remarkable observations which their conjectures have induced me to make, and then describe the new experiments by which I think I have solved the problemC.

Swammerdam, who studied bees with unremitting attention, and who never could see a real copulation between a drone and a queen, was satisfied that copulation was unnecessary for fecundation of the eggs: but having remarked that, at certain times, the drones exhaled a very strong odour,   he thought this odour was an emanation of the aura seminalis, or the aura seminalis itself, which operated fecundation by penetrating the body of the female. His conjecture was confirmed on dissecting the male organs of generation; for he was so much struck with the disproportion between them and those of the female, that he did not believe copulation possible. His opinion, concerning the influence of the odour, had this farther advantage, that it afforded a good reason for the prodigious number of the males. There are frequently fifteen hundred or two thousand in a hive; and, according to Swammerdam, it is necessary they should be numerous, that the emanation proceeding from them may have an intensity or energy sufficient to effect impregnation.

Though M. de Reaumur has refuted this hypothesis by just and conclusive reasoning, he has failed to make the sole experiment that could support or overturn it. This was to confine all the drones of a   hive in a tin case, perforated with minute holes, which might allow the emanation of the odour to escape, but prevent the organs of generation from passing through. Then, this case should have been placed in a hive well inhabited, but completely deprived of males, both of large and small size, and the consequence attended to. It is evident, had the queen laid eggs after matters were thus disposed, that Swammerdam's hypothesis would have acquired probability; and on the contrary it would have been confuted had she produced no eggs, or only sterile ones. However the experiment has been made by us, and the queen remained barren; therefore, it is undoubted, that the emanation of the odour of the males does not impregnate bees.

M. de Reaumur was of a different opinion. He thought that the queen's fecundation followed actual copulation. He confined several drones in a glass vessel along with a virgin queen: he saw the female make many advances to the males;   but, unable to observe any union so intimate that it could be denominated copulation, he leaves the question undecided. We have repeated this experiment: we have frequently confined virgin queens with drones of all ages: we have done so at every season, and witnessed all their advances and solicitations to the males: we have even believed we saw a kind of union between them, but so short and imperfect that it was unlikely to effect impregnation. Yet, to neglect nothing, we confined the virgin queen, that had suffered the approaches of the male, to her hive. During a month that her imprisonment continued, she did not lay a single egg; therefore, these momentary junctions do not accomplish fecundation.

In the Contemplation de la Nature, you have cited the observations of the English naturalist Mr Debraw. They appear correct, and at last to elucidate the mystery. Favoured by chance, the observer one day perceived at the bottom of cells containing   eggs, a whitish fluid, apparently spermatic, at least, very different from the substance or jelly which bees commonly collect around their new hatched worms. Solicitous to learn its origin, and conjecturing that it might be the male prolific fluid, he began to watch the motions of every drone in the hive, on purpose to seize the moment when they would bedew the eggs. He assures us, that he saw several insinuate the posterior part of the body into the cells, and there deposit the fluid. After frequent repetition of the first, he entered on a long series of experiments. He confined a number of workers in glass bells along with a queen and several males. They were supplied with pieces of comb containing honey, but no brood. He saw the queen lay eggs, which were bedewed by the males, and from which larvæ were hatched, consequently, he could not hesitate advancing as a fact demonstrated, that male bees fecundate the queen's eggs in   the manner of frogs and fishes, that is, after they are produced.

There was something very specious in this explanation: the experiments on which it was founded seemed correct; and it afforded a satisfactory reason for the prodigious number of males in a hive. At the same time, the author had neglected to answer one strong objection. Larvæ appear when there are no drones. From the month of September until April, hives are generally destitute of males, yet, notwithstanding their absence, the queen then lays fertile eggs. Thus, the prolific fluid cannot be required to impregnate them, unless we can suppose that it is necessary at a certain time of the year, while at every other season it is useless.

To discover the truth amidst these facts apparently so contradictory, I wished to repeat Mr Debraw's experiments, and to observe more precaution than he himself had done. First, I sought for the fluid, which he supposes the seminal, in cells   containing eggs. Several were actually found with that appearance; and, during the first days of observation, neither my assistant nor myself doubted the reality of the discovery. But we afterwards found it an illusion arising from the reflection of the light, for nothing like a fluid was visible, except when the solar rays reached the bottom of the cells. Fragments of the coccoons of worms, successively hatched, commonly cover the bottom; and, as they are shining, it may easily be conceived that, when much illuminated, an illusory effect results from the light. We proved it by the strictest examination, for no vestiges of a fluid were perceptible when the cells were detached and cut asunder.

Though the first observation inspired us with some distrust of Mr Debraw's discovery, we repeated his other experiments with the utmost care. On the 6. of August 1787, we immersed a hive, and, with scrupulous attention, examined the whole bees while in the bath. We ascertained   that there was no male, either large or small; and having examined all the combs, we found neither male nymph, nor worm. When the bees were dry, we replaced them all, along with the queen, in their habitation, and transported them into my cabinet. They were allowed full liberty; therefore, they flew about, and made their usual collections; but, it being necessary that no male should enter the hive during the experiment, a glass tube was adapted to the entrance, of such dimensions that two bees only could pass at once; and we watched the tube attentively during the four or five days that the experiment continued. We should have instantly observed and removed any male that appeared, that the result of the experiment might be undisturbed, and I can positively affirm that not one was seen. However, from the first day, which was the sixth of August, the queen deposited fourteen eggs in the workers cells; and all these   were hatched on the tenth of the same month.

This experiment is decisive, since the eggs laid by the queen of a hive where there were no males, and where it was impossible one could be introduced, since these eggs, I say, were fertile, it becomes indubitable that the fluid of the males is not required for their exclusion.