where observed, that constraint is used to retain the queens in
captivity. The bees solder the covering to the sides of the cell by a
cordon of wax. As I have also explained how they are fed, it need not be
repeated here.

It is likewise a very remarkable fact, that queens are set at liberty
earlier or later according to their age. Immediately when the royal
cells were sealed, we marked them all with numbers, and we chose this
period because it indicated the age of the queens exactly. The oldest
was first liberated, then the one immediately younger, and so on with
the rest. None of the younger queens were set at liberty before the
older ones.

I have a thousand times asked myself how the bees could so accurately
distinguish the age of their captives. Undoubtedly I should do better to
answer this question by a simple avowal of my ignorance. At the same
time, I must be permitted to state a conjecture. You will admit, that I
have not, as some authors, abused the right of giving myself up to
hypothesis; may not the humming or sound emitted by the young queens in
their cells, be one of the methods employed by nature to instruct the
bees in the age of their queens? It is certain that the female, whose
cell is first sealed, is also the first to emit this sound. That in the
next emits it sooner than the rest, and so on with those immediately
subsequent. As their captivity may continue six days, it is possible
that the bees in this space of time may forget which has emitted it
first; but it is also possible, that the queens diversify the sounds,
encreasing the loudness as they become older, and that the bees can
distinguish these variations. We have even ourselves been able to
distinguish differences in the sound, either with relation to the
succession of notes, or their intensity; and probably there are
gradations still more imperceptible that escape our organs, but may be
sensible to those of the workers.

What gives weight to this conjecture is, that the queens brought up by
M. Schirach's method, are perfectly mute; neither do the workers form
any guard around their cells, nor do they retain them in captivity a
moment beyond the period of transformation, and, when they have
undergone it, they are allowed to combat until one has become
victorious over all the rest. Why? Because the object is only to replace
the last queen. Now, provided that among the worms reared as queens,
only one succeeds, the fate of the others is unin