THE PELOPÆUS
Of the several insects that elect to make their home in our houses,
certainly the most interesting, for the beauty of its shape, the
singularity of its manners and the structure of its nests, is the
Pelopæus, a Wasp hardly known even to the people whose fireside she
frequents. Her solitary habits and her peaceful occupation of the
premises explain why history is silent in her regard. She is so
extremely retiring that her host is nearly always ignorant of her
presence. Fame is for the noisy, the importunate, the noxious. Let us
try to rescue the modest creature from oblivion. An extremely chilly
mortal, the Pelopæus pitches her tent under the kindly sun which ripens
the olive and prompts the Cicada’s song; and even then she needs for
her family the additional warmth furnished by our dwellings. Her usual
refuge is the peasant’s lonely cottage, with its old fig-tree shading
the well in front of the door. She chooses one exposed to all the heat
of summer and, if possible, boasting a capacious fireplace in which a
fire of sticks is frequently renewed. The cheerful blaze on winter
evenings, when the sacred yule-log burns upon the hearth, is largely
responsible for her choice, for the insect knows by the blackness of
the chimney that the spot is a likely one. A chimney that is not well
glazed by smoke does not inspire her with confidence: people must
shiver with cold in that house.
During the dog-days in July and August, the visitor suddenly appears,
seeking a place for her nest. She is in no wise disturbed by the bustle
and movement of the household: they take no notice of her nor she of
them. Spasmodically she examines, now with her sharp eyes, now with her
sensitive antennæ, the corners of the blackened ceiling, the angles of
the rafters, the chimneypiece, the sides of the fireplace in particular
and even the interior of the flue. Having finished her inspection and
duly approved of the site, she flies away, soon to return with the
little pellet of mud which will form the first layer of the edifice.
The spot which she adopts varies greatly; often it is an extremely
curious one, the one positive condition being that the temperature
should be mild and equable. A furnace heat appears to suit the
Pelopæus’ larvæ; at least, the favourite place is the chimney, on
either side of the flue, up to a height of twenty inches or so. This
snug shelter has its drawbacks. The smoke gets to the nests, especially
during the winter, when fires are going all day, and gives them a glaze
of brown or black similar to that which covers the stonework. They are
so like it in appearance that they might well be taken for inequalities
in the mortar which have been overlooked by the trowel. This swarthy
distempering is not a serious matter, provided that the flames do not
lick against the cluster of cells. That would ensure the destruction of
the larvæ, stewed to death in their clay pots. But this danger appears
to be foreseen; and the Pelopæus entrusts her family only to chimneys
which are too wide for anything but smoke to reach their sides; she is
suspicious of the narrow ones which allow the flames to fill the whole
entrance to the flue.
In spite of her caution, one peril remains. While the nest is building,
at a moment when the Wasp, urged by the need for laying her eggs,
cannot bring herself to cease working, it sometimes happens that the
approach to the dwelling is barred to her for a time, or even for the
whole day, either by a curtain of steam rising from a stew-pan or by
clouds of smoke resulting from damp firewood. Washing-days are the most
risky. From morning to night, the housewife keeps the huge cauldron
boiling with all the odds and ends of the wood-shed: chips, bits of
bark, leaves, fuel that burns with difficulty and intermittently. The
smoke from the hearth, the steam from the cauldron and the reek from
the wash-tub form in front of the fireplace a dense mist with very few
rifts in it. I have at rare intervals surprised the Pelopæus in the
presence of some such obstacle.
It is told of the Water-ouzel, the Dipper, that, to get back to his
nest, he will fly through the cataract under a mill-weir. The Pelopæus
is even more daring: with her pellet of mud in her teeth, she crosses
the cloud of smoke and disappears behind it, henceforth invisible, so
thick is the screen. A spasmodic chirring, her working-song, alone
betrays the mason at her task. The building rises mysteriously behind
the cloud. The ditty ceases and the Wasp emerges from the steam-flakes,
fit and well, as though coming out of a limpid atmosphere. She has
faced the fire, like the fabled Salamander, and she will face it all
day, until the cell is built, crammed with victuals and closed.
Cases of this kind occur too seldom to satisfy fully the curiosity of a
seasoned observer. I should have liked to arrange the mist-screen
myself and thus to try a few experiments bearing upon the dangerous
crossing; but I was a stranger, a spectator by sheer chance; and all
that I could do was to trust to luck, without interfering with the
washing-operations and perhaps upsetting them. What a sorry idea the
housewife engaged on that grave business would have had of my
intelligence if I had ventured to touch her fire in order to worry a
Wasp!
“I’a pétan cièucle: little things please little minds,” she would have
been sure to think.
In the eyes of the peasant, to occupy one’s self with such small fry is
a lunatic’s game, the amusement of a cracked mind.
Once and once only fortune smiled upon me; but I was not ready to
profit by it. The thing took place at my own house, by my own fireside
and, as it happened, on a washing-day. I had not long been appointed to
the Avignon grammar-school. It was close upon two o’clock; and in a few
minutes the roll of the drum would summon me to display the properties
of the Leyden jar to an audience of wool-gatherers. I was preparing to
start, when I saw a strange, agile insect, with a slender body and a
gourd-shaped abdomen slung at the end of a long thread, dart through
the reek rising from the wash-tub. It was the Pelopæus, whom I saw for
the first time with observant eyes. A novice still and anxious to
become better-acquainted with my visitor, I fervently commended the
insect to the watchful care of the household, begging them not to
disturb it in my absence and to manage the fire in such a way as not to
inconvenience it in its plucky work of building the walls of its nest
right beside the flame. My wishes were carried out religiously.
Things went better than I dared hope. On my return, the Pelopæus was
continuing her mason’s work behind the steam of the wash-tub, which
stood under the mantel of a wide chimney. Eager as I was to witness the
construction of the cells, to identify the nature of the provisions, to
follow the evolution of the larvæ, all of them biological details
entirely new to me, I took good care not to raise the experimental
obstacles which I should not fail to set in the path of instinct
to-day: a good nest was the sole object that I coveted. Therefore, so
far from creating fresh difficulties for the Pelopæus, I did my utmost
to reduce those which she had to overcome. I raked the fire, making it
much smaller, so as to decrease the volume of smoke in the Wasp’s
building-yard; and for a good two hours I watched her diving through
the cloud. Next day, the usual niggardly fire was burning
intermittently; and there was nothing now to hamper the Pelopæus, who
continued her work for some days and without further impediment
completed the well-filled nest which was the object of my wishes.
Never again, in the forty years that followed, was my fireplace
honoured with such a visit; and it was only by having recourse to the
more fortunate hearths of my neighbours that I was able to glean my
little bit of information. Nor was it until much later that, profiting
by long experience, I had the idea of turning to account the
predilection of so many Bees and Wasps for their birthplace and for
founding a family in the neighbourhood of the nest where they receive
perhaps the strongest of all impressions, the first dawn of light. I
took Pelopæus-nests which I had collected more or less everywhere
during the winter and fixed them in different places, in my present
house, which, judging by the sum total of my observations, I considered
suitable, notably at the entrance to the chimney both of the kitchen
and of the study. I put some in the embrasures of the windows, keeping
the outside shutters closed to obtain the requisite sultriness; I stuck
some to the dimly-lighted corners of the ceilings. It was in these
sites of my choosing that the new generation was to hatch when summer
came; it was here that it would settle: at least I thought so. Then I
could have conducted in my own way the experiments which I had in mind.
My attempts invariably failed. Not one of my charges returned to the
native nest; the less fickle of them contented themselves with brief
visits, soon followed by a departure for good. The Pelopæus, it
appears, is of a solitary and vagrant disposition: save in
exceptionally favourable circumstances, she builds a lonely nest and is
quite ready to change her locality from generation to generation. As a
matter of fact, though this Wasp is fairly common in my village, her
dwellings are nearly always scattered one by one, with no traces of any
old nests near by. The place of her birth leaves no lasting
recollection in the nomad’s memory; and none comes to build beside the
ruins of the maternal home.
For that matter, my want of success might well be due to another cause.
The Pelopæus certainly is not rare in our southern towns; nevertheless
she prefers the peasant’s smoky house to the townsman’s white villa.
Nowhere have I seen her so plentiful as in my village, with its
tumbledown cottages guiltless of rough-cast and burnt yellow by the
sun. My hermitage is not quite so rustic as that: it is a little neater
and cleaner; and there is nothing to show that my visitors did not
forsake my kitchen and my study, both too sumptuous in their opinion,
to go and settle somewhere near in lodgings more to their taste. And so
the eagerly desired colonists, who were to have peopled my workroom
crammed with books, plants, fossils and entomological cemeteries, took
their departure, scorning all that scientific luxury; they went away in
search of some dim chamber with a solitary window sporting a sprig of
wall-flower in an old, cracked stew-pot. Felicities like that are
reserved for the humble; and I am therefore reduced to what I have
gained by an occasional piece of good luck, irrespective of any efforts
of mine. The little that I have seen, in one direction and another, is
after all sufficient evidence of the pluck of the Pelopæus, who, to
reach her nest built in a corner of the hearth, at times passes through
a cloud of steam and smoke. Would she dare to cross a thin sheet of
flame? That was what I had proposed to see, if my attempts to
acclimatize her in my home had met with any success.
It is obvious that, in displaying a marked predilection for the chimney
as her abode, the Pelopæus is not seeking her own comfort: the site
chosen means work and dangerous work. She seeks the welfare of her
family. This family then, in order to prosper, must require a high
temperature, such as is not demanded by the other Wasps or Bees, the
Chalicodoma and the Osmia, for instance, who find sufficient shelter
under a mortar dome or in the hollow of an exposed reed. Let us see
what temperature the Pelopæus finds to her liking.
On the side-wall, under the chimneypiece, I hung a thermometer over a
Pelopæus-nest. During an hour’s observation, with a fire giving out a
moderate heat, it fluctuated between 95° and 105° F. This temperature,
it is true, does not remain the same during the long larval period; on
the contrary, it varies greatly, according to the season of the year
and the time of day. I wanted something better and I found it on two
occasions.
My first observation was made in the engine-room of a silk-factory. The
back of the boiler reached nearly to the ceiling, the space between
being barely twenty inches. It was against this ceiling, right above
the huge cauldron, which was always full of water and steam at a high
temperature, that the Pelopæus-nest was fixed. At this spot the
thermometer marked 120°. This degree of heat was maintained all through
the year; it was only at night and on holidays that it decreased.
A country distillery furnished me with the second subject of
observation. It combined two excellent conditions for attracting
Pelopæi: rural quiet and the heat of a furnace. The nests therefore
were numerous, fixed more or less everywhere on anything that came to
hand, even down to the pile of account-books in which the excisemen
registered their troublesome inspections of the proof-spirit. One of
these, situated quite close to the still, was tested with the
thermometer. It measured 113° of heat.
These few data prove that the larvæ of the Pelopæus are comfortable in
a temperature of a hundred degrees or over, a temperature not
accidental, like that produced by a fire blazing in a chimney, but
constant, such as obtained by a boiler or a still. Tropical heat is
favourable to the grub slumbering for ten months in its mud hole. Any
seed, in order to sprout, needs a certain quantum of heat, greater or
smaller according to its kind. The larva, a sort of animal seed out of
which the perfect insect will come by a process of germination even
more wonderful than that which turns an acorn into an oak, the larva
also claims its quantum of heat. The larva of the Pelopæus can
cheerfully endure a temperature that makes the baobab or the oily
palm-tree sprout. What then is the origin of this chilly tribe?
A good fire on the hearth, a boiler or a furnace shedding an artificial
tropical climate around them are useful windfalls, which, however,
cannot be relied upon; and the Pelopæus settles in any lodging where
she finds warmth and not too garish a light. The corners of a
conservatory; a kitchen-ceiling; the embrasure of a window with closed
casement and shutters, provided that these furnish some exit-hole; the
rafters of a loft, where the warmth of the daily quota of sunshine is
preserved by the heaped-up hay and straw; the walls of a cottage
bedroom: any of these suit her, so long as the larvæ find a snug
shelter in winter. This climatological expert, the daughter of the
dog-days, divines the coming peril for her family, that inclement
season which she herself will never see.
While she is scrupulous in her choice of a warm spot, on the other hand
she is supremely indifferent to the nature of the foundation on which
the nest is to be fastened. As a rule, she fixes her groups of cells to
the stonework, whether rough-coated or not, and to the timber, whether
bare or plastered; but she uses many other supports, some of which are
very peculiar. Let us mention a few of these fantastic installations.
My notes speak of a nest constructed inside a gourd standing on the
mantelpiece of a farm-kitchen. In this narrow-mouthed receptacle the
farmer used to keep his shot. As the orifice was always open and the
utensil not employed at that time of year, a Pelopæus had found that
the peaceful retreat suited her and had gone to the length of building
on the layer of small-shot. The gourd had to be broken to extract the
bulky edifice.
The same notes tell me of nests built against the pile of account-books
in a distillery; in a fur cap relegated to the wall until the return of
winter; in the hollow of a brick, back to back with the downy structure
of a Cotton-bee; on the sides of a bag of oats; in a piece of lead
tubing broken off from an old water-pipe.
I saw something more remarkable still in the kitchen at Roberty, one of
the biggest farms near Avignon. It was a large room with a very wide
fireplace, in which the soup for the farm-hands and the food for the
cattle were simmering in a row of pots and pans. The labourers used to
come in from the fields so many at a time, take their seats on benches
round the table and devour the portions served to them, with the silent
haste that denotes a keen appetite. To enjoy this half-hour of comfort,
they would take off their hats and smocks and hang them on pegs on the
wall. Short though the meal was, it lasted long enough to allow the
Pelopæi to inspect the garments and take possession of them. The inside
of a straw hat was recognized as a most useful retreat; the folds of a
smock were looked upon as a shelter which could be turned to excellent
account; and the work of building started forthwith. On rising from
table, one of the men would shake his smock, another his hat, to rid it
of a heap of mud that was already the size of an acorn.
When the labourers had gone, I had a talk with the cook. She told me of
her tribulations: those impudent Bugs were all over the place, dirtying
everything with their filth. She was chiefly concerned about the
window-curtains. Dabs of mud on the ceiling, on the walls, on the
chimneypiece you could put up with; but it was a very different matter
when you found them on the linen and the curtains. To keep the curtains
clean and dislodge the wretched things who persisted in bringing in
their bits of mud, she had to shake them every day, to beat them with a
bamboo. And it was all no use: next morning, work was resumed with
equal vigour on the buildings destroyed the day before.
I sympathized with her sorrows, while greatly regretting that I could
not myself take charge of the place. How gladly I would have left the
Pelopæi undisturbed, though they covered every scrap of upholstery with
mud; how willingly I would have let them have their way, so that I
might learn what prospects there are for a nest if perched on the
shifting support of a coat or a curtain! The Mason-bee of the Shrubs,
[28] heedless of the storm, builds on a twig; but her edifice,
constructed of hard mortar, envelops the support, surrounds it on every
side and becomes firmly fixed to it. The nest of the Pelopæus is a mere
blob of mud, fastened to its support without any special adhesive
preparation. It has no hydraulic cement which sets as soon as used, no
foundations welded to the supporting base. How can such a method give
proper stability? The nests which I find on the coarse canvas of
corn-bags come off at the least shake, though the rough mesh of the
stuff makes it easier for them to stick on: what will happen when the
nests are placed on a piece of fine calico hanging perpendicularly and
often flicked about, if only by the draught? To build on that strikes
me as an aberration of instinct on the part of the architect, who has
not yet learnt, in spite of the long lesson of the ages, how perilous
are certain sites in human habitations.
Let us leave the constructor and occupy ourselves with the structure.
The materials consist exclusively of wet earth, mud or dirt, picked up
wherever the soil possesses the proper degree of humidity. When there
is a stream in the neighbourhood, the thin clay of the banks is turned
to account. But cement-works of this sort are rare or too far off in my
stony region; and it is not in such a building-yard that I most
frequently witness the gathering of the materials. I can watch the
performance at my leisure without leaving my own garden. When a thin
trickle of water runs from morning till evening in the little trenches
cut in the vegetable-plots, a few Pelopæi, visitors to the neighbouring
farms, soon get wind of the glad event. They come hurrying up to take
advantage of the precious layer of mud, a rare discovery in this
distressing time of drought. One selects a recently-watered furrow,
another prefers to keep on the bank and settle in a work-yard moistened
by capillary action. They scrape and skim the gleaming, slimy surface
with their mandibles while standing high on their legs, with wings
aquiver and their black abdomen upraised on its yellow pedicel. No neat
little housewife, with skirts carefully tucked out of the dirt, could
be more adept in tackling a job so prejudicial to the cleanliness of
her clothes. These mud-gatherers have not an atom of soil upon them, so
careful are they to tuck up their skirts in their fashion, that is to
say, to keep their whole body out of the way, all but the tips of their
legs and the busy points of their mandibles. In this manner a dab of
mud is collected, almost the size of a pea. Taking the load in its
teeth, the insect flies off, adds a layer to its building and soon
returns to collect another pellet. The same work is pursued as long as
the earth remains sufficiently wet, during the hottest hours of the
day, for there is always some builder looking about for mortar.
But the most frequented spot is in front of the great fountain in the
village. Here there is a large trough where the people round about come
to water their Mules. The constant trampling of the heavily-laden
quadrupeds and the overflow of the water create a perpetual sheet of
black mud which neither the heat of July nor the mighty blast of the
mistral succeeds in drying. This bed of mire, so unpleasant for the
passers-by, is beloved of the Pelopæi, who meet there from every part
of the neighbourhood. You seldom pass before the noisome puddle without
seeing some of them gathering their pellets amid the hoofs of the Mules
slaking their thirst.
The places exploited are enough in themselves to tell us that the
mortar is collected ready-made, fit for immediate use without any
further preparation than a vigorous kneading which gets rid of the
lumps and makes the whole into a homogeneous mass. Other builders in
clay, the Mason-bees, for instance, scrape up the dust on the highway
and moisten it with saliva to convert it into a plastic material which
will harden like stone by virtue of certain chemical properties of the
salivary fluid. They set to work like the bricklayer, who mixes his
mortar and his plaster by adding water in small quantities. The
Pelopæus does not practise this art; the secret of chemical action is
denied her; and the mud is employed just as it is picked up.
To make sure of this, I stole a few pellets from the busy collectors
and, on comparing them with other pellets gathered in the same place
and rolled by my own fingers, found no difference between them in
appearance or in properties. The result of this comparison is confirmed
by an examination of the nest. The structures of the Chalicodomæ are
solid masonry, capable of resisting without any protection the
prolonged action of rain and snow; those of the Pelopæi are flimsy
work, devoid of cohesion and absolutely unfitted to withstand the
vicissitudes of the open air. A drop of water laid upon their surface
softens the spot touched and reduces it to mud again, while a
sprinkling equal to an average shower turns it into pap. They are
nothing more than dried slime and become slime again as soon as they
are wetted.
The thing is obvious: the Wasp does not improve the mud to make it into
mortar; she uses it as it is. It is no less obvious that nests of this
sort are not made for out-of-doors, even if the larva were not of such
a chilly humour. A shelter that keeps them under cover is
indispensable, otherwise they would go to pieces at the first shower of
rain. This explains, apart altogether from questions of temperature,
why the Pelopæus has a preference for human habitations, which afford
the best protection against damp. Under the mantels of our chimneys she
finds at one and the same time the heat required by the larvæ and the
necessary dryness for the nests.
Before receiving its final coating, which conceals the structural
details, the Pelopæus’ edifice does not lack elegance. It consists of a
cluster of cells, sometimes arranged side by side in one row—which
gives the fabric something of the look of a mouth-organ with reeds all
short and all alike in size—but more often grouped in a varying number
of layers placed one above the other. In the most populous nests I
count as many as fifteen cells; others contain only about ten; others
again are reduced to three or four, or even to one alone. The first
appear to me to represent a mother’s whole output of eggs; the second
signify incomplete layings, deposited here and there, perhaps because
better sites were found elsewhere.
The cells are not far removed from the cylindrical shape, with a
diameter increasing slightly from the mouth to the base. They measure
three centimetres [29] in length, their breadth where they are widest
being about fifteen millimetres. [30] Their delicate surface, carefully
polished, shows a series of stringy projections, running obliquely, not
altogether unlike the twisted cords of certain kinds of gold-lace. Each
of these strings is a layer of the edifice; it comes from the clod of
mud employed on the coping of the part already built. By numbering them
one can tell how many journeys the Pelopæus has taken to her mortar. I
count between fifteen and twenty. For one cell, therefore, the
industrious builder fetches materials something like twenty times and
perhaps even oftener, for one of these cushions of mud is not always,
so it seems to me, completed in a single spell of work.
The main axis of the cells is horizontal, or not far removed from it;
the mouth is always turned upwards. And this must needs be so: a pot
cannot hold its contents save on condition that it be not upside down.
The Pelopæus’ cell is nothing more than a pot destined to receive the
preserved foodstuffs, a pile of small Spiders. When laid horizontally
or slanting a little upwards, the receptacle holds its contents; but
with the mouth turned downwards it would lose them. I have lingered a
moment over this petty detail to call attention to a curious mistake
current in the text-books. Wherever I find a drawing of a
Pelopæus-nest, I see it with the orifices of the cells facing
downwards. The illustrations go on and on: to-day’s reproduces
yesterday’s absurdity. I do not know who was the first to perpetrate
this blunder and to think of subjecting the Pelopæus to a task no less
arduous than that of the vessel of the Danaides: to fill a pot turned
upside down.
Built one by one, stuffed full of Spiders and closed as and when the
laying demands it, the cells retain their elegant exterior until the
cluster is deemed large enough. Then, to strengthen her work, the
Pelopæus covers the whole with a defensive casing; she lays on the
plaster with an unsparing trowel, without artistry or any of those
delicate and patient finishing-touches which she lavishes upon the work
of the cells. The pellet is applied just as it is brought and merely
spread with a few careless strokes of the mandibles. Thus the original
beauties of the structure—the flutings between the cells sat back to
back, the corded cushions, the polished stucco—all disappear under a
forbidding husk. In this final state, the nest is nothing more than a
shapeless protuberance; one would take it for a great splash of mud
that had been flung against the wall by accident and dried there.
We find similar methods among the Chalicodomæ. The best mason among
them, after she has erected her cells on a pebble, building them in the
form of turrets daintily encrusted with bits of gravel, buries her
artistic work under a clumsy plaster. Why do they both give this finish
and devote such fastidious care to the frontage, when the masterpiece
is doomed to disappear, deluged in mortar? We do not build a Louvre and
then abandon its colonnades to the unclean trowel. But we must not
press the analogy too far. What do insects care about the beauty or
ugliness of an edifice, provided that the larva be comfortably housed?
With them we must be prepared for all the inconsistencies of the
unconscious artist.