he egg which she is about to lay.

The Osmiae themselves will furnish the most conclusive evidence on the
latter point. We have seen that these Bees are not generally miners, who
themselves dig out the foundation of their cells. They make use of the
old structures of others, or else of natural retreats, such as hollow
stems, the spirals of empty shells and various hiding-places in walls,
clay or wood. Their work is confined to repairs to the house, such
as partitions and covers. There are plenty of these retreats; and the
insect would always find first-class ones if it thought of going any
distance to look for them. But the Osmia is a stay-at-home: she returns
to her birth-place and clings to it with a patience extremely difficult
to exhaust. It is here, in this little familiar corner, that she prefers
to settle her progeny. But then the apartments are few in number and of
all shapes and sizes. There are long and short ones, spacious ones and
narrow. Short of expatriating herself, a Spartan course, she has to use
them all, from first to last, for she has no choice. Guided by these
considerations, I embarked on the experiments which I will now describe.

I have said how my study, on two separate occasions, became a populous
hive, in which the Three-horned Osmia built her nests in the various
appliances which I had prepared for her. Among these appliances, tubes,
either of glass or reed, predominated. There were tubes of all lengths
and widths. In the long tubes, entire or almost entire layings, with a
series of females followed by a series of males, were deposited. As I
have already referred to this result, I will not discuss it again. The
short tubes were sufficiently varied in length to lodge one or other
portion of the total laying. Basing my calculations on the respective
lengths of the cocoons of the two sexes, on the thickness of the
partitions and the final lid, I shortened some of these to the exact
dimensions required for two cocoons only, of different sexes.

Well, these short tubes, whether of glass or reed, were seized upon as
eagerly as the long tubes. Moreover, they yielded this splendid result:
their contents, only a part of the total laying, always began with
female and ended with male cocoons. This order was invariable; what
varied was the number of cells in the long tubes and the proportion
between the two sorts of cocoons, sometimes males predominating and
sometimes females.

The experiment is of pa