in the
mother's hesitation and her obstinacy in settling females in some of my
apparatus which looked as if they could suit none but males.

A suspicion occurs to me, a suspicion aroused by my attentive
examination of the narrow tubes. All, whatever the number of their
inmates, are carefully plugged at the opening, just as separate tubes
would be. It might therefore be the case that the narrow gallery at the
back was looked upon by the Osmia not as the prolongation of the large
front gallery, but as an independent tube. The facility with which
the worker turns as soon as she reaches the wide tube, her liberty of
action, which is now as great as in a doorway communicating with the
outer air, might well be misleading and cause the Osmia to treat the
narrow passage at the back as though the wide passage in front did not
exist. This would account for the placing of the female in the large
tube above the males in the small tube, an arrangement contrary to her
custom.

I will not undertake to decide whether the mother really appreciates the
danger of my snares, or whether she makes a mistake in considering
only the space at her disposal and beginning with males. At any rate,
I perceive in her a tendency to deviate as little as possible from the
order which safeguards the emergence of the two sexes. This tendency is
demonstrated by her repugnance to colonizing my narrow tubes with long
series of males. However, so far as we are concerned, it does not matter
much what passes at such times in the Osmia's little brain. Enough for
us to know that she dislikes narrow and long tubes, not because they are
narrow, but because they are at the same time long.

And, in fact, she does very well with a short tube of the same diameter.
Such are the cells in the old nests of the Mason-bee of the Shrubs
and the empty shells of the Garden Snail. With the short tube, the two
disadvantages of the long tube are avoided. She has very little of that
crawling backwards to do when she has a Snail-shell for the home of
her eggs and scarcely any when the home is the cell of the Mason-bee.
Moreover, as the stack of cocoons numbers two or three at most, the
deliverance will be exempt from the difficulties attached to a long
series. To persuade the Osmia to nidify in a single tube long enough to
receive the whole of her laying and at the same time narrow enough
to leave her only just the possibility of admittance appears to me
a project without the sli