The method of construction deceives us:  the ceiling is immovable; at no season can my forceps manage to extract it, without destroying the building from top to bottom.  The dehiscence takes place elsewhere, at some point on the sides.  Nothing informs us, nothing suggests to us that it will occur at one place rather than another.

Moreover, to tell the truth, it is not a dehiscence prepared by means of some dainty piece of mechanism; it is a very irregular tear.  Somewhat sharply, under the fierce heat of the sun, the satin bursts like the rind of an over-ripe pomegranate.  Judging by the result, we think of the expansion of the air inside, which, heated by the sun, causes this rupture.  The signs of pressure from within are manifest:  the tatters of the torn fabric are turned outwards; also, a wisp of the russet eiderdown that fills the wallet invariably straggles through the breach.  In the midst of the protruding floss, the Spiderlings, expelled from their home by the explosion, are in frantic commotion.

The balloons of the Banded Epeira are bombs which, to free their contents, burst under the rays of a torrid sun.  To break they need the fiery heat-waves of the dog-days.  When kept in the moderate atmosphere of my study, most of them do not open and the emergence of the young does not take place, unless I myself I have a hand in the business; a few others open with a round hole, a hole so neat that it might have been made with a punch.  This aperture is the work of the prisoners, who, relieving one another in turns, have, with a patient tooth, bitten through the stuff of the jar at some point or other.

When exposed to the full force of the sun, however, on the rosemaries in the enclosure, the balloons burst and shoot forth a ruddy flood of floss and tiny animals.  That is how things occur in the free sun-bath of the fields.  Unsheltered, among the bushes, the wallet of the Banded Epeira, when the July heat arrives, splits under the effort of the inner air.  The delivery is effected by an explosion of the dwelling.

A very small part of the family are expelled with the flow of tawny floss; the vast majority remain in the bag, which is ripped open, but still bulges with eiderdown.  Now that the breach is made, any one can go out who pleases, in his own good time, without hurrying.  Besides, a solemn action has to be performed before the emigration.  The animal must cast its skin; and the moult is an event that does not fall on the same date for all.  The evacuation of the place, therefore, lasts several days.  It is effected in small squads, as the slough is flung aside.

Those who sally forth climb up the neighbouring twigs and there, in the full heat of the sun, proceed with the work of dissemination.  The method is the same as that which we saw in the case of the Cross Spider.  The spinnerets abandon to the breeze a thread that floats, breaks and flies away, carrying the rope-maker with it.  The number of starters on any one morning is so small as to rob the spectacle of the greater part of its interest.  The scene lacks animation because of the absence of a crowd.