Page:Harvesting ants and trap-door spiders. Notes and observations on their habits and dwellings (IA harvestingantstr00mogg).pdf/169

 by a baby spider is so surprising as almost to exceed belief.

And yet even the most complicated form of nest—namely, that of the branched double-door type—is perfectly reproduced in miniature by these tiny architects, with the upper door, lower door, main tube, and branch (fig. B, Plate IX., p. 98).

In order to test whether the doors are enlarged or not I measured the surface doors of seven double-door nests and one minute cork door on April 30th, making a careful plan of the terrace wall in which they lay, in order to make sure of finding them again on my return to Mentone in October.

The following table will show that all were enlarged, the average rate of increase being 1-7/10 lines in the five and a half months which had elapsed:—

Measured April 30, 1872.    Measured Oct. 18, 1872.

No. I. 9 lines across       No. I. 10-1/2 lines across II. 4     "                 II. 5-1/2       " III. 4-1/2 "                III. 5-1/2       " IV. 4     "                 IV. 4-1/2       " V. 2     "                  V. 3           " VI. 2-1/2 "                 VI. missing  VII. 1      "  (the cork)    VII. 2 lines across VIII. 5     "               VIII. 7-1/2       "

We can scarcely venture from such limited premises to draw any precise conclusions, but if we suppose that during the entire course of the year the nests increase on an average by about four lines in diameter, and assume that the rate of growth continue the same, the nest of the infant spider, whose surface door measures scarcely a line across, would still require four years to attain the dimensions of some of the largest double-door nests, whose surface doors measure sixteen lines across.