the natural partitions; this is an advantage, as we shall see. In any
case, I could not well use thinner ones, for these disks must be able
to withstand the pressure of the rammer which places them in position
in the tube. On the other hand, the experiment showed me that the
Osmia makes short work of the material when it is a case of drilling
a hole through it.

To keep out the light, which would disturb my insects destined to
spend their larval life in complete darkness, I cover the tube with a
thick paper sheath, easy to remove and replace when the time comes
for observation. Lastly, the tubes thus prepared and containing
either Osmiae or other bramble-dwellers are hung vertically, with the
opening at the top, in a snug corner of my study. Each of these
appliances fulfils the natural conditions pretty satisfactorily: the
cocoons from the same bramble-stick are stacked in the same order
which they occupied in the native shaft, the oldest at the bottom of
the tube and the youngest close to the orifice; they are isolated by
means of partitions; they are placed vertically, head upwards;
moreover, my device has the advantage of substituting for the opaque
wall of the bramble a transparent wall which will enable me to follow
the hatching day by day, at any moment which I think opportune.

The male Osmia splits his cocoon at the end of June and the female at
the beginning of July. When this time comes, we must redouble our
watch and inspect the tubes several times a day if we would obtain
exact statistics of the births. Well, during the six years that I
have studied this question, I have seen and seen again, ad nauseam;
and I am in a position to declare that there is no order governing
the sequence of hatchings, absolutely none. The first cocoon to burst
may be the one at the bottom of the tube, the one at the top, the one