Plate X., p. 100, fig. A.--Part of a nest of _N. meridionalis_; B, the new and larger upper door of a nest of this spider, with the former and smaller upper door partially united to it; C, another example of enlargement in the upper door of the same spider, showing traces of two previous doors now incorporated. [All the figures are of the natural size.] Plate XI., p. 105, fig. A.--The upper part of a nest of _N. meridionalis_ concealed in a plant of Ceterach fern; A 1 and A 2, a minute cork-door, closed and open, which I saw constructed by a very young spider [either _Cteniza fodiens_, or, more probably, _Nemesia cæmentaria_] at the mouth of a hole in the mass of earth containing the nest of _N. meridionalis_ figured at A. This hole may be seen on the right of the fern. B, the door of a small nest of _N. meridionalis_, as seen from above, in its natural position in a steeply sloping bank; B 1, part of the same nest placed in an upright position, and showing the surface door open and the lower door closing the branch; B 2, the same with the lower door pushed across so as to close the main tube; B 3, 4, and 5, different views of this second door. [All the figures in this plate are of the natural size.] Plate XII., p. 106, fig. A.--The nest of _N. Eleanora_ with the surface door artificially represented as being open; A 1, the outer side of the surface door of the same nest into which mosses of two kinds are woven; A 2, the second door of the same nest; A 3, the spider; A 4, the same deprived of its legs, from a specimen preserved in spirits [figs. A, A 1, 2, 3, and 4 are of the natural size]; fig. A 5, the spider viewed sideways, with the legs removed; A 6, the eyes viewed from above and in front; A 7, the cephalothorax and falces; A 8, the left-hand falx viewed from the inner side; A 9, the fang of the same; A 10, the tarsal joint of the foremost right leg; A 11, one of the two larger and the smallest claw of the same [figs. A 5, 6, 7, 8, 9, 10, and 11, magnified]; fig. B and B 1, the upper part of the tube and door of a nest of _N. Eleanora_ which partially projected beyond the surface of the earth and was clothed with living moss. [Figs. B and B 1 are of the natural size.] PART I. HARVESTING ANTS. PART I. HARVESTING ANTS. It was in May, 1869, that Mr. Bentham in his presidential address to the Linnean Society called attention to the want of reliable information as to the existence of such subterranean accumulations of seeds as are popularly supposed to account for the sudden appearance on railway cuttings, gravel from deep pits, and the like, of crops of weeds hitherto unknown in a district.