Page:Harvesting ants and trap-door spiders. Notes and observations on their habits and dwellings (IA harvestingantstr00mogg).pdf/168

 did so, no doubt, in their day, for they are exact copies in miniature of the ordinary horse-shoe shaped lower doors. The lower door actually in use may sometimes be found to have two separable cases of thick silk enclosing the central mass of earth, and this also, very probably, represents enlargement. In the nests of N. meridionalis I have never found any of these abandoned doors behind the one in use, nor should I expect to find any, for if they were present they would permanently obstruct the entrance from the main tube to the branch.

It is clear that it is better economy on the part of the spider to enlarge its nest rather than build a new one each time. If we compare the infant spider and its nest (fig. B, Plate IX., p. 98) with the full-grown creature and its nest (fig. A, Plate IX.), it becomes evident that the growing spider must either construct many nests of intermediate size, or frequently enlarge the original domicile. And we do in fact find nests of all sizes between the two extremes.

I cannot help thinking that these very small nests, built as they are by minute spiders probably not very long hatched from the egg, must rank among the most marvellous structures of the kind with which we are acquainted. That so young and weak a creature should be able to excavate a tube in the earth many times its own length, and know how to make a perfect miniature of the nest of its parents, seems to be a fact which has scarcely a parallel in nature.

When we remember how difficult a thing it is for even a trained draughtsman to reduce by eye a complicated drawing or model to a greatly diminished scale, we must own that the performance of this feat