We now turn from the single-door nests to those with double doors, and from the well known to the new types of structure.
In these we have a thin and wafer-like door at the mouth of the nest, and from two to four inches lower down, a second and solid underground door. These lower doors are characteristic of the nests to which they belong, that of the branched nest (Nemesia meridionalis, [Plate IX.]) being long and more or less tongue-shaped, while that of the unbranched double-door nest (N. Eleanora, [Plate XII.] p. 106) is somewhat horse-shoe shaped.
The surface doors of these two kinds of nest do not appear to differ, and, though rather thinner, may be compared to those of the single-door wafer kind from Jamaica.
The commonest form at Mentone is the branched nest, which may be found in abundance in many of the loosely-built walls of the lemon and olive terraces or on sloping banks, but they are rarely to be met with on flat ground.
In the nests of Nemesia meridionalis the tube, instead of being simple, as it is in all other known nests, is invariably branched, a second tube joining the first at the point where the lower door is hung and forming with it an angle of about 45°. The main tube descends and is frequently curved, or sometimes doubly bent like the spout of a tea-kettle (A, [Plate X.] p. 100), while the branch ascends, and in some few instances reaches the surface, though it is usually a cul de sac ([Plate IX.])
Plate IX.
In the exceptional cases where the nests have two superficial openings, one of the two surface doors always appears neglected and going to decay, or is covered with earth which chokes the upper part of its tube. The explanation of this probably is that the spider found the original entrance blocked up or in some way unfitted for use, and then prolonged what was the blind branch until it reached the surface and replaced the former doorway. However this may be it is certain that in the great majority of nests it will be found that the branch ends in the earth, and is a cul de sac, and this I have invariably observed to be the case in the nests of very young spiders of this species (fig. B, [Plate IX.])
The tube is frequently enlarged at the mouth, and forms a spreading lip which the surface door is usually large enough to cover (A 1, [Plate IX.])