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The Life of the Spider

The Garden Spiders: The Lime-Snare
The spiral network of the Epeirae possesses contrivances of fearsome cunning. Let us
give our attention by preference to that of the Banded Epeira or that of the Silky Epeira,
both of which can be observed at early morning in all their freshness.
The thread that forms them is seen with the naked eye to differ from that of the
framework and the spokes. It glitters in the sun, looks as though it were knotted and
gives the impression of a chaplet of atoms. To examine it through the lens on the web
itself is scarcely feasible, because of the shaking of the fabric, which trembles at the least
breath. By passing a sheet of glass under the web and lifting it, I take away a few pieces
of thread to study, pieces that remain fixed to the glass in parallel lines. Lens and
microscope can now play their part.
The sight is perfectly astounding. Those threads, on the borderland between the visible
and the invisible, are very closely twisted twine, similar to the gold cord of our officers’
sword-knots. Moreover, they are hollow. The infinitely slender is a tube, a channel full
of a viscous moisture resembling a strong solution of gum arabic. I can see a diaphanous
trail of this moisture trickling through the broken ends. Under the pressure of the thin
glass slide that covers them on the stage of the microscope, the twists lengthen out,
become crinkled ribbons, traversed from end to end, through the middle, by a dark streak,
which is the empty container.
The fluid contents must ooze slowly through the side of those tubular threads, rolled into
twisted strings, and thus render the network sticky. It is sticky, in fact, and in such a way
as to provoke surprise. I bring a fine straw flat down upon three or four rungs of a
sector. However gentle the contact, adhesion is at once established. When I lift the
straw, the threads come with it and stretch to twice or three times their length, like a
thread of India-rubber. At last, when over-taut, they loosen without breaking and resume
their original form. They lengthen by unrolling their twist, they shorten by rolling it
again; lastly, they become adhesive by taking the glaze of the gummy moisture
wherewith they are filled.
In short, the spiral thread is a capillary tube finer than any that our physics will ever
know. It is rolled into a twist so as to possess an elasticity that allows it, without
breaking, to yield to the tugs of the captured prey; it holds a supply of sticky matter in
reserve in its tube, so as to renew the adhesive properties of the surface by incessant
exudation, as they become impaired by exposure to the air. It is simply marvellous.
The Epeira hunts not with springs, but with lime-snares. And such lime-snares!
Everything is caught in them, down to the dandelion-plume that barely brushes against
them. Nevertheless, the Epeira, who is in constant touch with her web, is not caught in
them. Why?
 
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