It is most likely, however, that the spider knows what she is about and that a door to her dwelling would be the reverse of an advantage to her, for she is more powerful and swifter than the generality of European trap-door spiders, and, as she probably lives by leaping out upon and hunting her prey, she no doubt needs to have the entrance to her nest free of all encumbrance.
I am indebted to the Rev. W. G. Brackenridge for evidence of the very interesting fact that Lycosa narbonensis closes her nest at Cannes in the winter.
I was aware that Latreille stated that the Tarantula possessed this habit,[147] and I was anxious to know whether the species which I had detected at Cannes, inhabiting as it did open nests in the month of May, would also exhibit this curious custom. Being unable to visit Cannes myself during the winter, I applied to Mr. Brackenridge, who, on the 28th of January last (1874), secured a very perfect specimen of the aërial portion or chimney of one of the nests having the orifice closed in the way above described, and most kindly transmitted it to me.
[147] P. A. Latreille, Mem. Soc. Hist. Nat., Paris (an. VII. de la République), p. 124: "L'araignée tarentule ferme aussi son habitation, mais cet opercule n'est pas mobile, et n'est construit que pour l'hiver."
I have, on a very few occasions, found the doors of a wafer or cork nest spun up during the winter at Mentone, and on digging have discovered the spider alive, though partially torpid, inside; but this is quite an exceptional event. I should much like to know, however, whether this becomes the rule in the case of the nests of those trap-door spiders which inhabit climates less favoured than that of Mentone.
In my concluding remarks in Ants and Spiders I called attention to the importance which attaches to a knowledge of the food and manner of feeding of any creature whose life-history we may wish to study, and I would now once more press the subject on the attention of my readers. For the range and distribution of a species largely depends upon the nature of its food, and this will also be an indication of the rivals with which it has to compete in the struggle for existence; the times and seasons of its activity, and in many cases even the structure and position of its dwelling-place will be governed by this same all-important question of food-supply.
I have now detected the remains of insects, and of ants especially, in the nest of every species of trap-door spider which I have examined in situ; very frequently, however, one may open several nests in succession without finding any of these débris, and at other times they will only be detected beneath the existing bottom of the tube, layers of silk having been spun over successive layers of refuse.
The horny coats of ants form by very far the largest proportion of these remains, and I have lately been much struck by the number of instances in which, while digging out ants' nests at Mentone, I have found trap-door nests (especially those of N. Manderstjernæ and N. Moggridgii) in their midst, the tubes often traversing the very heart of the ants' colony and coming into close contact with the galleries and chambers of the ants. The doors in these instances had almost always escaped my notice, and, indeed, they so closely resembled the surface of the ground that even when I knew, from having accidentally cut across the tube below ground, that one of these doors must lie near a given spot, yet I could only discover it by following the passage from below upwards. This perfect concealment is doubtless of essential importance to the spiders' success in life, for, if they once alarmed the whole colony of ants and let them know the exact whereabouts of their lurking-place, they would soon learn to avoid it.
But, as it is, the work of opening the door, snatching in an ant, and closing it again, is but the affair of a second or two, and before the companions of the victim have time to realize the nature of the phenomenon, the gaping earth has closed again and become once more, to all appearance, part of the solid and trustworthy ground.