nority. The greater number left the tubes to come to
the shells and then went back from the shells to the tubes. All, after
filling the spiral staircase with two or three cells, closed the house
with a thick earthen stopper on a level with the opening. It was a long
and troublesome task, in which the Osmia displayed all her patience as
a mother and all her talents as a plasterer. There were even some who,
scrupulous to excess, carefully cemented the umbilicus, a hole which
seemed to inspire them with distrust as being able to give access to the
interior of the dwelling. It was a dangerous-looking cavity, which for
the greater safety of the family it was prudent to block up.

When the pupae are sufficiently matured, I proceed to examine
these elegant abodes. The contents fill me with joy: they fulfil my
anticipations to the letter. The great, the very great majority of the
cocoons turn out to be males; here and there, in the bigger cells, a
few rare females appear. The smallness of the space has almost done away
with the sixty-eight Snail-shells colonized. But, of this total number,
I must use only those series which received an entire laying and
were occupied by the same Osmia from the beginning to the end of
the egg-season. Here are a few examples, taken from among the most
conclusive.

From the 6th of May, when she started operations, to the 25th of
May, the date at which her laying ceased, the Osmia occupied seven
Snail-shells in succession. 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. These occupy the seventh and
thirteenth places in chronological order.

Another, between the 9th and 27th of May, stocked six Snail-shells with
a family of thirteen, including ten males and three females. The places
occupied by the latter in the series were numbers 3, 4 and 5.

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, one alone, occupying place 17.

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 revers