Harvesting Ants and Trap-Door Spiders / Notes and Observations on Their Habits and Dwellings

by John Traherne Moggridge

Nemesia Eleanora ♂ Adult, natural size.]

Since the above description of the female of this species was written, an example of the adult male has been most opportunely discovered. It is much smaller than the female, its length being only six lines. The Cephalothorax is of an uniform clear yellow-brown colour, tinged with orange, and thinly clothed with a greyish pubescence: the oblique indentations marking the union of the cephalic and thoracic segments are indicated by a strongish black-brown band on either side, which becomes obsolete as each approaches the other near the central curved indentation; there are also two or three converging suffused blackish stripes on the hinder slope. The relative length of the Legs is the same in both sexes, 4, 1, 2, 3, but in the male those of the fourth are longer in proportion to those of the third pair than in the female; the spines also on the legs are more numerous and stronger, the upper sides of the femora of all the legs are deeply suffused with black, while in the female this suffusion is not nearly of so marked a character, though the genua of the different females examined had a strong brown-black macula on the outer side of each, while the corresponding maculæ in the single male examined were but just visible; the three spines observed on the outer side of the genua of the third pair of legs in the female are of even a more marked character in the male, and hence they may be considered a good and tangible specific difference from other nearly allied species; the tibiæ of the first pair are considerably enlarged on the under side at the fore extremity, where each is armed with a single, longish, strong, slightly curved, pointed black spine directed forwards (fig. a, 3). The Abdomen is small and of an oval form; its colours and markings resemble those of the female, but on the hinder half of the upper side two or three indistinctly traced pale angular bars or chevrons are formed by the distribution of the black-brown colours and markings; the under side of the abdomen is of a uniform pale whitish yellow, except the spiracular plates, which are yellow-brown. The Palpi are moderately long and strong; the radial joint is longer than the cubital, and is of a tumid and somewhat oval form, suffused over most of its surface with dark brown, the rest of the palpus being of a yellowish-brown colour; the digital joint is small and somewhat oblong-oval, curved downwards, and very slightly concave on its inside; the palpal organs consist of a nearly globular, basal, corneous bulb prolonged into a strongish, curved, but not very long, pear-stem form, the stem being distinctly cleft or bifid at its extreme point (vide figs. a 1, and a 2), one portion of the bifid part is larger than the other, though both are equal in length, and the stem of the palpal bulb is directed transversely outwards, almost at right angles with the digital joint.

Until the discovery of the male spider now described, and which is, without doubt, the male sex of the female described immediately before, this latter was thought to be the female of Nemesia Manderstjernæ (Ausserer), and it had indeed been so determined by Professor Ausserer himself. But the form of the palpal organs differs so decidedly from those of N. Manderstjernæ (Ausserer, Beiträge ... der Territelariæ, Verhandl. Z. B. Gesllsch: Wien, 1871, Bd. xxi. p. 170), that all doubts as to the present being a distinct (and as it is believed to be) a hitherto undescribed species, are removed. From M. Ausserer's description, the pear shaped stem of the palpal bulb in N. Manderstjernæ is comparatively slender, ending in a fine and uncleft point, whereas, in N. Eleanora, the stem is strong and its extremity cleft: other differences are also observable in the two spiders, but this one is well marked and the most tangible.

The specific name, Eleanora, now conferred upon the species, is taken from the Christian name of the Hon. Mrs. Boyle, reference to whom has been before made, and of whose kind exertions some acknowledgment is thus permanently recorded.

In fig. A, [Plate XII.], the upper door, which, if closed, would be entirely hidden by the long filmy mosses which surround and cover it, is represented open; but it should be clearly understood that this is artificial and not natural, as in reality these doors close of their own accord by means of their weight and the elasticity of the hinge. It will be seen that living mosses of two kinds are worked into the upper surface of this door, which was admirably concealed. (fig. A 1, [Plate XII.]).

It is chiefly in the absence of the branch and the different form of the lower door that the nest of Nemesia Eleanora differs from that of N. meridionalis; and, as they inhabit the same localities, it is only when one has dug down as far as the lower door that it can be known to which of the two species the nest belongs. When once this point is reached however, all doubt is at an end; for in this case the unbranched double-door nest differs from the branched in a way which any child could realize, though the respective spiders are not very dissimilar when seen with the naked eye alone. This affords a good instance of the benefit which may accrue to a collector from a study of the habits of the creatures which he collects, for it is certain that it was the nest in this case which first proclaimed the distinctness of its tenant.

Nemesia Eleanora is rather less common at Mentone than N. meridionalis, but at Cannes I found the reverse to be the case. At the latter place, on the northern slope of the little hill of St. Cassien, branched and unbranched double-door nests may, however, be found in tolerable abundance, the traps being frequently concealed by fallen leaves from the cork oaks, which are woven into their upper surface.

The nest of N. Eleanora often has the upper part of the tube prolonged above the surface of the ground and carried up through mosses, grasses, and the like.

An example of this is seen in figs. B and B 1, [Plate XII.], in which the upper part of the tube is represented with the surface door open in the one case and shut in the other.