smia's nests, transferred their
contents into glass tubes and made a careful summary of the sexes.
I give some of my results. The figures start in their order from the
bottom of the tunnel dug in the bramble and proceed upwards to the
orifice. The figure 1 therefore denotes the first-born of the series,
the oldest in date; the highest figure denotes the last-born. The letter
M, placed under the corresponding figure, represents the male and the
letter F the female sex.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 F F M F M F M M F F F F M F M

This is the longest series that I have ever been able to procure. It is
also complete, inasmuch as it comprises the entire laying of the Osmia.
My statement requires explaining, otherwise it would seem impossible to
know whether a mother whose acts one has not watched, nay more, whom
one has never seen, has or has not finished laying her eggs. The
bramble-stump under consideration leaves a free space of nearly four
inches above the continuous string of cocoons. Beyond it, at the actual
orifice, is the terminal stopper, the thick plug which closes the
entrance to the gallery. In this empty portion of the tunnel there is
ample accommodation for numerous cocoons. The fact that the mother has
not made use of it proves that her ovaries were exhausted; for it is
exceedingly unlikely that she has abandoned first-rate lodgings to
go laboriously digging a new gallery elsewhere and there continue her
laying.

You may say that, if the unoccupied space marks the end of the laying,
nothing tells us that the beginning is actually at the bottom of the
cul-de-sac, at the other end of the tunnel. You may also say that the
laying is done in shifts, separated by intervals of rest. The space left
empty in the channel would mean that one of these shifts was finished
and not that there were no more eggs ripe for hatching. In answer
to these very plausible explanations, I will say that, the sum of my
observations--and they have been extremely numerous--is that the total
number of eggs laid not only by the Osmiae but by a host of other Bees
fluctuates round about fifteen.

Besides, when we consider that the active life of these insects lasts
hardly a month; when we remember that this period of activity is
disturbed by dark, rainy or very windy days, during which all work is
suspended; when lastly we ascertain, as I have done ad nauseam in the
case of the Three-horned Osmia, the time required for building and