he orifice of the bag. In the same way, the lid of a
saucepan fits the mouth by means of a projecting rim, with this
difference, that the rim is not attached to the saucepan, whereas, in the
Epeira's work, it is soldered to the bag or nest. Well, at the time of
the hatching, this disk becomes unstuck, lifts and allows the new-born
Spiders to pass through.

If the rim were movable and simply inserted, if, moreover, the birth of
all the family took place at the same time, we might think that the door
is forced open by the living wave of inmates, who would set their backs
to it with a common effort. We should find an approximate image in the
case of the saucepan, whose lid is raised by the boiling of its contents.
But the fabric of the cover is one with the fabric of the bag, the two
are closely welded; besides, the hatching is effected in small batches,
incapable of the least exertion. There must, therefore, be a spontaneous
bursting, or dehiscence, independent of the assistance of the youngsters
and similar to that of the seed-pods of plants.

When fully ripened, the dry fruit of the snap-dragon opens three windows;
that of the pimpernel splits into two rounded halves, something like
those of the outer case of a fob-watch; the fruit of the carnation partly
unseals its valves and opens at the top into a star-shaped hatch. Each
seed-casket has its own system of locks, which are made to work smoothly
by the mere kiss of the sun.

Well, that other dry fruit, the Banded Epeira's germ-box, likewise
possesses its bursting-gear. As long as the eggs remain unhatched, the
door, solidly fixed in its frame, holds good; as soon as the little ones
swarm and want to get out, it opens of itself.

Come June and July, beloved of the Cicadae, no less beloved of the young
Spiders who are anxious to be off. It were difficult indeed for them to
work their way through the thick shell of the balloon. For the second
time, a spontaneous dehiscence seems called for. Where will it be
effected?

The idea occurs off-hand that it will take place along the edges of the
top cover. Remember the details given in an earlier chapter. The neck
of the balloon ends in a wide crater, which is closed by a ceiling dug
out cup-wise. The material is as stout in this part as in any other;
but, as the lid was the finishing touch to the work, we expect to find an
incomplete soldering, which would allow it to be unfastened.

The method of construction