The Spiders' Exodus
Next to the tuft, the wing is the most satisfactory contrivance for dissemination by wind. Thanks to their membranous edge, which gives them the appearance of thin scales, the seeds of the yellow wall-flower reach high cornices of buildings, clefts of inaccessible rocks, crannies in old walls, and sprout in the remnant of mould bequeathed by the mosses that were there before them.
The samaras, or keys, of the elm, formed of a broad, light fan with the seed cased in its centre; those of the maple, joined in pairs and resembling the unfurled wings of a bird; those of the ash, carved like the blade of an oar, perform the most distant journeys when driven before the storm.
Like the plant, the insect also sometimes possesses travelling-apparatus, means of dissemination that allow large families to disperse quickly over the country, so that each member may have his place in the sun without injuring his neighbour; and these apparatus, these methods vie in ingenuity with the elm's samara, the dandelion-plume and the catapult of the squirting cucumber.
Let us consider, in particular, the Epeiræ,
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