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first case, the first female appears as number 7; in the third, as number 17. There is something better still; and this is the proposition which I was particularly anxious to prove: the female sex can be permuted with the male sex and can be permuted to the point of disappearing altogether. We see this especially in the third case, where the presence of a solitary female in a family of twenty-six is due to the somewhat larger diameter of the corresponding Snail-shell and also, no doubt, to some mistake on the mother's part, for the female cocoon, in a series of two, occupies the upper storey, the one next to the orifice, an arrangement which the Osmia appears to me to dislike.
This result throws so much light on one of the darkest corners of biology that I must attempt to corroborate it by means of even more conclusive experiments. I propose next year to give the Osmiae nothing but Snail-shells for a lodging, picked out one by one, and rigorously to deprive the swarm of any other retreat in which the laying could be effected. Under these conditions, I ought to obtain nothing but males, or nearly, for the whole swarm.
There would still remain the inverse permutation: to obtain only females and no males, or very few. The first permutation makes the second seem very probable, although I cannot as yet conceive a means of realizing it. The only condition which I can regulate is the dimensions of the home. When the rooms are small, the males abound and the females tend to disappear. With generous quarters, the converse would not take place. I should obtain females and afterwards an equal number of males, confined in small cells which, in case of need, would be bounded by numerous partitions. The factor of space does not enter into the question here. What artifice can we then employ to provoke this second permutation? So far, I can think of nothing that is worth attempting.
It is time to conclude. Leading a retired life, in the solitude of a village, having quite enough to do with patiently and obs