just possible that their early eclosion forces this method of exit
upon them, a method which, though often attempted, does not always
succeed. The females, furnished with stronger tools, make greater
progress in my tubes. I see some who pierce three or four partitions,
one after the other, and are so many stages ahead before those whom
they have left behind are even hatched. While they are engaged in
this long and toilsome operation, others, nearer to the orifice, have
cleared a passage whereof those from a distance will avail
themselves. In this way, it may happen that, when the width of the
tube permits, an Osmia in a back row will nevertheless be one of the
first to emerge.

In the bramble-stem, which is of exactly the same diameter as the
cocoon, this escape by the side of the column appears hardly
practicable, except to a few males; and even these have to find a
wall which has so much pith that by removing it they can effect a
passage. Let us then imagine a tube so narrow as to prevent any exit
save in the natural sequence of the cells. What will happen? A very
simple thing. The newly-hatched Osmia, after perforating his
partition, finds himself faced with an unbroken cocoon that obstructs
the road. He makes a few attempts upon the sides and, realizing his
impotence, retires into his cell, where he waits for days and days,
until his neighbour bursts her cocoon in her turn. His patience is
inexhaustible. However, it is not put to an over long test, for
within a week, more or less, the whole string of females is hatched.

When two neighbouring Osmiae are released at the same time, mutual
visits are paid through the aperture between the two rooms: the one
above goes down to the floor below; the one below goes up to the
floor above; sometimes both of them are in the same cell together.