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 [62]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 [63]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 [64]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 [65]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 [66]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 [67]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 [68]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 [69]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.[70]

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 [71]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 [72]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 [73]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 [74]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 [75]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,1 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 [76]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 [77]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 [78]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.[79]

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 [80]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. [81]They measure three centimetres2 in length, their breadth where they are widest being about fifteen millimetres.3 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 [82]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 [83]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.