point
in mind, would it be possible for me, by manoeuvring, to obtain an
inversion of this order and make the laying begin with males? I
think so, from the results already ascertained and the irresistible
conclusions to be drawn from them. The double-galleried tubes are
installed in order to put my conjectures to the proof.

The back gallery, 5 or 6 millimetres (.195 to.234 inch.--Translator's
Note.) wide, is too narrow to serve as a lodging for normally developed
females. If, therefore, the Osmia, who is very economical of her space,
wishes to occupy them, she will be obliged to establish males there.
And her laying must necessarily begin here, because this corner is
the rear-most part of the tube. The foremost gallery is wide, with an
entrance-door on the front of the hive. Here, finding the conditions to
which she is accustomed, the mother will go on with her laying in the
order which she prefers.

Let us now see what has happened. Of the fifty-two double galleried
tubes, about a third did not have their narrow passage colonized. The
Osmia closed its aperture communicating with the large passage; and the
latter alone received the eggs. This waste of space was inevitable.
The female Osmiae, though nearly always larger than the males, present
marked differences among one another: some are bigger, some are smaller.
I had to adjust the width of the narrow galleries to Bees of average
dimensions. It may happen therefore that a gallery is too small to admit
the large-sized mothers to whom chance allots it. When the Osmia is
unable to enter the tube, obviously she will not colonize it. She then
closes the entrance to this space which she cannot use and does her
laying beyond it, in the wide tube. Had I tried to avoid these useless
apparatus by choosing tubes of larger calibre, I should have encountered
another drawback: the medium-sized mothers, finding themselves almost
comfortable, would have decided to lodge females there. I had to be
prepared for it: as each mother selected her house at will and as I was
unable to interfere in her choice, a narrow tube would be colonized or
not, according as the Osmia who owned it was or was not able to make her
way inside.

There remain some forty pairs of tubes with both galleries colonized. In
these there are two things to take into consideration. The narrow
rear tubes of 5 or 5 1/2 millimetres (.195 to.214 inch.--Translator's
Note.)--and these are the most numerous--contain male