MORE BEETLES
BY
J. HENRI FABRE
TRANSLATED BY
Alexander Teixeira de Mattos
FELLOW OF THE ZOOLOGICAL SOCIETY OF LONDON
NEW YORK
DODD, MEAD AND COMPANY
1922
TRANSLATOR’S NOTE
This, if we count The Life of the Weevil as the third, is the fourth
and last volume on Beetles in the Collected English Edition of Fabre’s
entomological works. The first was entitled The Sacred Beetle and
Others; the second The Glow-worm and Other Beetles.
Of the fourteen chapters, part of the four devoted to the Minotaur
appeared, in an abbreviated form, in The Life and Love of the Insect,
prepared by myself for Messrs. Adam and Charles Black and published in
America by the Macmillan Co. Similarly, The Pine Cockchafer and the two
chapters on the Gold Beetles occur in Mr. Fisher Unwin’s Social Life in
the Insect World (published in America by the Century Co.), translated
by Mr. Bernard Miall, whom I take this opportunity of thanking for his
assistance in the translation of the present volume. These seven
chapters are included in the Collected Edition by arrangement with the
publishers named.
Alexander Teixeira de Mattos.
Chelsea, 29 September, 1921.
CONTENTS
PAGE
TRANSLATOR’S NOTE v
CHAPTER
I THE CETONIÆ 1
II SAPRINI, DERMESTES AND OTHERS 34
III THE BEADED TROX 55
IV MINOTAURUS TYPHŒUS: THE BURROW 72
V MINOTAURUS TYPHŒUS: FIRST ATTEMPTS AT OBSERVATION 98
VI MINOTAURUS TYPHŒUS: FURTHER OBSERVATIONS 125
VII MINOTAURUS TYPHŒUS: MORALITY 152
VIII THE ERGATES; THE COSSUS 172
IX THE PINE COCKCHAFER 194
X THE VEGETARIAN INSECTS 215
XI THE DWARFS 238
XII SOME ANOMALIES 255
XIII THE GOLD BEETLES: THEIR FOOD 278
XIV THE GOLD BEETLES: THEIR NUPTIAL HABITS 299
MORE BEETLES
CHAPTER I
THE CETONIÆ
My hermitage boasts a long, wide lilac-walk. When May is here and the
two rows of bushes, bending beneath their load of clustering blooms,
form pointed arches overhead, this walk becomes a chapel, in which the
loveliest festival of the year is celebrated beneath the kisses of the
morning sun: a peaceful festival, with no flags flapping at the
windows, no expenditure of gun-powder, no drunken squabbles; a festival
of simple creatures disturbed neither by the harsh brass band of the
dance nor by the shouts of the crowd acclaiming the amateur who has
just won a silk handkerchief at the hop, skip and jump. Vulgar delights
of drinks and crackers, how far removed are you from this solemn
celebration!
I am one of the worshippers in the chapel of the lilacs. My orison,
which cannot be translated into words, is a tender and intimate
emotion. Devoutly I make my stations from one column of verdure to
another, telling step by step my observer’s rosary. My prayer is an
“Oh!” of admiration.
To this delicious festival pilgrims have hastened, to gain the Lenten
indulgences and to slake their thirst. Here, dipping their tongues by
turns into the holy-water stoup of the same flower, are the Anthophora
[1] and her tyrant the Melecta. [2] Robber and victim sip their nectar
like good neighbours. There is no ill-feeling: between them. Both
attend to their own affairs in peace. They seem not to know each other.
The Osmiæ, [3] clad in black-and-red velvet, dust their ventral brushes
with pollen and make hoards of meal in the reeds round about. Here are
the Eristales, [4] noisy, giddy-pated insects, whose wings shimmer in
the sun like scales of mica. Drunk with syrup, they withdraw from the
festival and sleep off their debauch in the shadow of a leaf.
These others are Wasps, Polistes, [5] hot-tempered swashbucklers. When
these intolerant creatures are abroad, peaceful insects withdraw and
establish themselves elsewhere. Even the Hive-Bee, predominating in
numbers and ever ready to unsheathe her sting, makes way for them, busy
as she is gathering in the harvest.
These thick-set, richly variegated Moths are Sesiæ, with wings not
dusted with scales throughout. The bare zones, like so much transparent
gauze, contrast with the covered zones and are an added beauty. The
sober sets off the magnificent.
Here is a crazy swarm, eddying, receding, returning, rising and
falling. It is the ballet of the common Butterfly-folk, the Cabbage
Butterflies, [6] all white, with black, eye-shaped dots. They flirt in
mid-air, pursuing and pressing their attentions on one another, until,
weary of frolic, now one, now another of the dancers alights once more
upon the lilacs, quenching her thirst from the amphoræ of the flowers.
While the proboscis dives down the narrow throat of the blossom,
sucking the nectar at the base, the wings, gently fluttering, are
raised above the back, expanding anew and again standing erect.
Almost as numerous but less sudden in flight, because of his
wide-spreading wings, is the Machaon, the magnificent Swallow-tail
Butterfly, with the orange spots and the blue crescents.
The children have come to join me. They are enraptured by this elegant
creature, which always escapes their pouncing hands and flies a little
farther to taste the nectar of the flowers while moving its wings after
the fashion of the Cabbage Butterfly. If the pump is working quietly in
the sunlight, if the syrup is rising easily, this gentle fanning of the
wings is in all these Butterflies a sign of satisfaction.
A catch! Anna, the youngest of the whole household, gives up all hope
of capturing the Swallow-tails, who never wait for her nimble little
hand to seize them. She has found something more to her liking. It is
the Cetonia. The handsome insect has not yet recovered from the chill
of morning; it lies slumbering all golden on the lilac-blossoms,
unconscious of danger, incapable of flight. It is plentiful. Five or
six are quickly caught. I intervene, so that the rest may be left in
peace. The booty is placed in a box, with a bed of blossoms. Presently,
during the heat of the day, the Cetonia, with a long thread tied to one
leg, will fly in circles round the little girl’s head.
Childhood is pitiless because it does not understand, for nothing is
more cruel than ignorance. None of my madcaps will heed the sufferings
of the insect, a melancholy galley-slave chained to a cannon-ball.
These artless minds find amusement in torture. I dare not always call
them to order, for I admit that I on my side am also guilty, though I
am ripened by experience, to some extent civilized and beginning to
know a thing or two. They inflict suffering for the sake of amusement
and I for the sake of information: is it not really the same thing? Is
there a very definite line of demarcation between the experiments of
knowledge and the puerilities of childhood? I cannot see it.
Human barbarity in the past employed the rack to force a prisoner to
speak. Am I anything but a torturer when I interrogate my insects and
put them to the rack to wrest some secret from them? Let Anna get such
pleasure as she can out of her prisoners, for I am meditating something
worse. The Cetonia has things to reveal to us, things that will
interest us, beyond a doubt. Let us try to obtain these revelations. We
cannot, of course, do so without serious inconvenience to the insect.
So be it; and now let us proceed: we will silence our kindly scruples
for the sake of the story.
Among the guests at the festival of the lilacs the Cetonia deserves to
be most honourably mentioned. He is of a good size, which lends itself
to observation. Though deficient in elegance with his massive,
square-cut build, he has splendour in his favour: the gleam of copper,
the flash of gold, or the austere magnificence of bronze as it leaves
the brass-founder’s burnisher. He is a regular frequenter of my
enclosure, a neighbour, and will therefore spare me the trips which are
beginning to tell upon me. Lastly—and this is an excellent quality when
one wishes to be understood by all one’s readers—he is known to
everybody, if not by his classic name, [7] at least as an object that
often meets the eye.
Who has not seen him, like a great emerald lying at the heart of a
rose, whose tender blush he enhances by the richness of his jewellery?
In this voluptuous bed of stamens and petals he is encrusted,
motionless; he remains there night and day, intoxicated by the heady
fragrance, drunk with nectar. It needs the stimulus of fierce sunlight
to arouse him from his bliss and set him soaring with a buzzing flight.
To watch the idle Beetle in his sybaritic bed, without further
information, one would hardly suspect him of gluttony. What nourishment
can he find on a rose or a cluster of hawthorn-blossom? At most a tiny
drop of sugary exudation, for he does not browse upon the petals, still
less upon the foliage. And can this, a mere nothing, satisfy that big
body? I hesitate to believe it.
In the first week of August I placed in a cage fifteen Cetoniæ that had
just burst their shells in my rearing-jars. Bronze above and violet
underneath, they belong to the species C. metallica, Fab. I provide
them, according to the resources of the day, with pears, plums, melon
or grapes.
It is a joy to see them feast. Once at table they do not budge. Not a
movement, not even a shifting of the feet. With their heads in the
fruit-pulp, often with their bodies completely submerged, they sip and
swallow night and day, in the darkness, in the sunlight, without a
break. Surfeited with sweets, the guzzlers hold on. Collapsing under
the table, that is to say, under the deliquescent fruit, they still
lick their lips, in the blissful drowsiness of a child that drops
asleep with its slice of bread and jam at its lips.
There is no sportiveness in their orgy, even when the sun shines
fiercely into the cage. All activity is suspended; the time is wholly
devoted to the joys of the stomach. In this torrid heat it is so
pleasant to lie under the greengage, oozing with juice! With such good
things at hand, why go flying across the fields where everything is
parched? None dreams of such a thing. There is no scaling of the walls
of the cage, no sudden unfurling of the wings in an attempt to escape.
This life of junketing has already lasted a fortnight without producing
satiety. Such a protracted banquet is not frequent; we do not find it
even in the Dung-beetles, who are zealous eaters. When the Sacred
Beetle, spinning his little unbroken cord of intestinal refuse, has
remained a whole day on a tasty morsel, it is the most that the
gormandizer can allow himself. [8] But my Cetoniæ have been feasting on
the sweets of the plum and pear for a full fortnight; and there is no
sign yet that they have had enough. When will the orgy make way for the
wedding and the cares of the future?
Well, there will be no wedding and no family-cares this year. These are
put off till next year: a singular postponement, quite at variance with
the usual custom, which is to be extremely expeditious in these
important matters. It is the season of fruits; and the Cetonia, a
passionate glutton, means to enjoy these good things without being
diverted from them by the worries of egg-laying. The gardens offer the
luscious pear and the wrinkled fig, its eye moist with syrup. The
greedy creature takes possession of them and becomes oblivious to all
else.
However, the dog-days are becoming more and more pitiless. Day after
day, another load of brushwood, as our peasants say, is added to the
furnace of the sun. Excessive heat, like cold, produces a suspension of
life. To kill the time, creatures that are grilled or frozen go to
sleep. The Cetoniæ in my breeding-cage bury themselves in the sand, a
couple of inches down. The sweetest fruits no longer tempt them: it is
too hot.
It takes the moderate temperature of September to wake them from their
torpor. At this season they reappear on the surface; they settle down
to my bits of melon-rind, or slake their thirst at a small bunch of
grapes, but soberly, taking only short draughts. The hunger-fits of
early days and the interminable filling of the belly have gone for
ever.
Now comes the cold weather. Again my captives disappear underground.
Here they pass the winter, protected only by a layer of sand a few
inches in depth. Under this slight covering, in their wooden shelter,
exposed to all the winds of heaven, they are not endangered by the
severe frosts. I thought them susceptible to cold, but I find that they
bear the hardships of the winter remarkably well. They have retained
the robust constitution of the larvæ, which I used to find, to my
astonishment, lying stiff and stark in a block of frozen snow, yet
returning to life when carefully thawed.
March is not over before signs of life reappear. My buried Beetles
emerge, climb up the wire trellis, wandering about if the sun is kind,
going back into the sand if the air grows colder. What am I to give
them? There is no fruit. I serve them some honey in a paper dish. They
go to it without any marked assiduity. Let us find something more to
their taste. I offer them some dates. The exotic fruit, a delicious
pulp in a thin skin, suits them very well, despite its novelty: they
could set no greater store by pears or figs. The dates bring us to the
end of April, the time of the first cherries.
We have now returned to the regulation diet, the fruits of the country.
A very moderate consumption takes place: the hour is past for feats of
gastric prowess. Very soon my boarders grow indifferent to food. I
surprise them in nuptial embraces, a sign that egg-laying is near at
hand. In anticipation of events, I have placed in the cage, level with
the soil, a pot full of dead, half-rotten leaves. About the summer
solstice I see them enter it, one by one, remaining in it for some
little time. Then, having finished their business, they return to the
surface. For a week or two longer, they wander about, finally hiding
themselves in the sand, at no great depth, and dying.
Their successors are in the pot of rotten leaves. Before the end of
June I find, in the tepid mass, plenty of recent eggs and very young
larvæ. I now have the explanation of a peculiarity which caused me some
confusion at the time of my earlier studies. When rummaging through the
big heap of leaf-mould which, in a shady corner of the garden, provides
me yearly with a rich colony of Cetoniæ, I used to find, under my
trowel, in July and August, intact cocoons which would soon split open
under the thrust of the insect inside; I also found the adult Cetonia,
who had emerged from her strong-box that very day, and quite close to
these I would find very young larvæ, which had only just made their
appearance. I had before my eyes the crazy paradox of children born
before their parents.
The breeding-cage has cleared up these obscure points completely. It
has taught me that the Cetonia, in the adult form, lives through a
whole year and the summer of the following year. The cocoon is broken
during the summer heats of July and August. The regular thing would be,
provided the season were propitious, to think at once of the family,
after indulging in a few nuptial frolics. This is the general rule
among other insects. For them the present form is an efflorescence of
brief duration, which the needs of the future employ as quickly as may.
The Cetonia does not display this haste. She was a gross eater in her
days of pot-bellied grubhood; she remains a gross eater beneath the
splendour of her adult cuirass. She spends her life, so long as the
heat is not too overwhelming, in the jam-factory of the orchard:
apricots, pears, peaches, figs and plums. Lingering over her meal, she
forgets all else and defers her egg-laying to the following year.
After the torpor of hibernation in some place of shelter, she reappears
with the first days of spring. But there is no fruit now; and last
year’s glutton, who, for that matter, has become a frugal eater,
whether by necessity or by temperament, has no other resource than the
niggardly drinking-bar of the flowers. When June has come, she sows her
eggs in a heap of vegetable mould, beside the chrysalids whence the
adult insect will emerge a little later. This being so, unless we are
in the secret, we behold the mad spectacle of the egg preceding the
mother that lays it.
Among the Cetoniæ that make their appearance in the course of the same
year we must therefore distinguish two generations. Those of the
spring, the inhabitants of the roses, have lived through the winter.
They must lay their eggs in June and then die. Those of the autumn,
passionate fruit-lovers, have recently left their nymphal dwellings.
They will hibernate and will lay their eggs about the middle of the
following summer.
We have come to the longest days of the year; this is the moment. In
the shadow of the pines, against the wall of the enclosure, stands a
heap some cubic yards in volume, formed of all the rubbish of the
garden and particularly of dead leaves collected at the time of their
fall. This is the compost-factory which supplies the needs of my potted
plants. Now this bank of corruption, warmed by the slow decomposition
which is working in it, is a paradise for the Cetoniæ in their larval
state. The fat grub swarms there, finding abundant provender in the
shape of fermented vegetable matter and an agreeable warmth, even in
the heart of the winter.
Four species live here, thriving admirably, despite the annoyance which
my curiosity causes them. The most numerous is the Metallic Cetonia (C.
metallica, Fab.). This is the insect that provides me with the greater
part of my data. The others are the common Golden Cetonia, or
Rose-chafer (C. aurata, Linn.), the Dark-brown Cetonia (C. morio, Fab.)
and lastly the small Funeral-pall Cetonia (C. stictica, Linn.). [9]
Let us inspect the heap about nine or ten o’clock in the morning. We
must be diligent and patient, for the advent of the laying mothers is
subject to capricious delays and often makes us wait in vain. Chance
favours us. Here is a Metallic Cetonia dropping in from some
neighbouring spot. In wide circles she flies once or twice over the
heap; she inspects the lie of the land from above and selects a point
easy of access. Whoosh! She pounces upon it, digs with her head and
legs and forthwith makes her way in. Which way will she go?
At first the sense of hearing tells us of the direction followed: we
hear a rustling of withered leaves as long as the insect is working
through the dry outer layer. Then nothing but silence: the Cetonia has
reached the moist centre of the heap. Here and here only must the
laying take place, so that the grub emerging from the egg may find soft
food at hand without seeking for it. Let us leave the mother to her
task and return a couple of hours later.
But first let us reflect upon what has just occurred. A magnificent
insect, a living gem of goldsmith’s work, was slumbering just now at
the heart of a rose, on the satin of its petals, in the sweetness of
its scent. And now this voluptuary in her golden tunic, this sipper of
ambrosia, suddenly leaves her flower and buries herself in corruption;
she abandons the sumptuous hammock, fragrant of attar, to burrow in
nauseous filth. Whence this sudden depravity?
She knows that her grub will regale itself on what she herself abhors;
and overcoming her repugnance, not even giving it a thought, she takes
the plunge. Is she actuated by the memory of her larval days? But what
memory of food can she have after a year’s interval, above all after an
absolute remoulding of her organism? To draw the Cetonia hither, to
make her come from the rose to this putrid heap, there is something
better than the memory of the belly; there is a blind, irresistible
impulse, which acts in the most logical manner under cover of a seeming
insanity.
Let us now return to the heap of leaf-mould. The rustle of the withered
leaves has informed us approximately: we know in what direction to make
our search, a minute and hesitating search, for we have to follow the
mother’s trail. Nevertheless, guided by the materials thrust aside on
the insect’s passage, we reach our goal. The eggs are found, scattered
without order, always singly, with no preparatory measures. It is
enough that there should be close at hand soft vegetable matter,
suitably fermented.
The egg is an ivory globule, departing only slightly from the spherical
form and measuring nearly three millimetres [10] in diameter. The
hatching takes place twelve days later. The grub is white, bristling
with short, sparse hairs. When laid bare and removed from its
leaf-mould, it crawls upon its back, that is to say, it possesses the
curious method of locomotion characteristic of its race. With its
earliest wriggles it proclaims the art of walking on its back, with its
legs in the air.
Nothing is easier than to rear this grub. A thin box, which hinders
evaporation and keeps the provisions fresh, receives the nursling
together with a selection of fermented leaves, gathered from the heap
of mould. This is enough: my charge thrives and undergoes its
transformation in the following year, provided I take care to renew the
victuals from time to time. No entomological rearing gives less trouble
than that of the Cetonia-larva, with its robust appetite and its
vigorous constitution.
Its growth is rapid. At the beginning of August, four weeks after
hatching, the grub has reached half its final size. The idea occurs to
me to estimate its consumption of food by means of the stercoral
granules which collect in the box from the time of its first mouthful.
I find, 11,978 cubic millimetres; [11] that is to say, in one month the
grub has digested a volume of matter equivalent to several thousand
times its own initial bulk.
The Cetonia-grub is a mill that is always grinding dead vegetable
substances into meal; it is a crushing-machine of great efficiency,
which night and day, almost all the year round, shreds and powders the
matter which fermentation has already reduced to tatters. In the
rotting heap the fibres and veins of the leaves would remain intact
indefinitely. The grub takes possession of these refractory remnants;
with its excellent shears it tears and minces them very small; it
dissolves them, reducing them to a paste in the intestines, and adds
them, henceforth capable of being used, to the riches of the soil.
In the larval stage, the Cetonia is a most active manufacturer of
leaf-mould. When the metamorphosis occurs and I review the results of
my insect-rearing for the last time, I am shocked by the amount of
eating which my gormandizers have done in the course of their lives; it
can be measured by the bowlful.
The Cetonia-larva is worth attention from another point of view. It is
a corpulent grub, an inch long, with a convex back and a flat belly.
The dorsal surface is wrinkled with thick folds, on which the sparse
hairs stand erect like the bristles of a brush; the ventral surface is
smooth, covered with a fine skin, through which the ample wallet of
ordure shows as a brown patch. The legs are very well-shaped, but are
small, feeble and out of proportion to the rest of the body.
The creature is given to coiling itself into a closed ring. This is a
posture of repose, or rather of anxiety and defence. At such times the
living coil contracts so violently that we fear to see it burst open
and void its entrails when we seek to unroll it by force. When no
longer molested, the grub unrolls itself, straightens out and makes
haste to escape.
Then a surprise awaits us. If placed upon the table, the harassed
creature travels on its back with its legs in the air, inactive. This
extravagant method, contrary to the accepted usages of locomotion,
appears at first sight an accident, a chance manœuvre of the bewildered
animal. Not at all: it is a normal manœuvre; and the grub knows no
other. You turn it over on its belly, hoping to see it progress in the
customary fashion. Your attempts are useless: obstinately it lies down
on its back again, obstinately it crawls along in a reversed position.
Nothing will persuade it to walk on its legs. Either it will remain
motionless, coiled into a circle, or, straightening itself out, it will
travel upside down. This is its way of doing things.
Leave it undisturbed on the table. It sets off, longing to bury itself
in the soil and escape from its tormentor. Its progress is by no means
slow. The dorsal pads, actuated by a powerful layer of muscle, give it
a hold even on a smooth surface, thanks to their brush-like tufts of
hair. They are ambulacra which, by their multiplicity, exert a vigorous
traction.
The moving mechanism is apt to roll from side to side. By reason of the
rounded form of the back, the grub sometimes turns turtle. The accident
is not serious. With a heave of its loins, the capsized grub at once
recovers its balance and resumes its dorsal crawl, accompanied by a
gentle swaying to right and left. It also pitches to and fro. The prow
of the vessel, the larva’s head, rises and falls in measured
oscillations. The mandibles open and bite at space, apparently trying
to seize some support which is lacking.
Let us give it this support: not in the leaf-mould, whose opacity would
hide what I want to see, but in a transparent medium. I happen to have
what I need, a glass tube of some length, open at both ends and of a
gradually diminishing calibre. At the large end the grub enters
comfortably; at the other end it finds a very tight fit.
As long as the tube is more than wide enough, the grub moves along on
its back. Then it enters a part of the tube whose calibre is equal to
that of its body. From this moment the locomotion loses its abnormal
character. No matter what its position, whether the belly is uppermost,
undermost or to one side, the grub advances. I see the muscular waves
of the dorsal pads moving with a beautiful regularity, like the ripples
spreading over a calm sheet of water which has been disturbed by the
fall of a pebble. I see the bristles bowing and standing up again like
corn waving in the wind.
The head oscillates evenly. The tips of the mandibles are used as a
crutch which measures the paces in advance and gives stability by
obtaining a purchase of the walls. In all the positions, which I vary
at will by turning the tube between my fingers, the legs remain
inactive even when they touch the supporting surface. Their part in
locomotion is almost nil. What use, then, can they be? We shall see
presently.
The transparent channel in which the larva is worming its way tells us
what happens in the heart of the heap of garden-mould. Supported on
every side at once, close-sheathed in the substance traversed, the grub
progresses in the normal position as often as in the reversed position
and even oftener. By virtue of its dorsal waves, which come into
contact with the surrounding materials in every direction, it moves
back or belly uppermost, indifferently. Here are no longer fantastic
exceptions; matters return to their habitual order; if we could see the
grub ambling through the heap of rotting leaves, we should not regard
it as in any way peculiar.
But, when we expose it on the table, we perceive a glaring anomaly,
which disappears upon reflection. Support is lacking on every side save
from below. The dorsal pads, the principal ambulacra, take contact with
this one surface; and the animal straightway walks upside down. The
Cetonia-grub surprises us by the strangeness of its locomotion merely
because we are observing it outside its usual environment. It is thus
that the other corpulent, short-legged grubs would travel—the grubs of
the Cockchafer, the Oryctes [12] or the Anoxia-beetle—were it possible
to unroll them entirely and to straighten out the crook of their mighty
paunches.
In June, which is laying-season, the old larvæ that have lived through
the winter make their preparations for the transformation. The nymphal
caskets are contemporary with the ivory globules from which the new
generation will emerge. Although rudely made, the Cetonia-cocoons are
not without a certain elegance. They are ovoids almost the size of a
Pigeon’s egg. Those of the Funeral-pall Cetonia, the smallest of the
species inhabiting my heap of leaf-mould, are very much smaller, hardly
larger than a cherry.
All, however, have the same shape and the same appearance, so much so
that, with the exception of the small cocoons of the Funeral-pall
Cetonia, I cannot distinguish one from the other. Here the work tells
me nothing of the worker; I must wait until the adults come out to name
my discoveries correctly. However, as a general rule, subject to many
exceptions, the cocoons of the Golden Cetonia have an outside facing of
the insect’s droppings, set close together without any definite
arrangement. Those of the Metallic Cetonia and the Dark-brown Cetonia
are covered with remnants of decayed leaves.
We must regard these differences as resulting merely from the materials
that surround the grub at the moment when it is building its cocoon and
not from a special method of construction. It seems to me that the
Golden Cetonia likes building in the midst of its old dejecta, now hard
granules, while the other two prefer cleaner spots. Hence, no doubt,
the diversity of the outer layer.
In the case of the three larger Cetoniæ, the cocoons are free, that is
to say, they do not adhere to a fixed base; they are constructed
without a special foundation. The Funeral-pall Cetonia has other
methods. If it finds in the leaf-mould a little stone, no larger than a
finger-nail, it will by preference build its hut on this; but, if there
is no little stone, it can quite well dispense with it and build as the
others do, without any firm support.
The inside of the cocoon is smooth as stucco, as is required by the
delicate skin first of the grub, then of the nymph. The wall is tough,
resisting the pressure of the finger. It consists of a brown,
homogeneous material, of a nature which at first is difficult to
determine. It must have been a smooth paste which the grub worked in
its own fashion, even as the potter works his clay.
Does the ceramic art of the Cetonia likewise employ some sort of
fuller’s earth? So we should judge from the books, which agree in
regarding the cocoons of the Cockchafer, the Oryctes, the Cetonia and
other Beetles as earthy structures. The books, which are generally
compilations and not collections of facts directly observed, do not
inspire me with much confidence. In this instance my doubts are
increased, for the Cetonia-larva could not find the necessary clay
within a short radius, in the midst of the decayed leaves around it.
I myself, digging this way and that in the heap, should be greatly put
to it to collect enough plastic material to fill a thimble. What of the
grub, which no longer stirs from its place when the time has come to
shut itself up in a cocoon? It can gather only immediately around it.
And what does it find? Solely remains of leaves, humus, a bad mortar
that does not set. The conclusion is inevitable: the grub must have
other resources.
To divulge these resources will perhaps expose me to the foolish
accusation of unblushing realism. Certain ideas shock us though they
are quite straightforward and consistent with the sacred simplicity of
things. Nature has not our scruples: she makes direct for her goal,
heedless of our approval and our dislike. Let us silence a delicacy
which seems out of place: we must ourselves become animals to a certain
small extent, if we wish to understand the beautiful economy of animal
industry. Let us gloss over things as best we can, but let us not
shrink from the truth.
The Cetonia-larva is about to build itself a strong-box in which the
transformation, the most delicate of tasks, will be accomplished; it is
about to erect itself an enclosing wall, I might almost say, to spin
itself a cocoon. The caterpillar, to weave its cocoon withal, has
silk-tubes and a spinneret. The Cetonia-larva, which cannot make use of
outside things, has nothing at all, it would seem. But this is a
mistake. Its poverty is only apparent. Like the caterpillar, it has
secret reserves of building-materials; it has even a spinneret, but at
the other end of its body. Its store of cement is its intestine.
The grub was a mighty evacuator in its active period, as is proved by
the brown granules which it has scattered in profusion along its road.
As the transformation approached, it became more moderate; it began to
save up, amassing a hoard of paste of a most fine and binding quality.
Observe the tip of its belly as it withdraws from the world. You will
see a wide dark patch. This is the bag of cement showing through its
skin. This store, so well provided, tells us plainly in what the
artisan specializes: the Cetonia-larva works exclusively in fæcal
masonry.
If proofs were needed, here they are. I isolate some larvæ which have
attained their full maturity and are ready to build, in small jars,
placing one in each. As building needs a support, I provide each jar
with some slight contents, which can easily be removed. One receives
some cotton-wool, chopped small with the scissors; another some bits of
paper, the size of a lentil; a third some parsley-seed; a fourth some
radish-seed. I use whatever comes to hand, without preference for this
or that.
The larvæ do not hesitate to bury themselves in these surroundings,
which their race has never frequented. There is here no earthy matter,
such as we should expect to find used in the construction of the
cocoons; there is no clay to be collected. Everything is perfectly
clean. If the grub builds, it can only do so with mortar from its own
factory. But will it build?
To be sure it will and supremely well. In a few days’ time I have
magnificent cocoons, as strong as those that I extracted from the
leaf-mould. They are, moreover, much prettier in appearance. In the
flask containing cotton-wool, they are clad in a fluffy fleece; in that
containing bits of paper, they are covered with white tiles, as though
they had been snowed upon; in those containing radish or parsley-seed
they have the look of nutmegs embellished with an accurate milling.
This time the work is really beautiful. When human artifice assists the
talent of the stercoral artist, the result is a pretty toy.
The outer wrapper of paper scales, seeds or tufts of cotton-wool
adheres fairly well. Beneath it is the real wall, consisting entirely
of brown cement. The regularity of the shell gives us at first the idea
of an intentional arrangement. The same idea occurs to us if we
consider the cocoon of the Golden Cetonia, which is often prettily
adorned with a rubble of droppings. It looks as though the grub
collected from all around such building-stones as suit its purpose and
encrusted them piecemeal in the mortar to give greater strength to the
work.
But this is not so at all. There is no mosaic-work. With its round rump
the larva presses back the shifting material on every side; it adjusts
it, levels it by simple pressure and then fixes it, at one point after
another, by means of its mortar. Thus it obtains an egg-shaped cavity
which it reinforces at leisure with fresh layers of plaster, until its
excremental reserves are exhausted. Everything that is reached by the
trickling of the cement sets like concrete and henceforth forms part of
the wall, without any further intervention by the builder.
To follow the grub through the whole course of its labours is
impracticable: it works under a roof, protected from our indiscretion.
But we can at least surprise the essential secret of its method. I
select a cocoon whose softness indicates that the work is not yet
completed. I make a moderate hole in it. If it were too wide, the
breach would discourage the occupant and would make it impossible for
the grub to repair its shattered roof, not for lack of materials, but
for want of support.
Let us make a cautious incision with the point of a penknife and look.
The grub is rolled into a hook which is almost closed. Feeling uneasy,
it puts its head to the sky-light which I have opened and investigates
what has happened. The accident is soon perceived. Thereupon the hook
closes entirely, the opposite poles of the grub come into mutual
contact and then and there the builder is in possession of a pellet of
cement which the stercoral factory has that moment furnished. To
display such prompt obedience the intestine must certainly be
peculiarly obliging. That of the Cetonia-larva is very highly so;
directly it is called upon to act, it acts.
Now the true function of the legs is revealed. Of no use for walking,
they become precious auxiliaries when the time comes for building. They
are tiny hands that seize the piece gathered by the mandibles, turn it
over and over, and hold it while the mason subdivides it and applies it
economically. The pincers of the mandibles serve as a trowel.
They cut bit after bit from the lump, chewing and kneading the material
and then spreading it on the edge of the breach. The forehead presses
and smooths it as it is laid. When the supply of the moment is
exhausted, the grub, coiling itself again into a closed hook, will
obtain a further piece from its warehouse, which remains obedient to
its orders.
The little that the breach allows us to see—for it is pretty quickly
repaired—tells us what goes on under ordinary conditions. Without the
aid of sight, we see the grub evacuating at intervals and renewing its
store of cement; we can follow it as it gathers the clod with the tips
of its mandibles, squeezing it with its legs, dividing it to its liking
and spreading it with its mouth and forehead on the weak spots of the
wall. A rolling motion of the rump gives it a polish. Without borrowing
any extraneous materials, the builder finds within itself the
building-stones of its edifice.
A similar stercoral talent is the portion of other big-bellied larvæ,
which wear around their abdomen a wide brown sash, the insignia of
their craft. With the contents of their intestinal wallet they build
the hut in which metamorphosis takes place. All tells us of the high
economy which knows the secret of turning the abject into the decent
and of producing from a box of ordure the Golden Cetonia, the guest of
the roses and the glory of the spring.