consult both.
Once more, here am I, somewhat late in life, at Carpentras, whose
rude Gallic name sets the fool smiling and the scholar thinking.
Dear little town where I spent my twentieth year and left the first
bits of my fleece upon life's bushes, my visit of today is a
pilgrimage; I have come to lay my eyes once more upon the place
which saw the birth of the liveliest impressions of my early days.
I bow, in passing, to the old college where I tried my prentice
hand as a teacher. Its appearance is unchanged; it still looks
like a penitentiary. Those were the views of our mediaeval
educational system. To the gaiety and activity of boyhood, which
were considered unwholesome, it applied the remedy of narrowness,
melancholy and gloom. Its houses of instruction were, above all,
houses of correction. The freshness of Virgil was interpreted in
the stifling atmosphere of a prison. I catch a glimpse of a yard
between four high walls, a sort of bear pit, where the scholars
fought for room for their games under the spreading branches of a
plane tree. All around were cells that looked like horse boxes,
without light or air; those were the classrooms. I speak in the
past tense, for doubtless the present day has seen the last of this
academic destitution.
Here is the tobacco shop where, on Wednesday evening, coming out of
the college, I would buy on credit the wherewithal to fill my pipe
and thus to celebrate on the eve the joys of the morrow, that
blessed Thursday [the weekly half-holiday in French schools] which
I considered so well employed in solving hard equations,
experimenting with new chemical reagents, collecting and
identifying my plants. I would make my timid request, pretending
to have come out without my money, for it is hard for a self-
respecting man to admit that he is penniless. My candor appears to
have inspired some little confidence; and I obtained credit, an
unprecedented thing, with the representative of the revenue. [The
government in France has the sole control of the tobacco trade,
which forms an important branch of the inland revenue.] Ah, why did
not I open a shop and expose for sale some packets of candles, a
dozen dried cod, a barrel of sardines and a few cakes of soap! I am
no more of a fool nor any less industrious than another; and I
should have made my way. But, as it was, what could I expect? As
an accoucheur of brains, a molder of intellects, I had no claim
even to bread and cheese.
Here is my former habitation, occupied since by droning monks. In
the embrasure of that window, sheltered from profane hands, between
the closed outer shutters and the panes, I used to keep my
chemicals, bought for a few sous cheated out of the weekly budget
in the early days of our housekeeping. The bowl of a pipe was my
crucible, a sweet jar my retort, mustard pots my receptacles for
oxides and sulfides. My experiments, harmless or dangerous, were
made on a corner of the fire beside the simmering broth.
How I should love to see that room again where I pored over
differentials and integrals, where I calmed my poor burning head by
gazing at Mont Ventoux, whose summit held in store for my coming
expedition' those denizens of arctic climes, the saxifrage and the
poppy! And to see my familiar friend, the blackboard which I hired
at five francs a year from a crusty joiner, that board whose value
I paid many times over, though I. could never buy it outright, for
want of the necessary cash! The conic sections which I described on
that blackboard, the learned hieroglyphics!
Though all my efforts, which were the more deserving because I had
to work alone, led to almost nothing in that congenial calling, I
would begin it all over again if I could. I should love to be
conversing for the first time with Leibnitz and Newton, with
Laplace and Lagrange, with Cuvier and Jussieu, even if I had
afterwards to solve that other arduous problem: how to procure
one's daily bread. Ah, young men, my successors, what an easy time
you have of it today! If you don't know it, then let me tell you so
by means of these few pages from the life of one of your elders.
But let us not forget our insects, while listening to the echoes of
illusions and difficulties roused in my memories by the cupboard
window and the hired blackboard. Let us go back to the sunken
roads of the Legue, which have become classic, so they say, since
the appearance of my notes on the Oil beetles. Ye illustrious
ravines, with your sun-baked slopes, if I have contributed a little
to your fame, you, in your turn, have given me many fair hours of
forgetfulness in the happiness of learning. You, at least, did not
lure me with vain hopes; all that you promised you gave me and
often a hundredfold. You are my promised land, where I would have
sought at the last to pitch my observer's tent. My wish was not to
be realized. Let me, at least, in passing, greet my beloved
animals of the old days.
I raise my hat to Cerceris tuberculata, whom I see engaged on that
slant, storing her Cleonus [a large species of weevil]. As I saw
her then, so I see her now: the same staggering attempts to hoist
the prey to the mouth of the burrow; the same brawls between males
watching in the brushwood of the kermes oak. The sight of them
sends a younger blood coursing through my veins; I receive as it
were the breath of a new springtime of life. Time presses; let us
pass on.
Another bow on this side. I hear buzzing up above, on that ledge,
a colony of Sphex wasps, stabbing their crickets. We will give
them a friendly glance, but no more. My acquaintances here are too
numerous; I have not the leisure to renew my former relations with
all of them. Without stopping, a wave of the hat to the Philanthi
[bee-hunting wasps] who send the long avalanches of rubbish
streaming down from their nests; and to Stizus ruficornis, [a
hunting wasp] who stacks her praying mantises between two flakes of
sandstone; and to the silky Ammophila [a digger wasp] with the red
legs, who collects an underground store of loopers [also known as
measuring worms, the larvae or caterpillars of the geometrid moth]
and to the Tachtyti [hunting wasps], devourers of locusts; and to
the Eumenes, builders of clay cupolas on a bough.
Here we are at last. This high, perpendicular rock, facing the
south to a length of some hundreds of yards and riddled with holes
like a monstrous sponge, is the time-honored dwelling place of the
hairy-footed Anthophora and of her rent free tenant, the three-
horned Osmia. Here also swarm their exterminators: the Sitaris
beetle, the parasite of the Anthophora; the Anthrax fly, the
murderer of the Osmia. Ill informed as to the proper period, I
have come rather late, on the 10th of September. I should have
been here a month ago, or even by the end of July, to watch the
fly's operations. My journey threatens to be fruitless: I see but
a few rare Anthrax flies, hovering round the face of the cliff. We
will not despair, however, and we will begin by consulting the
locality.
The Anthophora's cells contain this bee in the larval stage. Some
of them provide me with the oil beetle and the Sitaris, rare finds
at one time, today of no use to me. Others contain the Melecta [a
parasitic bee] in the form of a highly colored pupa, or even in
that of the full grown insect. The Osmia, still more precocious,
though dating from the same period, shows herself exclusively in
the adult form, a bad omen for my investigations, for what the
Anthrax demands is the larva and not the perfect insect. The fly's
grub doubles my apprehensions. Its development is complete, the
larva on which it feeds is consumed, perhaps several weeks ago. I
no longer doubt but that I have come too late to see what happens
in the Osmia's cocoons.
Is the game lost? Not yet. My notes contain evidence of Anthrax
flies hatching in the latter half of September. Besides, those
whom I now see exploring the rock are not there to take exercise:
their preoccupation is the settling of the family. These belated
ones cannot tackle the Osmia, who, with her firm, adult flesh,
would not suit the nursling's delicate needs and who, moreover,
powerful as she is, would offer resistance. But in autumn a less
numerous colony of honey gatherers takes the place, upon the
slope, of the spring colony, from which it differs in species. In
particular, I see the Diadem Anthidium [a clothier bee who lines
her nest with wool and cotton] at work, entering her galleries at
one time with her harvest of pollen dust and at another with her
little bale of cotton. Might not these autumnal Bees be
themselves exploited by the Anthrax, the same that selected the
Osmia as her victim a couple of months earlier? This would
explain the presence of the Anthrax flies whom I now see fussing
about.
A little reassured by this conjecture, I take my stand at the foot
of the rock, under a broiling sun; and, for half a day, I follow
the evolutions of my flies. They flit quietly in front of the
slope, at a few inches from the earthy covering. They go from one
orifice to the next, but without even penetrating. For that
matter, their big wings, extended crosswise even when at rest,
would resist their entrance into a gallery, which is too narrow to
admit those spreading sails. And so they explore the cliff, going
to and fro and up and down, with a flight that is now sudden, now
smooth and slow. From time to time, I see the Anthrax quickly
approach the wall and lower her abdomen as though to touch the
earth with the end of her ovipositor. This proceeding takes no
longer than the twinkling of an eye. When it is done, the insect
alights elsewhere and rests. Then it resumes its sober
flight, its long investigations and its sudden blows with the tip
of its belly against the layer of earth. The Bombylii [bee flies]
observe similar tactics when soaring at a short height above the
ground.
I at once rushed to the spot touched, lens in hand, in the hope of
finding the egg which everything told me was laid during that tap
of the abdomen. I could distinguish nothing, in spite of the
closest attention. It is true that my exhaustion, together with
the blinding light and scorching heat, made examination very
difficult. Afterwards, when I made the acquaintance of the tiny
thing that issues from that egg, my failure no longer surprised me.
In the leisure of my study, with my eyes rested and with my most
powerful glasses held in a hand no longer shaking with excitement
and fatigue, I have the very greatest difficulty in finding the
infinitesimal creature, though I know exactly where it lies. Then
how could I see the egg, worn out as I was under the sun-baked
cliff, how discover the precise spot of a laying performed in a
moment by an insect seen only at a distance? In the painful
conditions wherein I found myself, failure was inevitable.
Despite my negative attempts, therefore, I remain convinced that
the Anthrax flies strew their eggs one by one, on the spots
frequented by those bees who suit their grubs. Each of their
sudden strokes with the tip of the abdomen represents a laying.
They take no precaution to place the germ under cover; for that
matter, any such precaution would be rendered impossible by the
mother's structure. The egg, that delicate object, is laid roughly
in the blazing sun, between grains of sand, in some wrinkle of the
calcined chalk. That summary installation is sufficient, provided
the coveted larva be near at hand. It is for the young grub now to
manage as best it can at its own risk and peril.
Though the sunken roads of the Legue did not tell me all that I
wished to know, they at least made it very probable that the coming
grub must reach the victualled cell by its own efforts. But the
grub which we know, the one that drains the bag of fat which may be
a Chalicodoma larva or an Osmia larva, cannot move from its place,
still less indulge in journeys of discovery through the thickness
of a wall and the web of a cocoon. So an imperative necessity
presents itself: there must perforce be an initial larva form,
capable of moving and organized for searching, a form under which
the grub would attain its end. The Anthrax would thus possess two
larval states: one to penetrate to the provisions; the other to
consume them. I allow myself to be convinced by the logic of it
all; I already see in my mind's eye the wee animal coming out of
the egg, endowed with sufficient power of motion not to dread a
walk and with sufficient slenderness to glide into the smallest
crevices. Once in the presence of the larva on which it is to
feed, it doffs its travelling dress and becomes the obese animal
whose one duty it is to grow big and fat in immobility. This is
all very coherent; it is all deduced like a geometrical
proposition. But to the wings of imagination, however smooth their
flight, we must prefer the sandals of observed facts, the slow
sandals with the leaden soles. Thus shod, I proceed.
Next year, I resume my investigations, this time on the Anthrax of
the Chalicodoma, who is my neighbor in the surrounding wastelands
and will allow me to repeat my visits daily, morning and evening if
need be. Taught by my earlier studies, I now know the exact period
of the Bee's hatching and therefore of the Anthrax' laying, which
must take place soon after. Anthrax trifasciata settles her family
in July, or in August at latest. Every morning, at nine o'clock,
when the heat begins to be unendurable and when, to use [the
author's gardener and factotum] Favier's expression, an extra log
is flung on the bonfire of the sun, I take the field, prepared to
come back with my head aching from the glare, provided that I bring
home the solution of my puzzle. A man must have the devil in him
to leave the shade at this time of the year. And what for, pray?
To write the story of a fly! The greater the heat, the better my
chance of success. What causes me to suffer torture fills the
insect with delight; what prostrates me braces the fly. Come
along!
The road shimmers like a sheet of molten steel. From the dusty and
melancholy olive trees rises a mighty, throbbing hum, a great
andante whose executants have the whole sweep of woods for their
orchestra. 'Tis the concert of the Cicada, whose bellies sway and
rustle with increasing frenzy as the temperature rises. The
strident scrapings of the Cicada of the Ash, the Carcan of the
district, lend their rhythm to the one note symphony of the common
cicada. This is the moment: come along! And, for five or six
weeks, oftenest in the morning, sometimes in the afternoon, I set
myself to explore the flinty plateau.
The Chalicodoma's nests abound, but I cannot see a single Anthrax
make a black speck upon their surface. Not one, busy with her
laying, settles in front of me. At most, from time to time, I can
just see one passing far away, with an impetuous rush. I lose her
in the distance; and that is all. It is impossible to be present
at the laying of the egg. I know the little that I learnt from the
cliffs in the Legue and nothing more.
As soon as I recognize the difficulty, I hasten to enlist
assistants. Shepherds--mere small boys--keep the sheep in these
stony meadows, where the flocks graze, to the greater glory of our
local mutton, on the camphor saturated badafo, that is to say,
spike lavender. I explain as well as I can the object of my
search; I talk to them of a big black Fly and the nests on which
she ought to settle, the clay nests so well known to those who have
learnt how to extract the honey with a straw in springtime and
spread it on a crust of bread. They are to watch that fly and take
good note of the nests on which they may see her alight; and, on
the same evening, when they bring their flocks back to the village,
they are to tell me the result of their day's work. On receiving
their favorable report, I will go with them, next day, to continue
the observations. They shall be paid for their trouble, of course.
These latter day Corydons have not the manners of antiquity: they
reck little of the seven holed flute cemented with wax, or of the
beechen bowl, preferring the coppers that will take them to the
village inn on Sunday. A reward in ready money is promised for
each nest that fulfils the desired conditions; and the bargain is
enthusiastically accepted.
There are three of them; and I make a fourth. Shall we manage it,
among us all? I thought so. By the end of August, however, my
last illusions were dispelled. Not one of us had succeeded in
seeing the big black Fly perching on the dome of the mason bee.
Our failure, it seems to me, can be explained thus: outside the
spacious front of the Anthophora's settlement, the Anthrax is in
permanent residence. She visits, on the wing, every nook and
corner, without moving away from the native cliff, because it would
be useless to go farther. There is board and lodging here,
indefinitely, for all her family. When some spot is deemed
favorable, she hovers round inspecting it, then comes up suddenly
and strikes it with the tip of her abdomen. The thing is done, the
egg is laid. So I picture it, at least. Within a radius of a few
yards and in a flight broken by short intervals of rest in the sun,
she carries on her search of likely places for the laying and
dissemination of her eggs. The insect's assiduous attendance upon
the same slope is caused by the inexhaustible wealth of the
locality exploited.
The Anthrax of the Chalicodoma labors under very different
conditions. Stay-at-home habits would be detrimental to her. With
her rushing flight, made easy by the long and powerful spread of
her wings, she must travel far and wide if she would found a
colony. The bee's nests are not discovered in groups, but occur
singly on their pebbles, scattered more or less everywhere over
acres of ground. To find a single one is not enough for the fly:
on account of the many parasites, not all the cells, by a long way,
contain the desired larva; others, too well protected, would not
allow of access to the provisions. Very many nests are necessary,
perhaps, for the eggs of one alone; and the finding of them calls
for long journeys.
I therefore picture the Anthrax coming and going in every direction
across the stony plain. Her practiced eye requires no slackened
flight to distinguish the earthen dome which she is seeking.
Having found it, she inspects it from above, still on the wing; she
taps it once and yet once again with the tip of her ovipositor and
forthwith makes off, without having set foot on the ground. Should
she take a rest, it will be elsewhere, no matter where, on the
soil, on a stone, on a tuft of lavender or thyme. Given these
habits--and my observations in the Carpentras roads make them seem
exceedingly probable--it is small wonder that the perspicacity of
my young shepherds and myself should have come to naught. I was
expecting the impossible: the Anthrax does not halt on the mason
bee's nest to proceed with her laying in a methodical fashion; she
merely pays a flying visit.
And so I develop my theory of a primary larval form, differing in
every way from the one which I know. The organization of the
Anthrax must be such, at the beginning, as to permit of its moving
on the surface of the dome where the egg has been dropped so
carelessly; the nascent grub must be supplied with tools to pierce
the concrete wall and enter the Bee's cell through some cranny.
The fly grub, perhaps dragging the remnants of the egg behind it,
must set out in quest of board and lodging almost as soon as it is
born. It will succeed under the guidance of instinct, that faculty
which waits not to number the days and which is as far seeing at
the moment of hatching as after the trials of a busy life. This
primary grub does not seem to me outside the limits of possibility;
I see it, if not in the body, at least in its actions, as plainly
as though it were really under the lens. It exists, if reason be
not a vain and empty guide; I must find it; I shall find it. Never
in the history of my investigations has the logic of things been
more insistent; never has it directed me with greater certainty
towards a magnificent biological theory.
While vainly trying to witness the laying of the eggs, I inquire,
at the same time, into the contents of the Mason bee's nests, in
quest of the grub just issued from the egg. My own harvest and
that of my young shepherds, whose zeal I employ in a task less
difficult than the first, procure me heaps of nests, enough to fill
baskets and baskets. These are all inspected at leisure, on my
work table, with the excitement which the certainty of an
approaching fine discovery never fails to give. The Mason's
cocoons are taken from the cells, inspected without, opened and
inspected within. My lens explores their innermost recesses; speck
by speck, it explores the Chalicodoma's slumbering larva; it
explores the inner walls of the cells. Nothing, nothing, nothing!
For a fortnight and more, nests were rejected and heaped up in a
corner; my study was crammed with them. What hecatombs of
unfortunate sleepers removed from their silken bags and doomed, for
the most part, to a wretched end, despite the care which I took to
put them in a place of safety, where the work of the transformation
might be pursued! Curiosity makes us cruel. I continue to rip up
cocoons. And nothing, nothing! It needed the sturdiest faith to
make me persevere. That faith I possessed; and well for me that I
did.
On the 25th of July--the date deserves to be recorded--I saw, or
rather seemed to see, something move on the Chalicodoma's larva.
Was it an illusion born of my hopes? Was it a bit of diaphanous
down stirred by my breath? It was not an illusion, it was not a
bit of down, it was really and truly a grub. What a moment,
followed by what perplexities! The thing has nothing in common with
the larva of the Anthrax, it suggests rather some microscopic
Thread worm that, by accident, has made its way through the skin of
its host and come to enjoy itself outside. I do not reckon my
discovery as of much value, because I am so greatly puzzled by the
creature's appearance. No matter: we will take a small glass tube
and place inside it the Chalicodoma grub and the mysterious thing
wriggling on the surface. Suppose it should be what I am looking
for? Who knows?
Once warned of the probable difficulty of seeing the animalcule for
which I am hunting, I redouble my attention, so much so that, in a
couple of days, I am the owner of half a score of tiny worms
similar to the one which caused me such excitement. Each of them
is lodged in a glass tube with its Chalicodoma grub. The
infinitesimal thing is so small, so diaphanous, blends to such good
purpose with its host that the least fold of skin conceals it from
my view. After watching it one day through the lens, I sometimes
fail to find it again on the morrow. I think that I have lost it,
that it has perished under the weight of the overturned larva and
returned to that nothing to which it was so closely akin. Then it
moves and I see it again. For a whole fortnight, there was no
limit to my perplexity. Was it really the original larva of the
Anthrax? Yes, for I at last saw my bantlings transform themselves
into the larva previously described and make their first start at
draining their victims with kisses. A few moments of satisfaction
like those which I then enjoyed make up for many a weary hour.
Let us resume the story of the wee animal, now recognized as the
genuine origin of the Anthrax. It is a tiny worm about a
millimeter long and almost as slender as a hair. It is very
difficult to see because of its transparency. When tucked away in
a fold of the skin of its fostering larva, an excessively fine
skin, it remains undiscoverable to the lens. But the feeble
creature is very active: it tramps over the sides of the rich
morsel, walks all round it. It covers the ground pretty quickly,
buckling and unbuckling by turns, very much after the manner of the
looper caterpillar. Its two extremities are its chief points of
support. When at a standstill, it moves its front half in every
direction, as though to explore the space around it; when walking,
it swells out, magnifies its segments and then looks like a bit of
knotted string.
The microscope shows us thirteen rings, including the head. This
head is small, slightly horny, as is proved by its amber color, and
bristles in front with a small number of short, stiff hairs. On
each of the three segments of the thorax there are two long hairs,
fixed to the lower surface; and there are two similar and still
longer hairs at the end of the terminal ring. These four pairs of
bristles, three in front and one behind, are the locomotory organs,
to which we must add the hairy edge of the head and also the anal
button, a sustaining base which might very well work with the aid
of a certain stickiness, as happens with the primary larva of the
Sitaris [a Parasitic Beetle noted for the multiplicity of
transformations undergone by the grub]. We see, through the
transparent skin, two long air tubes running parallel to each other
from the first thoracic segment to the last abdominal segment but
one. They ought to end in two pairs of breathing holes which I
have not succeeded in distinguishing quite plainly. Those two big
respiratory vessels are characteristic of the grubs of flies.
Their mouths correspond exactly with the points at which the two
sets of stigmata open in the Anthrax larva in its second form.
For a fortnight, the feeble grub remains in the condition which I
have described, without growing and very probably also without
nourishment. Assiduous though my visits be, I never perceive it
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