A rampart at the back of the Earth-worm's shaft is a wise precaution and the Leaf-cutter deserves all credit for it; only it is a pity for the Megachiles' reputation that this protective barrier often protects nothing at all. Here we see, under a new guise, that aberration of instinct of which I gave some examples in an earlier chapter. My notes contain memoranda of various galleries crammed with pieces of leaves right up to the orifice, which is on a level with the ground, and entirely devoid of cells, even of an unfinished one. These were ridiculous fortifications, of no use whatever; and yet the Bee treated the matter with the utmost seriousness and took infinite pains over her futile task. One of these uselessly barricaded galleries furnished me with some hundred pieces of leaves arranged like a stack of wafers; another gave me as many as a hundred and fifty. For the defence of a tenanted nest, two dozen and even fewer are ample. Then what was the object of the Leaf-cutter's ridiculous pile?

I wish I could believe that, seeing that the place was dangerous, she made her heap bigger so that the rampart might be in proportion to the danger. Then, perhaps, at the moment of starting on the cells, she disappeared, the victim of an accident, blown out of her course by a gust of wind. But this line of defence is not admissible in the Megachile's case. The proof is palpable: the galleries aforesaid are barricaded up to the level of the ground; there is no room, absolutely none, to lodge even a single egg. What was her object, I ask again, when she persisted in obstinately piling up her wafers? Has she really an object?

I do not hesitate to say no. And my answer is based upon what the Osmiae taught me. I have described above how the Three-horned Osmia, towards the end of her life, when her ovaries are depleted, expends on useless operations such energy as remains to her. Born a worker, she is bored by the inactivity of retirement; her leisure requires an occupation. Having nothing better to do, she sets up partitions; she divides a tunnel into cells that will remain empty; she closes with a thick plug reeds containing nothing. Thus is the modicum of strength of her decline exhausted in vain labours. The other Builder-bees behave likewise. I see Anthidia laboriously provide numerous bales of cotton to stop galleries wherein never an egg was laid; I see Mason-bees build and then religiously close cells that will remain unvictualled and uncolonized.

The long and useless barricades then belong to the last hours of the Megachile's life, when the eggs are all laid; the mother, whose ovaries are exhausted, persists in building. Her instinct is to cut out and heap up pieces of leaves; obeying this impulse, she cuts out and heaps up even when the supreme reason for this labour ceases. The eggs are no longer there, but some strength remains; and that strength is expended as the safety of the species demanded in the beginning. The wheels of action go on turning in the absence of the motives for action; they continue their movement as though by a sort of acquired velocity. What clearer proof can we hope to find of the unconsciousness of the animal stimulated by instinct?

Let us return to the Leaf-cutter's work under normal conditions. Immediately after a protective barrier comes the row of cells, which vary considerably in number, like those of the Osmia in her reed. Strings of about a dozen are rare; the most frequent consist of five or six. No less subject to variation is the number of pieces joined to make a cell: pieces of two kinds, some, the oval ones, forming the honey-pot; others, the round ones, serving as a lid. I count, on an average, eight to ten pieces of the first kind. Though all cut on the pattern of an ellipse, they are not equal in dimensions and come under two categories. The larger, outside ones are each of them almost a third of the circumference and overlap one another slightly. Their lower end bends into a concave curve to form the bottom of the bag. Those inside, which are considerably smaller, increase the thickness of the sides and fill up the gaps left by the first.

The Leaf-cutter therefore is able to use her scissors according to the task before her: first, the large pieces, which help the work forward, but leave empty spaces; next, the small pieces, which fit into the defective portions. The bottom of the cell particularly comes in for after-touches. As the natural curve of the larger pieces is not enough to provide a cup without cracks in it, the Bee does not fail to improve the work with two or three small oval pieces applied to the imperfect joins.

Another advantage results from the snippets of unequal size. The three or four outer pieces, which are the first placed in position, being the longest of all, project beyond the mouth, whereas the next, being shorter, do not come quite up to it. A brim is thus obtained, a ledge on which the round disks of the lid rest and are prevented from touching the honey when the Bee presses them into a concave cover. In other words, at the mouth the circumference comprises only one row of leaves; lower down it takes two or three, thus restricting the diameter and securing an hermetic closing.

The cover of the pot consists solely of round pieces, very nearly alike and more or less numerous. Sometimes I find only two, sometimes I count as many as ten, closely stacked. At times, the diameter of these pieces is of an almost mathematical precision, so much so that the edges of the disk rest upon the ledge. No better result would be obtained had they been cut out with the aid of compasses. At times, again, the piece projects slightly beyond the mouth, so that, to enter, it has to be pressed down and curved cupwise. There is no variation in the diameter of the first pieces placed in position, those nearest to the honey. They are all of the same size and thus form a flat cover which does not encroach on the cell and will not afterwards interfere with the larva, as a convex ceiling would. The subsequent disks, when the pile is numerous, are a little larger; they only fit the mouth by yielding to pressure and becoming concave. The Bee seems to make a point of this concavity, for it serves as a mould to receive the curved bottom of the next cell.

When the row of cells is finished, the task still remains of blocking up the entrance to the gallery with a safety-stopper similar to the earthen plug with which the Osmia closes her reeds. The Bee then returns to the free and easy use of the scissors which we noticed at the beginning when she was fencing off the back part of the Earth-worm's too deep burrow; she cuts out of the foliage irregular pieces of different shapes and sizes and often retaining their original deeply-indented margins; and with all these pieces, very few of which fit at all closely the orifice to be blocked, she succeeds in making an inviolable door, thanks to the huge number of layers.

Let us leave the Leaf-cutter to finish depositing her eggs in other galleries, which will be colonized in the same manner, and consider for a moment her skill as a cutter. Her edifices consist of a multitude of fragments belonging to three categories: oval pieces for the sides of the cells; round pieces for the lids; and irregular pieces for the barricades at the front and back. The last present no difficulty: the Bee obtains them by removing from the leaf some projecting portion, as it stands, a serrate lobe which, owing to its notches, shortens the insect's task and lends itself better to scissor-work. So far, there is nothing to deserve attention: it is unskilled labour, in which an inexperienced apprentice might excel.

With the oval pieces, it becomes another matter. What model has the Megachile when cutting her neat ellipses out of the delicate material for her wallets, the robinia-leaves? What mental pattern guides her scissors? What system of measurement tells her the dimensions? One would like to picture the insect as a living pair of compasses, capable of tracing an elliptic curve by a certain natural inflexion of its body, even as our arm traces a circle by swinging from the shoulder. A blind mechanism, the mere outcome of its organization, would alone be responsible for its geometry. This explanation would tempt me if the large oval pieces were not accompanied by much smaller ones, also oval, which are used to fill the empty spaces. A pair of compasses which changes its radius of its own accord and alters the curve according to the plan before it appears to me an instrument somewhat difficult to believe in. There must be something better than that. The circular pieces of the lid suggest it to us.

If, by the mere flexion inherent in her structure, the Leaf-cutter succeeds in cutting out ovals, how does she succeed in cutting out rounds? Can we admit the presence of other wheels in the machinery for the new pattern, so different in shape and size? Besides, the real point of the difficulty does not lie there. These rounds, for the most part, fit the mouth of the jar with almost exact precision. When the cell is finished, the Bee flies hundreds of yards away to make the lid. She arrives at the leaf from which the disk is to be cut. What picture, what recollection has she of the pot to be covered? Why, none at all: she has never seen it; she does her work underground, in utter darkness! At the utmost, she can have the indications of touch: not actual indications, of course, for the pot is not there, but past indications, useless in a work of precision. And yet the disk to be cut out must have a fixed diameter: if it were too large, it would not go in; if too small, it would close badly, it would slip down on the honey and suffocate the egg. How shall it be given its correct dimensions without a pattern? The Bee does not hesitate for a moment. She cuts out her disk with the same celerity which she would display in detaching any shapeless lobe that might do for a stopper; and that disk, without further measurement, is of the right size to fit the pot. Let whoso will explain this geometry, which in my opinion is inexplicable, even when we allow for memory begotten of touch and sight.

One winter evening, as we were sitting round the fire, whose cheerful blaze unloosed our tongues, I put the problem of the Leaf-cutter to my family:

'Among your kitchen-utensils,' I said, 'you have a pot in daily use; but it has lost its lid, which was knocked over and broken by the Tomcat playing among the shelves. To-morrow is market-day and one of you will be going to Orange to buy the week's provisions. Would she undertake, without a measure of any kind, with the sole aid of memory, which we would allow her to refresh before starting by a careful examination of the object, to bring back exactly what the pot wants, a lid neither too large nor too small, in short the same size as the top?'

It was admitted with one accord that nobody would accept such a commission without taking a measure with her, or at least a bit of string giving the width. Our memory for sizes is not accurate enough. She would come back from the town with something that 'might do'; and it would be the merest chance if this turned out to be the right size.

Well, the Leaf-cutter is even less well-off than ourselves. She has no mental picture of her pot, because she has never seen it; she is not able to pick and choose in the crockery-dealer's heap, which acts as something of a guide to our memory by comparison; she must, without hesitation, far away from her home, cut out a disk that fits the top of her jar. What is impossible to us is child's-play to her. Where we could not do without a measure of some kind, a bit of string, a pattern or a scrap of paper with figures upon it, the little Bee needs nothing at all. In housekeeping matters she is cleverer than we are.

One objection was raised. Was it not possible that the Bee, when at work on the shrub, should first cut a round piece of an approximate diameter, larger than that of the neck of the jar, and that afterwards, on returning home, she should gnaw away the superfluous part until the lid exactly fitted the pot? These alterations made with the model in front of her would explain everything.

That is perfectly true; but are there any alterations? To begin with, it seems to me hardly possible that the insect can go back to the cutting once the piece is detached from the leaf: it lacks the necessary support to gnaw the flimsy disk with any precision. A tailor would spoil his cloth if he had not the support of a table when cutting out the pieces for a coat. The Megachile's scissors, so difficult to wield on anything not firmly held, would do equally bad work.

Besides, I have better evidence than this for my refusal to believe in the existence of alterations when the Bee has the cell in front of her. The lid is composed of a pile of disks whose number sometimes reaches half a score. Now the bottom part of all these disks is the under surface of the leaf, which is paler and more strongly veined; the top part is the upper surface, which is smooth and greener. In other words, the insect places them in the position which they occupy when gathered. Let me explain. In order to cut out a piece, the Bee stands on the upper surface of the leaf. The piece detached is held in the feet and is therefore laid with its top surface against the insect's chest at the moment of departure. There is no possibility of its being turned over on the journey. Consequently, the piece is laid as the Bee has just picked it, with the lower surface towards the inside of the cell and the upper surface towards the outside. If alterations were necessary to reduce the lid to the diameter of the pot, the disk would be bound to get turned over: the piece, manipulated, set upright, turned round, tried this way and that, would, when finally laid in position, have its top or bottom surface inside just as it happened to come. But this is exactly what does not take place. Therefore, as the order of stacking never changes, the disks are cut, from the first clip of the scissors, with their proper dimensions. The insect excels us in practical geometry. I look upon the Leaf-cutter's pot and lid as an addition to the many other marvels of instinct that cannot be explained by mechanics; I submit it to the consideration of science; and I pass on.

The Silky Leaf-cutter (Megachile sericans, FONSCOL.; M. Dufourii, LEP.) makes her nests in the disused galleries of the Anthophorae. I know her to occupy another dwelling which is more elegant and affords a more roomy installation: I mean the old dwelling of the fat Capricorn, the denizen of the oaks. The metamorphosis is effected in a spacious chamber lined with soft felt. When the long-horned Beetle reaches the adult stage, he releases himself and emerges from the tree by following a vestibule which the larva's powerful tools have prepared beforehand. When the deserted cabin, owing to its position, remains wholesome and there is no sign of any running from its walls, no brown stuff smelling of the tan-yard, it is soon visited by the Silky Megachile, who finds in it the most sumptuous of the apartments inhabited by the Leaf-cutters. It combines every condition of comfort: perfect safety, an even temperature, freedom from damp, ample room; and so the mother who is fortunate enough to become the possessor of such a lodging uses it entirely, vestibule and drawing-room alike. Accommodation is found for all her family of eggs; at least, I have nowhere seen nests as populous as here.

One of them provides me with seventeen cells, the highest number appearing in my census of the Megachile clan. Most of them are lodged in the nymphal chamber of the Capricorn; and, as the spacious recess is too wide for a single row, the cells are arranged in three parallel series. The remainder, in a single string, occupy the vestibule, which is completed and filled up by the terminal barricade. In the materials employed, hawthorn-and paliurus-leaves predominate. The pieces, both in the cells and in the barrier, vary in size. It is true that the hawthorn-leaves, with their deep indentations, do not lend themselves to the cutting of neat oval pieces. The insect seems to have detached each morsel without troubling overmuch about the shape of the piece, so long as it was big enough. Nor has it been very particular about arranging the pieces according to the nature of the leaf: after a few bits of paliurus come bits of vine and hawthorn; and these again are followed by bits of bramble and paliurus. The Bee has collected her pieces anyhow, taking a bit here and there, just as her fancy dictated. Nevertheless, paliurus is the commonest, perhaps for economical reasons.

I notice, in fact, that the leaves of this shrub, instead of being used piecemeal, are employed whole, when they do not exceed the proper dimensions. Their oval form and their moderate size suit the insect's requirements; and there is therefore no necessity to cut them into pieces. The leaf-stalk is clipped with the scissors and, without more ado, the Megachile retires the richer by a first-rate bit of material.

Split up into their component parts, two cells give me altogether eighty-three pieces of leaves, whereof eighteen are smaller than the others and of a round shape. The last-named come from the lids. If they average forty-two each, the seventeen cells of the nest represent seven hundred and fourteen pieces. These are not all: the nest ends, in the Capricorn's vestibule, with a stout barricade in which I count three hundred and fifty pieces. The total therefore amounts to one thousand and sixty-four. All those journeys and all that work with the scissors to furnish the deserted chamber of the Cerambyx! If I did not know the Leaf-cutter's solitary and jealous disposition, I should attribute the huge structure to the collaboration of several mothers; but there is no question of communism in this case. One dauntless creature and one alone, one solitary, inveterate worker, has produced the whole of the prodigious mass. If work is the best way to enjoy life, this one certainly has not been bored during the few weeks of her existence.

I gladly award her the most honourable of eulogies, that due to the industrious; and I also compliment her on her talent for closing the honey-pots. The pieces stacked into lids are round and have nothing to suggest those of which the cells and the final barricade are made. Excepting the first, those nearest the honey, they are perhaps cut a little less neatly than the disks of the White-girdled Leaf-cutter; no matter: they stop the jar perfectly, especially when there are some ten of them one above the other. When cutting them, the Bee was as sure of her scissors as a dressmaker guided by a pattern laid on the stuff; and yet she was cutting without a model, without having in front of her the mouth to be closed. To enlarge on this interesting subject would mean to repeat oneself. All the Leaf-cutters have the same talent for making the lids of their pots.

A less mysterious question than this geometrical problem is that of the materials. Does each species of Megachile keep to a single plant, or has it a definite botanical domain wherein to exercise its liberty of choice? The little that I have already said is enough to make us suspect that the insect is not restricted to one plant; and this is confirmed by an examination of the separate cells, piece by piece, when we find a variety which we were far from imagining at first. Here is the flora of the Megachiles in my neighbourhood, a very incomplete flora and doubtless capable of considerable amplification by future researches.

The Silky Leaf-cutter gathers the materials for her pots, her lids and her barricades from the following plants: paliurus, hawthorn, vine, wild briar, bramble, holm-oak, amelanchier, terebinthus, sage-leaved rock-rose. The first three supply the greater part of the leaf-work; the last three are represented only by rare fragments.

The Hare-footed Leaf-cutter (Megachile lagopoda, LIN.) which I see very busy in my enclosure, though she only collects her materials there, exploits the lilac and the rose-tree by preference. From time to time, I see her also cutting bits out of the robinia, the quince-tree and the cherry-tree. In the open country, I have found her building with the leaves of the vine alone.

The Silvery Leaf-cutter (Megachile argentata, FAB.), another of my guests, shares the taste of the aforesaid for the lilac and the rose, but her domain includes in addition the pomegranate-tree, the bramble, the vine, the common dogwood and the cornelian cherry.

The White-girdled Leaf-cutter likes the robinia, to which she adds, in lavish proportions, the vine, the rose and the hawthorn and sometimes, in moderation, the reed and the whitish-leaved rock-rose.

The Black-tipped Leaf-cutter (Megachile apicalis, SPIN.) has for her abode the cells of the Mason-bee of the Pebbles and the ruined nests of the Osmiae and Anthidia in the Snail-shells. I have not known her to use any other materials than the wild briar and the hawthorn.

Incomplete though it be, this list tells us that the Megachiles do not have exclusive botanical tastes. Each species manages extremely well with several plants differing greatly in appearance. The first condition to be fulfilled by the shrub exploited is that it be near the nest. Frugal of her time, the Leaf-cutter declines to go on distant expeditions. Whenever I come upon a recent Megachile-nest, I am not long in finding in the neighbourhood, without much searching, the tree or shrub from which the Bee has cut her pieces.

Another main condition is a fine and supple texture, especially for the first disks used in the lid and for the pieces which form the lining of the wallet. The rest, less carefully executed, allows of coarser stuff; but even then the piece must be flexible and lend itself to the cylindrical configuration of the tunnel. The leaves of the rock-roses, thick and roughly fluted, fulfil this condition unsatisfactorily, for which reason I see them occurring only at very rare intervals. The insect has gathered pieces of them by mistake and, not finding them good to use, has ceased to visit the unprofitable shrub. Stiffer still, the leaf of the holm-oak in its full maturity is never employed: the Silky Leaf-cutter uses it only in the young state and then in moderation; she can get her velvety pieces better from the vine. In the lilac-bushes so zealously exploited before my eyes by the Hare-footed Leaf-cutter occur a medley of different shrubs which, from their size and the lustre of their leaves, should apparently suit that sturdy pinker. They are the shrubby hare's-ear, the honeysuckle, the prickly butcher's-broom, the box. What magnificent disks ought to come from the hare's-ear and the honeysuckle! One could get an excellent piece, without further labour, by merely cutting the leaf-stalk of the box, as Megachile sericans does with her paliurus. The lilac-lover disdains them absolutely. For what reason? I fancy that she finds them too stiff. Would she think differently if the lilac-bush were not there? Perhaps so.

In short, apart from the questions of texture and proximity to the nest, the Megachile's choice, it seems to me, must depend upon whether a particular shrub is plentiful or not. This would explain the lavish use of the vine, an object of widespread cultivation, and of the hawthorn and the wild briar, which form part of all our hedges. As these are to be found everywhere, the fact that the different Leaf-cutters make use of them is no reflection upon a host of equivalents varying according to the locality.

If we had to believe what people tell us about the effects of heredity, which is said to hand down from generation to generation, ever more firmly established, the individual habits of those who come before, the Megachiles of these parts, experienced in the local flora by the long training of the centuries, but complete novices in the presence of plants which their race encounters for the first time, ought to refuse as unusual and suspicious any exotic leaves, especially when they have at hand plenty of the leaves made familiar by hereditary custom. The question was deserving of separate study.

Two subjects of my observations, the Hare-footed and the Silvery Leaf-cutter, both of them inmates of my open-air laboratory, gave me a definite answer. Knowing the points frequented by the two Megachiles, I planted in their work-yard, overgrown with briar and lilac, two outlandish plants which seemed to me to fulfil the required conditions of suppleness of texture, namely, the ailantus, a native of Japan, and the Virginian physostegia. Events justified the selection: both Bees exploited the foreign flora with the same assiduity as the local flora, passing from the lilac to the ailantus, from the briar to the physostegia, leaving the one, going back to the other, without drawing distinctions between the known and the unknown. Inveterate habit could not have given greater certainty, greater ease to their scissors, though this was their first experience of such a material.

The Silvery Leaf-cutter lent herself to an even more conclusive test. As she readily makes her nest in the reeds of my apparatus, I was able, up to a certain point, to create a landscape for her and select its vegetation myself. I therefore moved the reed-hive to a part of the enclosure stocked chiefly with rosemary, whose scanty foliage is not adapted for the Bee's work, and near the apparatus I arranged an exotic shrubbery in pots, including notably the smooth lopezia, from Mexico, and the long-fruited capsicum, an Indian annual. Finding close at hand the wherewithal to build her nest, the Leaf-cutter went no further afield. The lopezia suited her especially, so much so that almost the whole nest was composed of it. The rest had been gathered from the capsicum.

Another recruit, whose co-operation I had in no way engineered, came spontaneously to offer me her evidence. This was the Feeble Leaf-cutter (Megachile imbecilla, GERST.). Nearly a quarter of a century ago, I saw her, all through the month of July, cutting out her rounds and ellipses at the expense of the petals of the Pelargonium zonale, the common geranium. Her perseverance devastated—there is no other word for it—my modest array of pots. Hardly was a blossom out, when the ardent Megachiles came and scalloped it into crescents. The colour was indifferent to her: red, white or pink, all the petals underwent the disastrous operation. A few captures, ancient relics of my collecting-boxes by this time, indemnified me for the pillage. I have not seen this unpleasant Bee since. With what does she build when there are no geranium-flowers handy? I do not know; but the fact remains that the fragile tailoress used to attack the foreign flower, a fairly recent acquisition from the Cape, as though all her race had never done anything else.

These details leave us with one obvious conclusion, which is contrary to our original ideas, based on the unvarying character of insect industry. In constructing their jars, the Leaf-cutters, each following the taste peculiar to her species, do not make use of this or that plant to the exclusion of the others; they have no definite flora, no domain faithfully transmitted by heredity. Their pieces of leaves vary according to the surrounding vegetation; they vary in different layers of the same cell. Everything suits them, exotic or native, rare or common, provided that the bit cut out be easy to employ. It is not the general aspect of the shrub, with its fragile or bushy branches, its large or small, green or grey, dull or glossy leaves, that guides the insect: such advanced botanical knowledge does not enter into the question at all. In the thicket chosen as a pinking-establishment, the Megachile sees but one thing: leaves useful for her work. The Shrike, with his passion for plants with long, woolly sprigs, knows where to find nicely-wadded substitutes when his favourite growth, the cotton-rose, is lacking; the Megachile has much wider resources: indifferent to the plant itself, she looks only into the foliage. If she finds leaves of the proper size, of a dry texture capable of defying the damp and of a suppleness favourable to cylindrical curving, that is all she asks; and the rest does not matter. She has therefore an almost unlimited field for her labour.

These sudden and wholly unprovoked changes give cause for reflection. When my geranium-flowers were devastated, how had the obtrusive Bee, untroubled by the profound dissimilarity between the petals, snow-white here, bright scarlet there, how had she learnt her trade? Nothing tells us that she herself was not for the first time exploiting the plant from the Cape; and, if she really did have predecessors, the habit had not had time to become inveterate, considering the modern importation of the geranium. Where again did the Silvery Megachile, for whom I created an exotic shrubbery, make the acquaintance of the lopezia, which comes from Mexico? She certainly is making a first start. Never did her village or mine possess a stalk of that chilly denizen of our hot-houses. She is making a first start; and behold her straightway a graduate, versed in the art of carving unfamiliar foliage.

People often talk of the long apprenticeships served by instinct, of its gradual acquirements, of its talents, the laborious work of the ages. The Megachiles affirm the exact opposite. They tell me that the animal, though invariable in the essence of its art, is capable of innovation in the details; but at the same time they assure me that any such innovation is sudden and not gradual. Nothing prepares the innovations, nothing improves them or hands them down; otherwise a selection would long ago have been made amid the diversity of foliage; and the shrub recognized as the most serviceable, especially when it is also plentiful, would alone supply all the building-materials needed. If heredity transmitted industrial discoveries, a Megachile who thought of cutting her disks out of pomegranate-leaves and found them satisfactory ought to have instilled a liking for similar materials into her descendants; and we should this day find Leaf-cutters faithful to the pomegranate-leaves, workers who remained exclusive in their choice of the raw material. The facts refute these theories.

People also say:

'Grant us a variation, however small, in the insect's industry; and that variation, accentuated more and more, will produce a new race and finally a fixed species.'

This trifling variation is the fulcrum for which Archimedes clamoured in order to lift the world with his system of levers. The Megachiles offer us one and a very great one: the indefinite variation of their materials. What will the theorists' levers lift with this fulcrum? Why, nothing at all! Whether they cut the delicate petals of the geranium or the tough leaves of the lilac-bushes, the Leaf-cutters are and will be what they were. This is what we learn from the persistence of each species in its structural details, despite the great variety of the foliage employed.



CHAPTER 9. THE COTTON-BEES.

The evidence of the Leaf-cutters proves that a certain latitude is left to the insect in its choice of materials for the nest; and this is confirmed by the testimony of the Anthidia, the cotton-manufacturers. My district possesses five: A. Florentinum, LATR., A. diadema, LATR., A. manicatum, LATR., A. cingulatum, LATR., A. scapulare, LATR. None of them creates the refuge in which the cotton goods are manufactured. Like the Osmiae and the Leaf-cutters, they are homeless vagrants, adopting, each to her own taste, such shelter as the work of others affords. The Scapular Anthidium is loyal to the dry bramble, deprived of its pith and turned into a hollow tube by the industry of various mining Bees, among which figure, in the front rank, the Ceratinae, dwarf rivals of the Xylocopa, or Carpenter-bee, that mighty driller of rotten wood. The spacious galleries of the Masked Anthophora suit the Florentine Anthidium, the foremost member of the genus so far as size is concerned. The Diadem Anthidium considers that she has done very well if she inherits the vestibule of the Hairy-footed Anthophora, or even the ordinary burrow of the Earth-worm. Failing anything better, she may establish herself in the dilapidated dome of the Mason-bee of the Pebbles. The Manicate Anthidium shares her tastes. I have surprised the Girdled Anthidium cohabiting with a Bembex-wasp. The two occupants of the cave dug in the sand, the owner and the stranger, were living in peace, both intent upon their business. Her usual habitation is some hole or other in the crevices of a ruined wall. To these refuges, the work of others, we can add the stumps of reeds, which are as popular with the various cotton-gatherers as with the Osmiae; and, after we have mentioned a few most unexpected retreats, such as the sheath provided by a hollow brick or the labyrinth furnished by the lock of a gate, we shall have almost exhausted the list of domiciles.

Like the Osmiae and the Leaf-cutters, the Anthidium shows an urgent need of a ready-made home. She never houses herself at her own expense. Can we discover the reason? Let us first consult a few hard workers who are artificers of their own dwellings. The Anthophora digs corridors and cells in the road-side banks hardened by the sun; she does not erect, she excavates; she does not build, she clears. Toiling away with her mandibles, atom by atom, she manages to contrive the passages and chambers necessary for her eggs; and a huge business it is. She has, in addition, to polish and glaze the rough sides of her tunnels. What would happen if, after obtaining a home by dint of long-continued toil, she had next to line it with wadding, to gather the fibrous down from cottony plants and to felt it into bags suitable for the honey-paste? The hard-working Bee would not be equal to producing all these refinements. Her mining calls for too great an expenditure of time and strength to leave her the leisure for luxurious furnishing. Chambers and corridors, therefore, will remain bare.

The Carpenter-bee gives us the same answer. When with her joiner's wimble she has patiently bored the beam to a depth of nine inches, would she be able to cut out and place in position the thousand and one pieces which the Silky Leaf-cutter employs for her nest? Time would fail her, even as it would fail a Megachile who, lacking the Capricorn's chamber, had herself to dig a home in the trunk of the oak. Therefore the Carpenter-bee, after the tedious work of boring, gets the installation done in the most summary fashion, simply running up a sawdust partition.

The two things, the laborious business of obtaining a lodging and the artistic work of furnishing, seem unable to go together. With the insect as with man, he who builds the house does not furnish it, he who furnishes it does not build it. To each his share, because of lack of time. Division of labour, the mother of the arts, makes the workman excel in his department; one man for the whole work would mean stagnation, the worker never getting beyond his first crude attempts. Animal industry is a little like our own: it does not attain its perfection save with the aid of obscure toilers, who, without knowing it, prepare the final masterpiece. I see no other reason for this need of a gratuitous lodging for the Megachile's leafy basket or the Anthidia's cotton purses. In the case of other artists who handle delicate things that require protection, I do not hesitate to assume the existence of a ready-made home. Thus Reaumur tells us of the Upholsterer-bee, Anthocopa papaveris, who fashions her cells with poppy-petals. I do not know the flower-cutter, I have never seen her; but her art tells me plainly enough that she must establish herself in some gallery wrought by others, as, for instance, in an Earth-worm's burrow.

We have but to see the nest of a Cotton-bee to convince ourselves that its builder cannot at the same time be an indefatigable navvy. When and newly-felted and not yet made sticky with honey, the wadded purse is by far the most elegant known specimen of entomological nest-building, especially where the cotton is of a brilliant white, as is frequently the case in the manufacturers of the Girdled Anthidium. No bird's-nest, however deserving of our admiration, can vie in fineness of flock, in gracefulness of form, in delicacy of felting with this wonderful bag, which our fingers, even with the aid of tools, could hardly imitate, for all their dexterity. I abandon the attempt to understand how, with its little bales of cotton brought up one by one, the insect, no otherwise gifted than the kneaders of mud and the makers of leafy baskets, manages to felt what it has collected into a homogeneous whole and then to work the product into a thimble-shaped wallet. Its tools as a master-fuller are its legs and its mandibles, which are just like those possessed by the mortar-kneaders and Leaf-cutters; and yet, despite this similarity of outfit, what a vast difference in the results obtained!

To see the Cotton-bees' talents in action seems an undertaking fraught with innumerable difficulties: things happen at a depth inaccessible to the eye; and to persuade the insect to work in the open does not lie in our power. One resource remained and I did not fail to turn to it, though hitherto I have been wholly unsuccessful. Three species, Anthidium diadema, A. manicatum and A. florentinum—the first-named in particular—show themselves quite ready to take up their abode in my reed-apparatus. All that I had to do was to replace the reeds by glass tubes, which would allow me to watch the work without disturbing the insect. This stratagem had answered perfectly with the Three-horned Osmia and Latreille's Osmia, whose little housekeeping-secrets I had learnt thanks to the transparent dwelling-house. Why should it not answer for its Cotton-bees and, in the same way, with the Leaf-cutters? I almost counted on success. Events betrayed my confidence. For four years I supplied my hives with glass tubes and not once did the Cotton-weavers or the Leaf-cutters condescend to take up their quarters in the crystal palaces. They always preferred the hovel provided by the reed. Shall I persuade them one day? I do not abandon all hope.

Meanwhile, let me describe the little that I saw. More or less stocked with cells, the reed is at last closed, right at the orifice, with a thick plug of cotton, usually coarser than the wadding of the honey-satchels. It is the equivalent of the Three-horned Osmia's barricade of mud, of the leaf-putty of Latreille's Osmia, of the Megachiles' barrier of leaves cut into disks. All these free tenants are careful to shut tight the door of the dwelling, of which they have often utilized only a portion. To watch the building of this barricade, which is almost external work, demands but a little patience in waiting for the favourable moment.

The Anthidium arrives at last, carrying the bale of cotton for the plugging. With her fore-legs she tears it apart and spreads it out; with her mandibles, which go in closed and come out open, she loosens the hard lumps of flock; with her forehead she presses each new layer upon the one below. And that is all. The insect flies off, returns the richer by another bale and repeats the performance until the cotton barrier reaches the level of the opening. We have here, remember, a rough task, in no way to be compared with the delicate manufacturer of the bags; nevertheless, it may perhaps tell us something of the general procedure of the finer work. The legs do the carding, the mandibles the dividing, the forehead the pressing; and the play of these implements produces the wonderful cushioned wallet. That is the mechanism in the lump; but what of the artistry?

Let us leave the unknown for facts within the scope of observation. I will question the Diadem Anthidium in particular, a frequent inmate of my reeds. I open a reed-stump about two decimetres long by twelve millimetres in diameter. (About seven and three-quarter inches by half an inch.—Translator's Note.) The end is occupied by a column of cotton-wool comprising ten cells, without any demarcation between them on the outside, so that their whole forms a continuous cylinder. Moreover, thanks to a close felting, the different compartments are soldered together, so much so that, when pulled by the end, the cotton edifice does not break into sections, but comes out all in one piece. One would take it for a single cylinder, whereas in reality the work is composed of a series of chambers, each of which has been constructed separately, independently of the one before, except perhaps at the base.

For this reason, short of ripping up the soft dwelling, still full of honey, it is impossible to ascertain the number of storeys; we must wait until the cocoons are woven. Then our fingers can tell the cells by counting the knots that resist pressure under the cover of wadding. This general structure is easily explained. A cotton bag is made, with the sheath of the reed as a mould. If this guiding sheath were lacking, the thimble shape would be obtained all the same, with no less elegance, as is proved by the Girdled Anthidium, who makes her nest in some hiding-place or other in the walls or the ground. When the purse is finished, the provisions come and the egg, followed by the closing of the cell. We do not here find the geometrical lid of the Leaf-cutters, the pile of disks tight-set in the mouth of the jar. The bag is closed with a cotton sheet whose edges are soldered by a felting-process to the edges of the opening. The soldering is so well done that the honey-pouch and its cover form an indivisible whole. Immediately above it, the second cell is constructed, having its own base. At the beginning of this work, the insect takes care to join the two storeys by felting the ceiling of the first to the floor of the second. Thus continued to the end, the work, with its inner solderings, becomes an unbroken cylinder, in which the beauties of the separate wallets disappear from view. In very much the same fashion, but with less adhesion among the different cells, do the Leaf-cutters act when stacking their jars in a column without any external division into storeys.

Let us return to the reed-stump which gives us these details. Beyond the cotton-wool cylinder wherein ten cocoons are lodged in a row comes an empty space of half a decimetre or more. (About two inches.—Translator's Note.) The Osmiae and the Leaf-cutters are also accustomed to leave these long, deserted vestibules. The nest ends, at the orifice of the reed, with a strong plug of flock coarser and less white than that of the cells. This use of closing-materials which are less delicate in texture but of greater resisting-power, while not an invariable characteristic, occurs frequently enough to make us suspect that the insect knows how to distinguish what is best suited now to the snug sleeping-berth of the larvae, anon to the defensive barricade of the home. Sometimes the choice is an exceedingly judicious one, as is shown by the nest of the Diadem Anthidium. Time after time, whereas the cells were composed of the finest grade of white cotton, gathered from Centaurea solsticialis, or St. Barnaby's thistle, the barrier at the entrance, differing from the rest of the work in its yellow colouring, was a heap of close-set bristles supplied by the scallop-leaved mullein. The two functions of the wadding are here plainly marked. The delicate skin of the larvae needs a well-padded cradle; and the mother collects the softest materials that the cottony plants provide. Rivalling the bird, which furnishes the inside of the nest with wool and strengthens the outside with sticks, she reserves for the grubs' mattress the finest down, so hard to find and collected with such patience. But, when it becomes a matter of shutting the door against the foe, then the entrance bristles with forbidding caltrops, with stiff, prickly hairs.

This ingenious system of defence is not the only one known to the Anthidia. More distrustful still, the Manicate Anthidium leaves no space in the front part of the reed. Immediately after the column of cells, she heaps up, in the uninhabited vestibule, a conglomeration of rubbish, whatever chance may offer in the neighbourhood of the nest: little pieces of gravel, bits of earth, grains of sawdust, particles of mortar, cypress-catkins, broken leaves, dry Snail-droppings and any other material that comes her way. The pile, a real barricade this time, blocks the reed completely to the end, except about two centimetres (About three-quarters of an inch.—Translator's Note.) left for the final cotton plug. Certainly no foe will break in through the double rampart; but he will make an insidious attack from the rear. The Leucopsis will come and, with her long probe, thanks to some imperceptible fissure in the tube, will insert her dread eggs and destroy every single inhabitant of the fortress. Thus are the Manicate Anthidium's anxious precautions outwitted.

If we had not already seen the same thing with the Leaf-cutters, this would be the place to enlarge upon the useless tasks undertaken by the insect when, with its ovaries apparently depleted, it goes on spending its strength with no maternal object in view and for the sole pleasure of work. I have come across several reeds stopped up with flock though containing nothing at all, or else furnished with one, two or three cells devoid of provisions or eggs. The ever-imperious instinct for gathering cotton and felting it into purses and heaping it into barricades persists, fruitlessly, until life fails. The Lizard's tail wriggles, curls and uncurls after it is detached from the animal's body. In these reflex movements, I seem to see not an explanation, certainly, but a rough image of the industrious persistency of the insect, still toiling away at its business, even when there is nothing useful left to do. This worker knows no rest but death.

I have said enough about the dwelling of the Diadem Anthidium; let us look at the inhabitant and her provisions. The honey is pale-yellow, homogeneous and of a semifluid consistency, which prevents it from trickling through the porous cotton bag. The egg floats on the surface of the heap, with the end containing the head dipped into the paste. To follow the larva through its progressive stages is not without interest, especially on account of the cocoon, which is one of the most singular that I know. With this object in view, I prepare a few cells that lend themselves to observation. I take a pair of scissors, slice a piece off the side of the cotton-wool purse, so as to lay bare both the victuals and the consumer, and place the ripped cell in a short glass tube. During the first few days, nothing striking happens. The little grub, with its head still plunged in the honey, slakes its thirst with long draughts and waxes fat. A moment comes...But let us go back a little farther, before broaching this question of sanitation.

Every grub, of whatever kind, fed on provisions collected by the mother and placed in a narrow cell is subject to conditions of health unknown to the roving grub that goes where it likes and feeds itself on what it can pick up. The first, the recluse, is no more able than the second, the gadabout, to solve the problem of a food which can be entirely assimilated, without leaving an unclean residue. The second gives no thought to these sordid matters: any place suits it for getting rid of that difficulty. But what will the other do with its waste matter, cooped up as it is in a tiny cell stuffed full of provisions? A most unpleasant mixture seems inevitable. Picture the honey-eating grub floating on liquid provisions and fouling them at intervals with its excretions! The least movement of the hinder-part would cause the whole to amalgamate; and what a broth that would make for the delicate nursling! No, it cannot be; those dainty epicures must have some method of escaping these horrors.

They all have, in fact, and most original methods at that. Some take the bull by the horns, so to speak, and, in order not to soil things, refrain from uncleanliness until the end of the meal: they keep the dropping-trap closed as long as the victuals are unfinished. This is a radical scheme, but not in every one's power, it appears. It is the course adopted, for instance, by the Sphex-wasps and the Anthophora-bees, who, when the whole of the food is consumed, expel at one shot the residues amassed in the intestines since the commencement of the repast.

Others, the Osmiae in particular, accept a compromise and begin to relieve the digestive tract when a suitable space has been made in the cell through the gradual disappearance of the victuals. Others again—more hurried these—find means of obeying the common law pretty early by engaging in stercoral manufactures. By a stroke of genius, they make the unpleasant obstruction into building-bricks. We already know the art of the Lily-beetle (Crioceris merdigera. Fabre's essay on this insect has not yet been translated into English; but readers interested in the matter will find a full description in "An Introduction to Entomology," by William Kirby, Rector of Barham, and William Spence: letter 21.—Translator's Note.), who, with her soft excrement, makes herself a coat wherein to keep cool in spite of the sun. It is a very crude and revolting art, disgusting to the eye. The Diadem Anthidium belongs to another school. With her droppings she fashions masterpieces of marquetry and mosaic, which wholly conceal their base origin from the onlooker. Let us watch her labours through the windows of my tubes.

When the portion of food is nearly half consumed, there begins and goes on to the end a frequent defecation of yellowish droppings, each hardly the size of a pin's head. As these are ejected, the grub pushes them back to the circumference of the cell with a movement of its hinder-part and keeps them there by means of a few threads of silk. The work of the spinnerets, therefore, which is deferred in the others until the provisions are finished, starts earlier here and alternates with the feeding. In this way, the excretions are kept at a distance, away from the honey and without any danger of getting mixed with it. They end by becoming so numerous as to form an almost continuous screen around the larva. This excremental awning, made half of silk and half of droppings, is the rough draft of the cocoon, or rather a sort of scaffolding on which the stones are deposited until they are definitely placed in position. Pending the piecing together of the mosaic, the scaffolding keeps the victuals free from all contamination.

To get rid of what cannot be flung outside, by hanging it on the ceiling, is not bad to begin with; but to use it for making a work of art is better still. The honey has disappeared. Now commences the final weaving of the cocoon. The grub surrounds itself with a wall of silk, first pure white, then tinted reddish-brown by means of an adhesive varnish. Through its loose-meshed stuff, it seizes one by one the droppings hanging from the scaffold and inlays them firmly in the tissue. The same mode of work is employed by the Bembex-, Stizus-and Tachytes-wasps and other inlayers, who strengthen the inadequate woof of their cocoons with grains of sand; only, in their cotton-wool purses, the Anthidium's grubs substitute for the mineral particles the only solid materials at their disposal. For them, excrement takes the place of pebbles.

And the work goes none the worse for it. On the contrary: when the cocoon is finished, any one who had not witnessed the process of manufacture would be greatly puzzled to state the nature of the workmanship. The colouring and the elegant regularity of the outer wrapper of the cocoon suggest some kind of basket-work made with tiny bits of bamboo, or a marquetry of exotic granules. I too let myself be caught by it in my early days and wondered in vain what the hermit of the cotton wallet had used to inlay her nymphal dwelling so prettily withal. To-day, when the secret is known to me, I admire the ingenuity of the insect capable of obtaining the useful and the beautiful out of the basest materials.

The cocoon has another surprise in store for us. The end containing the head finishes with a short conical nipple, an apex, pierced by a narrow shaft that establishes a communication between the inside and the out. This architectural feature is common to all the Anthidia, to the resin-workers who will occupy our attention presently, as well as to the cotton-workers. It is found nowhere outside the Anthidium group.

What is the use of this point which the larva leaves bare instead of inlaying it like the rest of the shell? What is the use of that hole, left quite open or, at most, closed at the bottom with a feeble grating of silk? The insect appears to attach great importance to it, from what I see. In point of fact, I watch the careful work of the apex. The grub, whose movements the hole enables me to follow, patiently perfects the lower end of the conical channel, polishes it and gives it an exactly circular shape; from time to time, it inserts into the passage its two closed mandibles, whose points project a little way outside; then, opening them to a definite radius, like a pair of compasses, it widens the aperture and makes it regular.

I imagine, without venturing, however, to make a categorical statement, that the perforated apex is a chimney to admit the air required for breathing. Every pupa breathes in its shell, however compact this may be, even as the unhatched bird breathes inside the egg. The thousands of pores with which the shell is pierced allow the inside moisture to evaporate and the outer air to penetrate as and when needed. The stony caskets of the Bembex- and Stizus-wasps are endowed, notwithstanding their hardness, with similar means of exchange between the vitiated and the pure atmosphere. Can the shells of the Anthidia be air-proof, owing to some modification that escapes me? In any case, this impermeability cannot be attributed to the excremental mosaic, which the cocoons of the resin-working Anthidia do not possess, though endowed with an apex of the very best.

Shall we find an answer to the question in the varnish with which the silken fabric is impregnated? I hesitate to say yes and I hesitate to say no, for a host of cocoons are coated with a similar lacquer though deprived of communication with the outside air. All said, without being able at present to account for its necessity, I admit that the apex of the Anthidia is a breathing-aperture. I bequeath to the future the task of telling us for what reasons the collectors of both cotton and resin leave a large pore in their shells, whereas all the other weavers close theirs completely.

After these biological curiosities, it remains for me to discuss the principal subject of this chapter: the botanical origin of the materials of the nest. By watching the insect when busy at its harvesting, or else by examining its manufactured flock under the microscope, I was able to learn, not without a great expenditure of time and patience, that the different Anthidia of my neighbourhood have recourse without distinction to any cottony plant. Most of the wadding is supplied by the Compositae, particularly the following: Centaurea solsticialis, or St. Barnaby's thistle; C. paniculata, or panicled centaury; Echinops ritro, or small globe-thistle; Onopordon illyricum, or Illyrian cotton-thistle; Helichrysum staechas, or wild everlasting; Filago germanica, or common cotton-rose. Next come the Labiatae: Marrubium vulgare, or common white horehound; Ballota fetida, or stinking horehound; Calamintha nepeta, or lesser calamint; Salvia aethiopis, or woolly sage. Lastly, the Solanaceae: Verbascum thapsus, or shepherd's club; V. sinuatum, or scollop-leaved mullein.

The Cotton-bees' flora, we see, incomplete as it is in my notes, embraces plants of very different aspect. There is no resemblance in appearance between the proud candelabrum of the cotton-thistle, with its red tufts, and the humble stalk of the globe-thistle, with its sky-blue capitula; between the plentiful leaves of the mullein and the scanty foliage of the St. Barnaby's thistle; between the rich silvery fleece of the woolly sage and the short hairs of the everlasting. With the Anthidium, these clumsy botanical characteristics do not count; one thing alone guides her: the presence of cotton. Provided that the plant be more or less well-covered with soft wadding, the rest is immaterial to her.

Another condition, however, has to be fulfilled, apart from the fineness of the cotton-wool. The plant, to be worth shearing, must be dead and dry. I have never seen the harvesting done on fresh plants. In this way, the Bee avoids mildew, which would make its appearance in a mass of hairs still filled with sap.

Faithful to the plant recognized as yielding good results, the Anthidium arrives and resumes her gleaning on the edges of the parts denuded by earlier harvests. Her mandibles scrape away and pass the tiny fluffs, one by one, to the hind-legs, which hold the pellet pressed against the chest, mix with it the rapidly-increasing store of down and make the whole into a little ball. When this is the size of a pea, it goes back into the mandibles; and the insect flies off, with its bale of cotton in its mouth. If we have the patience to wait, we shall see it return to the same point, at intervals of a few minutes, so long as the bag is not made. The foraging for provisions will suspend the collecting of cotton; then, next day or the day after, the scraping will be resumed on the same stalk, on the same leaf, if the fleece be not exhausted. The owner of a rich crop appears to keep to it until the closing-plug calls for coarser materials; and even then this plug is often manufactured with the same fine flock as the cells.

After ascertaining the diversity of cotton-fields among our native plants, I naturally had to enquire whether the Cotton-bee would also put up with exotic plants, unknown to her race; whether the insect would show any hesitation in the presence of woolly plants offered for the first time to the rakes of her mandibles. The common clary and the Babylonian centaury, with which I have stocked the harmas, shall be the harvest-fields; the reaper shall be the Diadem Anthidium, the inmate of my reeds.

The common clary, or toute-bonne, forms part, I know, of our French flora to-day; but it is an acclimatized foreigner. They say that a gallant crusader, returning from Palestine with his share of glory and bruises, brought back the toute-bonne from the Levant to help him cure his rheumatism and dress his wounds. From the lordly manor, the plant propagated itself in all directions, while remaining faithful to the walls under whose shelter the noble dames of yore used to grow it for their unguents. To this day, feudal ruins are its favourite resorts. Crusaders and manors disappeared; the plant remained. In this case, the origin of the clary, whether historical or legendary, is of secondary importance. Even if it were of spontaneous growth in certain parts of France, the toute-bonne is undoubtedly a stranger in the Vaucluse district. Only once in the course of my long botanizing-expeditions across the department have I come upon this plant. It was at Caromb, in some ruins, nearly thirty years ago. I took a cutting of it; and since then the crusaders' sage has accompanied me on all my peregrinations. My present hermitage possesses several tufts of it: but, outside the enclosure, except at the foot of the walls, it would be impossible to find one. We have, therefore, a plant that is new to the country for many miles around, a cotton-field which the Serignan Cotton-bees had never utilized before I came and sowed it.

Nor had they ever made use of the Babylonian centaury, which I was the first to introduce in order to cover my ungrateful stony soil with some little vegetation. They had never seen anything like the colossal centaury imported from the region of the Euphrates. Nothing in the local flora, not even the cotton-thistle, had prepared them for this stalk as thick as a child's wrist, crowned at a height of nine feet with a multitude of yellow balls, nor for those great leaves spreading over the ground in an enormous rosette. What will they do in the presence of such a find? They will take possession of it with no more hesitation than if it were the humble St. Barnaby's thistle, the usual purveyor.

In fact, I place a few stalks of clary and Babylonian centaury, duly dried, near the reed-hives. The Diadem Anthidium is not long in discovering the rich harvest. Straight away the wool is recognized as being of excellent quality, so much so that, during the three or four weeks of nest-building, I can daily witness the gleaning, now on the clary, now on the centaury. Nevertheless the Babylonian plant appears to be preferred, no doubt because of its whiter, finer and more plentiful down. I keep a watchful eye on the scraping of the mandibles and the work of the legs as they prepare the pellet; and I see nothing that differs from the operations of the insect when gleaning on the globe-thistle and the St. Barnaby's thistle. The plant from the Euphrates and the plant from Palestine are treated like those of the district.

Thus we find what the Leaf-cutters taught us proved, in another way, by the cotton-gatherers. In the local flora, the insect has no precise domain; it reaps its harvest readily now from one species, now from another, provided that it find the materials for its manufactures. The exotic plant is accepted quite as easily as that of indigenous growth. Lastly, the change from one plant to another, from the common to the rare, from the habitual to the exceptional, from the known to the unknown, is made suddenly, without gradual initiations. There is no novitiate, no training by habit in the choice of the materials for the nest. The insect's industry, variable in its details by sudden, individual and non-transmissible innovations, gives the lie to the two great factors of evolution: time and heredity.



CHAPTER 10. THE RESIN-BEES.

At the time when Fabricius (Johann Christian Fabricius (1745-1808), a noted Danish entomologist, author of "Systema entomologiae" (1775).—Translator's Note.) gave the genus Anthidium its name, a name still used in our classifications, entomologists troubled very little about the live animal; they worked on corpses, a dissecting-room method which does not yet seem to be drawing to an end. They would examine with a conscientious eye the antenna, the mandible, the wing, the leg, without asking themselves what use the insect had made of those organs in the exercise of its calling. The animal was classified very nearly after the manner adopted in crystallography. Structure was everything; life, with its highest prerogatives, intellect, instinct, did not count, was not worthy of admission into the zoological scheme.

It is true that an almost exclusively necrological study is obligatory at first. To fill one's boxes with insects stuck on pins is an operation within the reach of all; to watch those same insects in their mode of life, their work, their habits and customs is quite a different thing. The nomenclator who lacks the time—and sometimes also the inclination—takes his magnifying-glass, analyzes the dead body and names the worker without knowing its work. Hence the number of appellations the least of whose faults is that they are unpleasant to the ear, certain of them, indeed, being gross misnomers. Have we not, for instance, seen the name of Lithurgus, or stone-worker, given to a Bee who works in wood and nothing but wood? Such absurdities will be inevitable until the animal's profession is sufficiently familiar to lend its aid in the compiling of diagnoses. I trust that the future will see this magnificent advance in entomological science: men will reflect that the impaled specimens in our collections once lived and followed a trade; and anatomy will be kept in its proper place and made to leave due room for biology.

Fabricius did not commit himself with his expression Anthidium, which alludes to the love of flowers, but neither did he mention anything characteristic: as all Bees have the same passion in a very high degree, I see no reason to treat the Anthidia as more zealous looters than the others. If he had known their cotton nests, perhaps the Scandinavian naturalist would have given them a more logical denomination. As for me, in a language wherein technical parade is out of place, I will call them the Cotton-bees.

The term requires some limiting. To judge by my finds, in fact, the old genus Anthidium, that of the classifying entomologists, comprises in my district two very different corporations. One is known to us and works exclusively in wadding; the other, which we are about to study, works in resin, without ever having recourse to cotton. Faithful to my extremely simple principle of defining the worker, as far as possible, by his work, I will call the members of this guild the Resin-bees. Thus confining myself to the data supplied by my observations, I divide the Anthidium group into equal sections, of equal importance, for which I demand special generic titles; for it is highly illogical to call the carders of wool and the kneaders of resin by the same name. I surrender to those whom it concerns the honour of effecting this reform in the orthodox fashion.

Good luck, the friend of the persevering, made me acquainted in different parts of Vaucluse with four Resin-bees whose singular trade no one had yet suspected. To-day, I find them all four again in my own neighbourhood. They are the following: Anthidium septemdentatum, LATR., A. bellicosum, LEP., A. quadrilobum, LEP., and A. Latreillii, LEP. The first two make their nests in deserted Snail-shells; the other two shelter their groups of cells sometimes in the ground, sometimes under a large stone. We will first discuss the inhabitants of the Snail-shell. I made a brief reference to them in an earlier chapter, when speaking of the distribution of the sexes. This mere allusion, suggested by a study of a different kind, must now be amplified. I return to it with fuller particulars.

The stone-heaps in the Roman quarries near Serignan, which I have so often visited in search of the nests of the Osmia who takes up her abode in Snail-shells, supply me also with the two Resin-bees installed in similar quarters. When the Field-mouse has left behind him a rich collection of empty shells scattered all round his hay mattress under the slab, there is always a hope of finding some Snail-shells plugged with mud and, here and there, mixed with them, a few Snail-shells closed with resin. The two Bees work next door to each other, one using clay, the other gum. The excellence of the locality is responsible for this frequent cohabitation, shelter being provided by the broken stone from the quarry and lodgings by the shells which the Mouse has left behind.

At places where dead Snail-shells are few and far between, as in the crevices of rustic walls, each Bee occupies by herself the shells which she has found. But here, in the quarries, our crop will certainly be a double or even a treble one, for both Resin-bees frequent the same heaps. Let us, therefore, lift the stones and dig into the mound until the excessive dampness of the subsoil tells us that it is useless to look lower down. Sometimes at the moment of removing the first layer, sometimes at a depth of eighteen inches, we shall find the Osmia's Snail-shell and, much more rarely, the Resin-bee's. Above all, patience! The job is none of the most fruitful; nor is it exactly an agreeable one. By dint of turning over uncommonly jagged stones, our fingertips get hurt, lose their skin and become as smooth as though we had held them on a grindstone. After a whole afternoon of this work, our back will be aching, our fingers will be itching and smarting and we shall possess a dozen Osmia-nests and perhaps two or three Resin-bees' nests. Let us be content with that.

The Osmia's shells can be recognized at once, as being closed at the orifice with a clay cover. The Anthidium's call for a special examination, without which we should run a great risk of filling our pockets with cumbersome rubbish. We find a dead Snail-shell among the stones. Is it inhabited by the Resin-bee or not? The outside tells us nothing. The Anthidium's work comes at the bottom of the spiral, a long way from the mouth; and, though this is wide open, the eye cannot travel far enough along the winding stair. I hold up the doubtful shell to the light. If it is completely transparent, I know that it is empty and I put it back to serve for future nests. If the second whorl is opaque, the spiral contains something. What does it contain? Earth washed in by the rain? Remnants of the putrefied Snail? That remains to be seen. With a little pocket-trowel, the inquisitorial implement which always accompanies me, I make a wide window in the middle of the final whorl. If I see a gleaming resin floor, with incrustations of gravel, the thing is settled: I possess an Anthidium's nest. But, oh the number of failures that go to one success! The number of windows vainly opened in shells whose bottom is stuffed with clay or with noisome corpses! Thus picking shells among the overturned stone-heaps, inspecting them in the sun, breaking into them with the trowel and nearly always rejecting them, I manage, after repeated attempts, to obtain my materials for this chapter.

The first to hatch is the Seven-pronged Resin-bee (Anthidium septemdentatum). We see her, in the month of April, lumbering along to the rubbish-heaps in the quarries and the low boundary-walls, in search of her Snail-shell. She is a contemporary of the Three-horned Osmia, who begins operations in the last week of April, and often occupies the same stone-heap, settling in the next shell. She is well-advised to start work early and to be on neighbourly terms with the Osmia when the latter is building; in fact, we shall soon see the terrible dangers to which that same proximity exposes her dilatory rival in resin-work, Anthidium bellicosum.

The shell adopted in the great majority of cases is that of the Common Snail, Helix aspersa. It is sometimes of full size, sometimes half-developed. Helix nemoralis and H. caespitum, which are much smaller, also supply suitable lodgings; and this would as surely apply to any shell of sufficient capacity, if the places which I explore possessed others, as witness a nest which my son Emile has sent me from somewhere near Marseilles. This time, the Resin-bee is settled in Helix algira, the most remarkable of our land-shells because of the width and regularity of its spiral, which is copied from that of the Ammonites. This magnificent nest, a perfect specimen of both the Snail's work and the Bee's, deserves description before any other.

For a distance of three centimetres (1.17 inches.—Translator's Note.) from the mouth, the last spiral whorl contains nothing. At this inconsiderable depth, a partition is clearly seen. The moderate diameter of the passage accounts for the Anthidium's choice of this site to which our eye can penetrate. In the common Snail-shell, whose cavity widens rapidly, the insect establishes itself much farther back, so that, in order to see the terminal partition, we must, as I have said, make a lateral inlet. The position of this boundary-ceiling, which may come farther forward or farther back, depends on the variable diameter of the passage. The cells of the cocoons require a certain length and a certain breadth, which the mother finds by going higher up or lower down in the spiral, according to the shape of the shell. When the diameter is suitable, the last whorl is occupied up to the orifice, where the final lid appears, absolutely exposed to view. This is the case with the adult Helix nemoralis and H. caespitum, and also with the young Common Snail. We will not linger at present over this peculiarity, the importance of which will become manifest shortly.

Whether in the front or at the back of the spiral slope, the insect's work ends in a facade of coarse mosaic, formed of small, angular bits of gravel, firmly cemented with a gum the nature of which has to be ascertained. It is an amber-coloured material, semi-transparent, brittle, soluble in spirits of wine and burning with a sooty flame and a strong smell of resin. From these characteristics it is evident that the Bee prepares her gum with the resinous drops exuded by the Coniferae.

I think that I am even able to name the particular plant, though I have never caught the insect in the act of gathering its materials. Hard by the stone-heaps which I turn over for my collections there is a plentiful supply of brown-berried junipers. Pines are totally absent; and the cypress only appears occasionally near the houses. Moreover, among the vegetable remains which we shall see assisting in the protection of the nest, we often find the juniper's catkins and needles. As the resin-insect is economical of its time and does not fly far from the quarters familiar to it, the gum must have been collected on the shrub at whose foot the materials for the barricade have been gathered. Nor is this merely a local circumstance, for the Marseilles nest abounds in similar remnants. I therefore regard the juniper as the regular resin-purveyor, without, however, excluding the pine, the cypress and other Coniferae when the favourite shrub is absent.

The bits of gravel in the lid are angular and chalky in the Marseilles nest; they are round and flinty in most of the Serignan nests. In making her mosaic, the worker pays no heed to the form or colour of its component parts; she collects indiscriminately anything that is hard enough and not too large. Sometimes she lights upon treasures that give her work a more original character. The Marseilles nest shows me, neatly encrusted amid the bits of gravel, a tiny whole landshell, Pupa cineres. A nest in my own neighbourhood provides me with a pretty Snail-shell, Helix striata, forming a rose-pattern in the middle of the mosaic. These little artistic details remind me of a certain nest of Eumenes Amadei (A Mason-wasp, forming the subject of an essay which has not yet been published in English.—Translator's Note.) which abounds in small shells. Ornamental shell-work appears to number its lovers among the insects.

After the lid of resin and gravel, an entire whorl of the spiral is occupied by a barricade of incongruous remnants, similar to that which, in the reeds, protects the row of cocoons of the Manicate Cotton-bee. It is curious to see exactly the same defensive methods employed by two builders of such different talents, one of whom handles flock, the other gum. The nest from Marseilles has for its barricade bits of chalky gravel, particles of earth, fragments of sticks, a few scraps of moss and especially juniper-catkins and needles. The Serignan nests, installed in Helix aspersa, have almost the same protective materials. I see bits of gravel, the size of a lentil, and the catkins and needles of the brown-berried juniper predominating. Next come the dry excretions of the Snail and a few rare little land-shells. A similar jumble of more or less everything found near the nest forms, as we know, the barricade of the Manicate Cotton-bee, who is also an adept at using the Snail's stercoral droppings after these have been dried in the sun. Let us observe finally that these dissimilar materials are heaped together without any cementing, just as the insect has picked them up. Resin plays no part in the mass; and we have only to pierce the lid and turn the shell upside down for the barricade to come dribbling to the ground. To glue the whole thing together does not enter into the Resin-bee's scheme. Perhaps such an expenditure of gum is beyond her means; perhaps the barricade, if hardened into a solid block, would afterwards form an invincible obstacle to the escape of the youngsters; perhaps again the mass of gravel is an accessory rampart, run up roughly as a work of secondary importance.

Amid these doubtful matters, I see at least that the insect does not look upon its barricade as indispensable. It employs it regularly in the large shells, whose last whorl, too spacious to be used, forms an unoccupied vestibule; it neglects it in the moderate shells, such as Helix nemoralis, in which the resin lid is level with the orifice. My excavations in the stone-heaps supply me with an almost equal number of nests with and without defensive embankments. Among the Cotton-bees, the Manicate Anthidium is not faithful either to her fort of little sticks and stones; I know some of her nests in which cotton serves every purpose. With both of them, the gravel rampart seems useful only in certain circumstances, which I am unable to specify.

On the other side of the outworks of the fortification, the lid and barricade, are the cells set more or less far down in the spiral, according to the diameter of the shell. They are bounded back and front by partitions of pure resin, without any encrustations of mineral particles. Their number is exceedingly restricted and is usually limited to two. The front room, which is larger because the width of the passage goes on increasing, is the abode of a male, superior in size to the other sex; the less spacious back room contains a female. I have already drawn attention in an earlier chapter to the wonderful problem submitted for our consideration by this breaking up of the laying into couples and this alternation of the males and females. Without calling for other work than the transverse partitions, the broadening stairway of the Snail-shell thus furnishes both sexes with house-room suited to their size.

The second Resin-bee that inhabits shells, Anthidium bellicosum, hatches in July and works during the fierce heat of August. Her architecture differs in no wise from that of her kinswoman of the springtime, so much so that, when we find a tenanted Snail-shell in a hole in the wall or under the stones, it is impossible to decide to which of the two species the nest belongs. The only way to obtain exact information is to break the shell and split the cocoons in February, at which time the nests of the summer Resin-bee are occupied by larvae and those of the spring Resin-bee by the perfect insect. If we shrink from this brutal method, we are still in doubt until the cocoons open, so great is the resemblance between the two pieces of work.

In both cases, we find the same lodging, Snail-shells of every size and every kind, just as they happen to come; the same resin lid, the inside gritty with tiny bits of stone, the outside almost smooth and sometimes ornamented with little shells; the same barricade—not always present—of various kinds of rubbish; the same division into two rooms of unequal size occupied by the two sexes. Everything is identical, down to the purveyor of the gum, the brown-berried juniper. To say more about the nest of the summer Resin-bee would be to repeat oneself.

There is only one thing that requires further investigation. I do not see the reason that prompts the two insects to leave the greater part of their shell empty in front, instead of occupying it entirely up to the orifice as the Osmia habitually does. As the mother's laying is broken up into intermittent shifts of a couple of eggs apiece, is it necessary that there should be a new home for each shift? Is the half-fluid resin unsuitable for the wide-spanned roofs which would have to be constructed when the diameter of the helical passage exceeded certain limits? Is the gathering of the cement too wearisome a task to leave the Bee any strength for making the numerous partitions which she would need if she utilized the spacious final whorl? I find no answer to these questions. I note the fact without interpreting it: when the shell is a large one, the front part, almost the whole of the last whorl, remains an empty vestibule.

To the spring Resin-bee, Anthidium septemdentatum, this less than half occupied lodging presents no drawbacks. A contemporary of the Osmia, often her neighbour under the same stone, the gum-worker builds her nest at the same period as the mud-worker; but there is no fear of mutual encroachments, for the two Bees, working next door to each other, watch their respective properties with a jealous eye. If attempts at usurpation were to be made, the owner of the Snail-shell would know how to enforce her rights as the first occupant.

For the summer Resin-bee, A. bellicosum, the conditions are very different. At the moment when the Osmia is building, she is still in the larval, or at most in the nymphal stage. Her abode, which would not be more absolutely silent if deserted, her shell, with its vast untenanted porch, will not tempt the earlier Resin-bee, who herself wants apartments right at the far end of the spiral, but it might suit the Osmia, who knows how to fill the shell with cells up to the mouth. The last whorl left vacant by the Anthidium is a magnificent lodging which nothing prevents the mason from occupying. The Osmia does seize upon it, in fact, and does so too often for the welfare of the unfortunate late-comer. The final resin lid takes the place, for the Osmia, of the mud stopper with which she cuts off at the back the portion of the spiral too narrow for her labours. Upon this lid she builds her mass of cells in so many storeys, after which she covers the whole with a thick defensive plug. In short, the work is conducted as though the Snail-shell contained nothing.

When July arrives, this doubly-tenanted house becomes the scene of a tragic conflict. Those below, on attaining the adult state, burst their swaddling-bands, demolish their resin partitions, pass through the gravel barricade and try to release themselves; those above, larvae still or budding pupae, prisoners in their shells until the following spring, completely block the way. To force a passage from the far-end of those catacombs is beyond the strength of the Resin-bee, already weakened by the effort of breaking out of her own nest. A few of the Osmia's partitions are damaged, a few cocoons receive slight injuries; and then, worn out with vain struggles, the captives abandon hope and perish behind the impregnable wall of earth. And with them perish also certain parasites, even less fit for the prodigious work of clearance: Zonites and Chryses (Chrysis flammea), of whom the first are consumers of provisions and the second of grubs.

This lamentable ending of the Resin-bee, buried alive under the Osmia's walls, is not a rare accident to be passed over in silence or mentioned in a few words; on the contrary, it happens very often; and its frequency suggests this thought: the school which sees in instinct an acquired habit treats the slightest favourable occurrence in the course of animal industry as the starting-point of an improvement which, transmitted by heredity and becoming in time more and more accentuated, at last grows into a settled characteristic common to the whole race. There is, it is true, a total absence of positive proofs in support of this theory; but it is stated with a wealth of hypothesis that leaves a thousand loopholes: 'Granting that...Supposing that...It may be...nothing need prevent us from believing... It is quite possible...' Thus argued the master; and the disciples have not yet hit upon anything better.

'If the sky were to fall,' said Rabelais, 'the larks would all be caught.'

Yes, but the sky stays up; and the larks go on flying.

'If things happened in such and such a way,' says our friend, 'instinct may have undergone variations and modifications.'

Yes, but are you quite sure that things happened as you say?

I banish the word 'if' from my vocabulary. I suppose nothing, I take nothing for granted; I pluck the brutal fact, the only thing that can be trusted; I record it and then ask myself what conclusion rests upon its solid framework. From the fact which I have related we may draw the following inference:

'You say that any modification profitable to the animal is transmitted throughout a series of favoured ones who, better equipped with tools, better endowed with aptitudes, abandon the ancient usages and replace the primitive species, the victim of the struggle for life. You declare that once, in the dim distance of the ages, a Bee found herself by accident in possession of a dead Snail-shell. The safe and peaceful lodging pleased her fancy. On and on went the hereditary liking; and the Snail-shell proved more and more agreeable to the insect's descendants, who began to look for it under the stones, so that later generations, with the aid of habit, ended by adopting it as the ancestral dwelling. Again by accident, the Bee happened upon a drop of resin. It was soft, plastic, well-suited for the partitioning of the Snail-shell; it soon hardened into a solid ceiling. The Bee tried the resinous gum and benefited by it. Her successors also benefited by it, especially after improving it. Little by little, the rubble-work of the lid and of the gravel barricade was invented: an enormous improvement, of which the race did not fail to take advantage. The defensive fortification was the finishing-touch to the original structure. Here we have the origin and development of the instinct of the Resin-bees who make their home in Snail-shells.'

This glorious genesis of insect ways and means lacks just one little thing: probability. Life everywhere, even among the humble, has two phases: its share of good and its share of evil. Avoiding the latter and seeking the former is the rough balance-sheet of life's actions. Animals, like ourselves, have their portion of the sweet and the bitter: they are just as anxious to reduce the second as to increase the first; for, with them as with us,

De malheurs evites le bonheur se compose. (Bad luck missed is good luck gained.)

If the Bee has so faithfully handed down her casual invention of a resin nest built inside a Snail-shell, then there is no denying that she must have just as faithfully handed down the means of averting the terrible danger of belated hatchings. A few mothers, escaping at rare intervals from the catacombs blocked by the Osmiae, must have retained a lively memory, a powerful impression of their desperate struggle through the mass of earth; they must have inspired their descendants with a dread of those vast dwellings where the stranger comes afterwards and builds; they must have taught them by habit the means of safety, the use of the medium-sized shell, which the nest fills to the mouth. So far as the prosperity of the race was concerned, the discontinuance of the system of empty vestibules was far more important than the invention of the barricade, which is not altogether indispensable: it would have saved them from perishing miserably, behind impenetrable walls, and would have considerably increased the numbers of their posterity.

Thousands and thousands of experiments have been made throughout the ages with Snail-shells of average dimensions: the thing is certain, because I find many of them to-day. Well, have these life-saving experiments, with their immense importance to the race, become general by hereditary bequest? Not at all: the Resin-bee persists in using big Snail-shells just as though her ancestors had never known the danger of the Osmia-blocked vestibule. Once these facts are duly recognized, the conclusion is irresistible: it is obvious that, as the insect does not hand down the casual modification tending towards the avoidance of what is to its disadvantage, neither does it hand down the modification leading to the adoption of what is to its advantage. However lively the impression made upon the mother, the accidental leaves no trace in the offspring. Chance plays no part in the genesis of the instincts.

Next to these tenants of the Snail-shells we have two other Resin-bees who never come to the shells for a cabin for their nests. They are Anthidium quadrilobum, LEP., and A. Latreillii, LEP., both exceedingly uncommon in my district. If we meet them very rarely, however, this may well be due to the difficulty of seeing them; for they lead extremely solitary and wary lives. A warm nook under some stone or other; the deserted streets of an Ant-hill in a sun-baked bank; a Beetle's vacant burrow a few inches below the ground; in short, a cavity of some sort, perhaps arranged by the Bee's own care: these are the only establishments which I know them to occupy. And here, with no other shelter than the cover of the refuge, they build a mass of cells joined together and grouped into a sphere, which, in the case of the Four-lobed Resin-bee, attains the size of a man's fist and, in that of Latreille's Resin-bee, the size of a small apple.

At first sight, we remain very uncertain as to the nature of the strange ball. It is brown, rather hard, slightly sticky, with a bituminous smell. Outside are encrusted a few bits of gravel, particles of earth, heads of large-sized Ants. This cannibal trophy is not a sign of barbarous customs: the Bee does not decapitate Ants to adorn her hut. An inlayer, like her colleagues of the Snail-shell, she gathers any hard granule near at hand capable of strengthening her work; and the dried skulls of Ants, which are frequent around about her abode, are in her eyes building-stones of equal value to the pebbles. One and all employ whatever they can find without much seeking. The inhabitant of the shell, in order to construct her barricade, makes shift with the dry excrement of the nearest Snail; the denizen of the flat stones and of the roadside banks frequented by the Ants does what she can with the heads of the defunct and, should these be lacking, is ready to replace them with something else. Moreover, the defensive inlaying is slight; we see that the insect attaches no great importance to it and has every confidence in the stout wall of the home.

The material of which the work is made at first suggests some rustic wax, much coarser than that of the Bumble-bees, or rather some tar of unknown origin. We think again and then recognize in the puzzling substance the semitransparent fracture, the quality of becoming soft when exposed to heat and of burning with a smoky flame, the solubility in spirits of wine—in short, all the distinguishing characteristics of resin. Here then are two more collectors of the exudations of the Coniferae. At the points where I find their nests are Aleppo pines, cypresses, brown-berried junipers and common junipers. Which of the four supplies the mastic? There is nothing to tell us. Nor is there anything to explain how the native amber-colour of the resin is replaced in the work of both Bees by a dark-brown hue resembling that of pitch. Does the insect collect resin impaired by the weather, soiled by the sanies of rotten wood? When kneading it, does it mix some dark ingredient with it? I look upon this as possible, but not as proved, since I have never seen the Bee collecting her resin.

While this point escapes me, another of higher interest appears most plainly; and that is the large amount of resinous material used in a single nest, especially in that of Anthidium quadrilobum, in which I have counted as many as twelve cells. The nest of the Mason-bee of the Pebbles is hardly more massive. For so costly an establishment, therefore, the Resin-bee collects her pitch on the dead pine as copiously as the Mason-bee collects her mortar on the macadamized road. Her workshop no longer shows us the niggardly partitioning of a Snail-shell with two or three drops of resin; what we see is the whole building of the house, from the basement to the roof, from the thick outer walls to the partitions of the rooms. The cement expended would be enough to divide hundreds of Snail-shells, wherefore the title of Resin-bee is due first and foremost to this master-builder in pitch. Honourable mention should be awarded to A. Latreillii, who rivals her fellow-worker as far as her smaller stature permits. The other manipulators of resin, those who build partitions in Snail-shells, come third, a very long way behind.