Lastly, it was a matter of learning the behaviour, after their act of violence, of the Masons who have smashed in a door, brutally expelled the egg within and replaced it by one of their own laying. When the lid is repaired to look as good as new and everything restored to order, will they continue their burglarious ways and exterminate the eggs of others to make room for their own? By no means. Revenge, that pleasure of the gods and perhaps also of Bees, is satisfied after one cell has been ripped open. All anger is appeased when the egg for which so much work has been done is safely housed. Henceforth, both prisoners and stray laggards resume their ordinary labours, indifferently with the rest. They build honestly, they provision honestly, nor meditate further evil. The past is quite forgotten until a fresh disaster occurs.
To return to the parasites: a mother chanced to find herself the mistress of another's nest. She took advantage of this to entrust her egg to it. This expeditious method, so easy for the mother and so favourable to the success of her offspring, made such an impression on her that she transmitted the maternal indolence to her posterity. Thus the worker gradually became transformed into a parasite.
Capital! The thing goes like clockwork, as long as we have only to put our ideas on paper. But let us just consult the facts, if you don't mind; before arguing about probabilities, let us look into things as they are. Here is the Mason-bee of the Sheds teaching us something very curious. To smash the lid of a cell that does not belong to her, to throw the egg out of doors and put her own in its place is a practice which she has followed since time began. There is no need of my interference to make her commit burglary: she commits it of her own accord, when her rights are prejudiced as the result of a too-long absence. Ever since her race has been kneading cement, she has known the law of retaliation. Countless ages, such as the evolutionists require, have made her adopt forcible usurpation as an inveterate habit. Moreover, robbery is so incomparably easy for the mother. No more cement to scratch up with her mandibles on the hard ground, no more mortar to knead, no more clay walls to build, no more pollen to gather on hundreds and hundreds of journeys. All is ready, board and lodging. Never was a better opportunity for allowing one's self a good time. There is nothing against it. The others, the workers, are imperturbable in their good-humour. Their outraged cells leave them profoundly indifferent. There are no brawls to fear, no protests. Now or never is the moment to tread the primrose path.
Besides, your progeny will be all the better for it. You can choose the warmest and wholesomest spots; you can multiply your laying-operations by devoting to them all the time that you would have to spend on irksome occupations. If the impression produced by the violent seizure of another's property is strong enough to be handed down by heredity, how deep should be the impression of the actual moment when the Mason-bee is in the first flush of success! The precious advantage is fresh in the memory, dating from that very instant; the mother has but to continue in order to create a method of installation favourable in the highest degree to her and hers. Come, poor Bee! Throw aside your exhausting labours, follow the evolutionists' advice and, as you have the means at your disposal, become a parasite!
But no, having effected her little revenge, the builder returns to her masonry, the gleaner to her gleaning, with unquenchable zeal. She forgets the crime committed in a moment of anger and takes good care not to hand down any tendency towards idleness to her offspring. She knows too well that activity is life, that work is the world's great joy. What myriads of cells has she not broken open since she has been building; what magnificent opportunities, all so clear and conclusive, has she not had to emancipate herself from drudgery! Nothing could convince her: born to work, she persists in an industrious life. She might at least have produced an offshoot, a race of housebreakers, who would invade cells by demolishing doors. The Stelis does something of the kind; but who would think of proclaiming a relationship between the Chalicodoma and her? The two have nothing in common. I call for a scion of the Mason-bee of the Sheds who shall live by the art of breaking through ceilings. Until they show me one, the theorists will only make me smile when they talk to me of erstwhile workers relinquishing their trade to become parasitic sluggards.
I also call, with no less insistence, for a descendant of the Three-horned Osmia, a descendant given to demolishing party-walls. I will describe later how I managed to make a whole swarm of these Osmiae build their nests on the table in my study, in glass tubes that enabled me to see the inmost secrets of the work of the Bee. (Cf. "Bramble-bees and Others", by J. Henri Fabre, translated by Alexander Teixeira de Mattos: chapters 1 to 7.—Translator's Note.) For three or four weeks, each Osmia is scrupulously faithful to her tube, which is laboriously filled with a set of chambers divided by earthen partitions. Marks of different colours painted on the thorax of the workers enable me to recognize individuals in the crowd. Each crystal gallery is the exclusive property of one Osmia; no other enters it, builds in it or hoards in it. If, through heedlessness, through momentary forgetfulness of her own house in the tumult of the city, some neighbour so much as comes and looks in at the door, the owner soon puts her to flight. No such indiscretion is tolerated. Every Bee has her home and every home its Bee.
All goes well until just before the end of the work. The tubes are then closed at the orifice with a thick plug of earth; nearly the whole swarm has disappeared; there remain on the spot a score of tatterdemalions in threadbare fleeces, worn out by a month's hard toil. These laggards have not finished their laying. There is no lack of unoccupied tubes, for I take care to remove some of those which are full and to replace them by others that have not yet been used. Very few of the Bees decide to take possession of these new homes, which differ in no particular from the earlier ones; and even then they build only a small number of cells, which are often mere attempts at partitions.
They want something different: a nest belonging to some one else. They bore through the stopper of the inhabited tubes, a work of no great difficulty, for we have here not the hard cement of the Chalicodoma, but a simple lid of dried mud. When the entrance is cleared, a cell appears, with its store of provisions and its egg, with her brutal mandibles; she rips it open and goes and flings it away. She does worse: she eats it on the spot. I had to witness this horror many times over before I could accept it as a fact. Note that the egg devoured may very well contain the criminal's own offspring. Imperiously swayed by the needs of her present family, the Osmia puts her past family entirely out of her mind.
Having perpetrated this child-murder, the depraved creature does a little provisioning. They all experience the same necessity to go backwards in the sequence of actions in order to pick up the thread of their interrupted occupations. Her next work is to lay her egg and then she conscientiously restores the demolished lid.
The havoc can be more sweeping still. One of these laggards is not satisfied with a single cell; she needs two, three, four. To reach the most remote, the Osmia wrecks all those which come before it. The partitions are broken down, the eggs eaten or thrown away, the provisions swept outside and often even carried to a distance in great lumps. Covered with dust from the loose plaster of the demolition, floured all over with the rifled pollen, sticky with the contents of the mangled eggs, the Osmia, while at her brigand's work, is altered beyond recognition. Once the place is cleared, everything resumes its normal course. Provisions are laboriously brought to take the place of those which have been thrown away; eggs are laid, one on each heap of food; the partitions are built up again; and the massive plug sealing the whole structure is made as good as new.