The grubs are white, tapering at both ends, sharply segmented and covered all over their bodies with a coat of fine, soft hairs which is invisible except under the lens. The head consists of a little knob much smaller in diameter than the body. In this head, the microscope reveals mandibles consisting of fine spikes of a tawny red, which spread into a wide, colorless base. Deprived of any indentation, incapable of chewing anything between their awl-shaped ends, these two tools serve at best to fix the grub slightly at some point of the fostering larva. Useless for carving, therefore, the mouth is a pure osculatory sucker, which drains the provisions by a process of exudation through the skin. We see here repeated what the Anthrax and the Leucospis have already shown us: the gradual exhaustion of a victim which the parasite consumes without killing it.
It is a curious spectacle even after that of the Anthrax. We have here twenty or thirty starvelings, all with their mouths pressed, as for a kiss, to the body of the plump larva, which, from day to day, fades and shrinks without the least appreciable wound, thus keeping fresh until reduced to a shriveled slough. If I disturb the gluttonous swarm, all, with a sudden recoil, let go, drop off and flounder around the foster mother. They are no less prompt in resuming their savage kisses. I need not add that neither at the point where they leave off nor at the point where they recommence is there the faintest trace of liquid. The oily exudation occurs only when the pump is at work. To linger over this strange method of feeding is superfluous after what I have said about the Anthrax.
The appearance of the full grown insect takes place at the beginning of summer, after nearly a whole year's stay in the invaded dwelling. The large number of inhabitants of one and the same cell led me to think that the work of deliverance ought to present a certain interest. They are all equally anxious to clear the walls of the prison at the earliest possible moment and to come forth into the great festival of the sun: do they all at the same time, in a confused horde, attack the ceiling which has to be pierced? Is the work of deliverance arranged in the general interest? Or is individual selfishness the only rule? These are the questions which observation will answer.
A little in advance of the proper season, I transfer each family into a short glass tube, which will represent the natal cell. Agood, thick cork, quite a centimeter deep, is the obstacle to be pierced for an outlet. Well, instead of the mad haste and the ruinous lack of organization which I expected to find, my broods show me in their glass prison an exceedingly well regulated workshop. One insect, one only, works at perforating the cork.
Patiently, with its mandibles, grain by grain, it digs a tunnel the width of its body. The gallery is so narrow that, in order to return to the tube, the worker has to move backwards. It is a slow process; and it takes hours and hours to dig the hole, a hard job for the frail miner.
Should her fatigue become too great, the excavator leaves the forefront and mingles with the crowd, to polish and dust herself.
Another, the first neighbor at hand, at once takes her place and is herself relieved by a third when her task is done. Others again take their turn, always one at a time, so much so that the works are never at a standstill and never overcrowded. Meanwhile, the multitude keeps out of the way, quietly and patiently. There is no anxiety as to the deliverance. Success will come: of that they are all convinced. While waiting, one washes her antennae by passing them through her mouth, another polishes her wings with her hind legs, another frisks about to while away the period of inaction.
Some are making love, a sovran means of killing time, whether one be born that day or twenty years ago.
Some, I said, make love. These favored ones are rare; they hardly count. Is it through indifference? No, but the gallants are lacking. The sexes are very unequally represented in the population of a cell: the males are in a wretched minority and sometimes even completely absent. This poverty did not escape the older observers. Brulle [Gaspard August Bru11e (1809-1873)], the author of many works on natural history and one of the founders of the Societe entomologique de France), the only author whom I am able to consult in my hermitage, says, literally: 'The males do not appear to be known.'
I, for my part, know them; but, considering their feeble number, Ikeep asking myself what part they play in a harem so disproportionate to their forces. A few figures will show us what my hesitations are based upon.
In twenty-two Osmia cocoons (Osmia tricornis), the total census of the inmates yields three hundred and fifty-four, of whom forty-seven are males and three hundred and seven females. The average number of inmates, therefore, is sixteen individuals; and there are six females at least to one male. This disparity is maintained, in more or less marked proportions, whatever the species of the bee invaded. In the cocoons of the Mason bee of the Sheds, I discover the average proportion to be six females to one male; in those of the Mason bee of the Walls, I find one male to fifteen females.
These facts, which I am unable to state with any greater precision, are enough to give rise to the suspicion that the males, who are even tinier dwarfs than the females and who, moreover, like all insects, are injured by a single act of pairing, must, in most cases, remain strangers to the females. Can the mothers, in fact, dispense with their assistance, without being deprived of offspring on that account? I do not say yes, but I do not say no. The duality of the sexes is a hard problem. Why two sexes? Why not just one? It would have been much simpler and saved a great deal of foolery. Why such a thing as sex, when the tuber of the Jerusalem artichoke can do without it? These are the pregnant questions suggested to me, in the end, by Monodontomerus cupreus, the insect so infinitesimal in body and so overpowering in name that I had really vowed never to speak of it again by its official designation.
