Her family consists of fourteen cocoons, a number very near the average; and, of these fourteen cocoons, twelve belong to males and only two to females.
Another, between the 9th and 27th of May, stocked six Snail-shells with a family of thirteen, including ten males and three females.
A third, between the 2nd and 29th of May colonized eleven Snail-shells, a prodigious task.

This industrious one was also exceedingly prolific.
She supplied me with a family of twenty-six, the largest which I have ever obtained from one Osmia.

Well, this abnormal progeny consisted of twenty-five males and one female.
There is no need to go on, after this magnificent example, especially as the other series would all, without exception, give us the same result.

Two facts are immediately obvious: the Osmia is able to reverse the order of her laying and to start with a more or less long series of males before producing any females.

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.