Chapter VII: Part II: Trap-Door Spiders (2)

When digging out these nests, after carefully removing the upper portion, I have frequently seen the lower door move across and block up the main tube in a mysterious manner, it being in reality pushed by the spider from below, and she may sometimes be captured at her post with her back set against the door. More frequently, when the spider finds that resistance is hopeless and sees the earth crumbling in, she drops to the bottom of her nest and lies there helpless, with her legs folded against her body like an embryonic creature; some, however, more savage than their neighbours, fly out and strike at the intruder with their fangs.

What then, it may be asked, is the use of the branch? I do not think that we can draw any safe conclusion from what takes place when we dig out a spider, as to what would occur if she were besieged by one of her natural enemies, such as ichneumons, sand-wasps, centipedes (_Scolopendra_), small lizards &c.[67]

[Footnote 67: For some account of the principal enemies of spiders generally, see p. 134.]

Let us suppose, however, that one of these creatures has found its way into the nest and is crawling down the tube. What will probably happen? Why, in the first place, the spider will slam the second door in the face of the intruder, and then, if worsted in the pushing match which follows, quickly draw this door back again and run up into the safety branch, when the enemy, after descending precipitately to the bottom of the main tube, will look in vain for the spider as it searches on its way up for the secret passage now closed by its trap-door. This is but a purely imaginary case, and it may be that the branch has some wholly different purpose.

It seems very improbable, however, that it should be mainly intended as a safety place for the eggs or offspring; at least if this were the case we should not expect to find it, as we do, in the nests of very young spiders (fig. B, Plate IX.), which could have no use for it.

The large spider and its nest figured at A and A 3 in Plate IX. were taken at Mentone on March 17, 1872, and the following is the technical description of the species, written by Mr. Pickard-Cambridge:--

Nemesia Meridionalis. Plate IX.

Syn. _Mygale meridionalis_ (Costa). _Fauna del Regno di Napoli_, p.
14, Pl. I., figs. 1-4, ad partem.

Female adult, length 11 to 13 lines.

This spider is very nearly allied to _N. cæmentaria_ both in
general structure and colours, but it may be distinguished by
the more elongate form both of the cephalothorax and abdomen;
the colours also of the present species are more distinctly
distributed; a well-defined narrow marginal band, irregular on
the inside, surrounds the thorax; and the caput has a large
curved patch of the same on either side of the ocular area,
with a broad tapering band tinged with orange, which runs from
immediately behind the eyes to the thoracic junction, where it
ends in a point. The transverse diameter of the ocular area is
also less in proportion to its longitudinal diameter than in _N.
cæmentaria_, and the eyes are all smaller, but placed on a similar
oval eminence, and several bristles are directed forwards from
the middle of the lower margin of the clypeus, while one or two
others are found in the ocular area, and three or four more (long,
strong, and nearly erect) form a longitudinal row along the middle
of the central tapering thoracic band. The _Falces_ are deeply
yellow-brown, with two to three elongate oval patches or short
longitudinal parallel bands on their upper sides; in their armature
the falces are similar to those of _N. cæmentaria_. The _Labium_
appeared to be less broad in proportion to its height, and the
_Sternum_ smaller and of a more oval form than in that species. The
_Abdomen_ is similarly marked, though the chocolate-brown markings
appeared to be less deep and dense, being more broken up, but still
forming several fairly defined, bold, and broad angular bars or
chevrons on the upper side. The inferior spinners, though small
(like most of the corresponding pair in species of this family),
are yet considerably stronger than in _N. cæmentaria_.

Adult females of this spider were found in tubular silk-lined
holes in the earth, closed at the external orifice with a flat
scale-like hinged lid, covered with lichens and mosses. Not quite
half way down this tube is a tubular branch running off upwards
at an angle of 45° or less; the main tube also at this point is
furnished with an elliptical-hinged valve, with which the spider
appears to have the power to close the entrance to the branch or
to shut off the upper part of the main tube. This branch (found
also in the tubes of very young examples) seems to be certainly
a strong distinguishing character in the economy of the species,
and separates it at once from _N. cæmentaria_. In the nest of _N.
meridionalis_ the tube also projects at times above the surface
of the soil upwards among the herbage which serves to conceal it.
Costa appears to have had before him this latter species as well as
what is here taken as the typical _N. meridionalis_, as he speaks
of the nests under his observation as being frequently branched,
while his description would suit both species; his figure, however,
more nearly agrees in the thoracic pattern with the spider above
described. Ausserer, in his elaborate paper on the Mygalides,
lately published (_Beiträge_ &c. vide supra), appears to have
overlooked _M. meridionalis_ (Costa) altogether; while Canestrini
and Pavesi (_Catal. degli Araneidi italiani_ in _Atti Soc. Ital.
Sc. Nat._ xi. (1869)), p. 25, include it under the synonyms of _M.
fodiens_ Walck., from which it is undoubtedly distinct, as may be
seen at once, even if it were only by the difference in the form
and structure of the lid with which the external orifice of the
tubular nest is closed.

In the case of the upper door of these branched nests, as there is but a very thin coating of earth on their upper surface, it is rare to find any of the larger mosses or lichens growing upon them; but, as if to compensate for this deficiency, a variety of foreign materials are employed which are scarcely ever found in cork doors, such as dead leaves, bits of stick, roots, straw of grasses, &c., and I have even seen freshly-cut green leaves, apparently gathered for the purpose, spun into a door which had recently been constructed.

But here again there is the widest possible difference between nest and nest in the degree of perfection in their concealment; and, although as a rule the surface of the upper door harmonizes well with the general appearance of its surroundings, there are some individual nests in which it readily catches the eye and even attracts attention.

Thus, I have seen nests in mossy banks where the doors, being made of nothing but earth and silk, showed distinctly as brown patches against the green; and those doors which are covered with earth only, even when they are surrounded by earth, are often easily detected, because when they dry up, as they quickly do, they become much paler in colour than the earth of the bank, which retains its moisture.

Perhaps in no case is the concealment more complete than when dead leaves are employed to cover the door. In some cases a single withered olive leaf only is spun in and suffices to cover the trap; in others, several are woven together with bits of wood and roots, as in the accompanying woodcut, which represents different views of the upper door of the nest which is drawn in Plate X. p. 100.

In this nest another interesting feature presents itself, for here the tube projects a short way beyond the surface of the ground and is hardened and coated with earth and fine gravel in such a way that it requires no other support. This is not commonly the case, and may perhaps be the result of a contrivance to meet the necessities of a nest which has had the surface earth washed away from it. But I have frequently observed nests in which the upper part of the tube is carried up for two or three inches through grass, moss, ferns, pellitory, or the like, the stems of the sheltering plants being interwoven with and made to support the tube.[68] In every case the second door, which is designed for resistance and requires a firm-walled tube into which it may be wedged, is below ground, and for the same reason we scarcely ever find cork nests constructed with any part of the tube projecting beyond the surface of the soil.

[Footnote 68: This aërial portion of the tube corresponds with that of _Atypus piceus_ described above (p. 78), but differs in having its aperture closed by a door.]

At fig. A, Plate XI., one of these branched nests is seen concealed in a plant of ceterach fern, and here the tube is raised a short way above the soil; while in fig. B of the same plate the common form is represented, the upper door lying flat on the surface of the ground, from which, thanks to its covering of small mosses, it is scarcely to be distinguished.

The figs. B 1 and B 2 show this door open and the lower door in its two positions.

Now that attention has been drawn to the existence of this new type of nest, I fully expect that _Nemesia meridionalis_ will be found at many points along the Riviera and in the whole Mediterranean region, but I have hitherto only discovered it at Mentone and Cannes. Mrs. Boyle saw one of these nests in the Pallavicini gardens near Genoa, and there seems every reason to believe that certain nests which have been detected near Naples and in Ischia, will, when better known, be found to be of the branched double-door type.

It seems probable that our spider belongs to the species which was first described by M. Costa,[69] under the name of _Mygale meridionalis_, though, if we are to rely implicitly on the figures and detailed account given by this naturalist, we must suppose that it constructs a different nest in Southern Italy from that which it makes on the Riviera, and one which, although it agrees in most other respects, is destitute of the characteristic subterranean door.

[Footnote 69: Fauna del Regno di Napoli, (vol. containing _Animali Articolati_, classe ii. Aracnidi: incomplete, Naples, 1861), p. 14, tab. i. figs. 1-4. See Appendix A.]

It is more likely, however, that M. Costa has overlooked the existence of the lower door, though it is strange that he should have done so, as he says that the nests "sometimes have a double aperture, and the upper portions of the burrows meet and anastomose at about two inches distance," thus showing that he was aware that the tube is branched.

One more nest only now remains to be described, and this is again an example of a new type--namely, of that which I have distinguished as the unbranched double door (Plate XII.), the work of _Nemesia Eleanora_. This nest is never branched, and its second and subterranean door is situated from one to four inches below the surface door, and only serves to close the one tube which is narrowed above the insertion of this lower door. Here, as in the branched nest, the thin and wafer-like surface door appears to serve principally for concealment and the lower one for resistance. This latter, made out of earth encased in strong white silk, is from one to two lines thick, and has, at the end away from the hinge, a similar appendage to that found in the lower door of the branched nest. This appendage serves, I imagine, as a kind of ear by which the door, when firmly jammed into the tube on the approach of an enemy, may be pulled down again as soon as the alarm is over. As in the branched nest it has the upper surface concave and the lower slightly rounded, so that when drawn back and not in use it may not obstruct the passage. The sides of this lower door slope a little, so that the crown is smaller than the base; and this is important, because it causes the door to fit more tightly when driven upwards into the tube, acting on the principle of an inverted cork door.

In form this door is somewhat elliptic, but much broader and shorter than the second door of the branched nest, and it is frequently of a nearly horse-shoe shaped outline. The second door of the branched nest is necessarily longer, having to perform the double function of closing the opening to the branch and the passage of the main tube.

In either case, however, these doors will be found to be more or less elliptic, and this is necessarily so, for, lying as they do when in use in a plane which cuts the subcylindrical tube obliquely, they have to fill a somewhat elliptical area.[70]

[Footnote 70: The lower door here, as in the branched nest (see above, p. 100), is sometimes united to the silk of the tube below by two nearly triangular gussets of silk, when, instead of being free except at the hinge, as I have represented it (Plate XII.), it is surrounded on either side by silk and only free at the extremity away from the hinge. This does not, however, alter the function of this door in any way.

It may be that these lower doors are always attached from below in this way, but it is very difficult to be sure of this, as they readily break away from the surrounding silk, when they appear quite free, as in my drawing. It was not until I adopted the plan of stuffing the tube full of cotton wool before removing the surrounding earth that I detected this fragile attachment.]

I have observed some variation as to the exact proportions of these doors, and it is quite possible that in many cases they are specially adapted to meet peculiarities in the curvature of the tube.

The nest and spider drawn at figs. A and A 3 of Plate XII. were first discovered by the Honourable Mrs. Richard Boyle at Mentone, on March 26th, 1872, and the following is the description of the species kindly prepared by Mr. Pickard-Cambridge:--

Nemesia Eleanora, sp. nov. Plate XII.

Female adult, length 11 to 12 lines.

This spider, which has (like _N. meridionalis_) probably been
confused with its near ally _N. cæmentaria_, is yet easily
distinguished from both by its deeper and richer colouring, as well
as by other characters.

The _Abdomen_ has a far more spotted appearance; in some examples
a similar series of dark, broken, slightly angular bars is
indistinctly visible on the hinder half of the upper side; in
others (the more common type) the darker colouring preponderates,
and some transverse, broken, slightly angular, or nearly curved
bars or lines of pale spots constitute the pattern; the lateral
margins of the thorax are not so distinctly yellow as in _N.
meridionalis_, and there is a single longitudinal stripe on the
caput, of a dull orange-yellow brown, commencing directly behind
the eyes and tapering to the thoracic junction; the depression
or pit at this point is more strongly marked than in either of
the two foregoing species; the ocular area is also smaller, and
its transverse diameter is less in proportion to its width; the
bristles on the margin of the clypeus, as also those within the
ocular area and in the central longitudinal line of the caput, are
similarly disposed to those in _N. meridionalis_, but are more
numerous; in some details, however, of form and structure--viz.,
the Labium and Sternum--the present species is more nearly allied
to _N. meridionalis_ than to _N. cæmentaria_. The _Legs_ seemed
to be rather longer and stronger than in either; the tarsi and
metatarsi of the two first pairs, as well as the digital joints of
the palpi, are rather densely clothed a little underneath on their
outer sides with a kind of fringe or pad of close-set hairs; in
other respects the armature of the legs appeared to be similar to
that of the other two species, except that in the present one there
are three _short strong red-brown spines in a longitudinal row on
the outer sides of the genual joints of the third pair_; these
spines were plainly visible in all the examples found, but did not
exist in any one of those of the two former species. The armature
of the falces, which are of a uniform yellow-brown colour, is
similar to that of those species.

Adult females were found in tubular silk-lined unbranched holes,
closed at the orifice with a flat scale-like hinged lid concealed
by mosses and lichens, and having a horse-shoe shaped second valve
or door less than half way down the tube, of which it serves
to shut off the upper part. In this nest, as in that of _N.
meridionalis_, the upper part of the tube often projects above the
surface of the soil.

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.

The concealment here was so complete that I should never have discovered the nest but for the merest accident. I happened to want some moss to lay with flowers in my botanical tin, and in one handful which I plucked up this trap-door lay concealed. It should be observed that the upper part of the tube and its surface door were covered with growing moss, and this moss must have lived exclusively upon the moisture which the very damp and shady situation afforded, as there was no earth mixed with the silk.

When digging out the nests of _N. Eleanora_, I have frequently seen the lower doors pushed forwards so as to close the tube; and it is my belief that the spider, after having thus barred the passage, puts her back against the door and resists in this way. I must own, however, that, though I believe I have seen the spider in this attitude when I have severed the tube from below, I am not quite certain about it.

I have twice in the months of April and May, and frequently in October and November, found young of this species in the nests with their mother. Usually they were all very small and not larger than that represented at fig. B 2, Plate IX., p. 98, but occasionally in October I have found two or three young spiders thrice the size of their companions still in the nest. On one occasion (in April) I found twenty-four small spiders clustered beneath and beside their mother.[71] I secured the whole family by quickly cutting out the mass of earth containing the lower door on the under side of which they remained crouched, and brought them home alive. I had up to this time been in the habit of killing the spiders by placing them in a stopper bottle full of strong spirit of wine, but on treating these spiders in this way I saw reason to regret having done so. I knew that these large spiders, when thrown into spirit of wine, would continue to struggle for an hour or more, spasmodically spreading out their legs as if swimming; but I had supposed that this was only muscular motion, and was not in the least aware that the unfortunate creatures were probably conscious all the while. In this instance I first placed the mother spider in the bottle, and then, after the lapse of about ten minutes, when I supposed that the spider, though still struggling, was dead to sense, I dropped in the young spiders. No sooner, however, had I done this than the mother, perceiving them, gathered all her young to her, and, after placing them beneath her, with her legs drawn up round them, as a hen screens her chickens with her wings, never stirred again, and retained this attitude until death released her, and the limbs, no longer under the control of this wonderful maternal resolution, slackened and fell abroad.[72]

[Footnote 71: I have found similar families in October and November in the nests of _N. meridionalis_, only all the young were of nearly uniform size, and very small. On November 21 I dug out a mother spider of this species (_meridionalis_) with forty-one little ones!]

[Footnote 72: My own impression is that this act was one of conscious protection on the part of the mother spider; but Mr. Pickard-Cambridge doubts this, and would attribute the action to the tendency which spiders commonly display to clutch at any material object when dying in this way.]

I need scarcely say that the small spiders were killed by the spirit in a very few instants, but it is almost certain that the mother was alive and conscious for half an hour. Now this pain can easily be spared by placing large spiders for about ten minutes in a closed box with a piece of cotton wool steeped in chloroform beside them, before dropping them into the spirit of wine, a system which I have since that day adopted and found to answer perfectly.

I examined these young spiders carefully, hoping to detect some males among them, but the males, though they differ markedly from the females when adult in their smaller size and curiously enlarged palpi, do not appear to afford any distinctive mark at this early period. It appeared that these spiders had been but recently hatched, for some among them were still semi-transparent.

I have never found young spiders in the nests of _Cteniza fodiens_ or _Nemesia cæmentaria_.

M. de Walckenaer[73] quotes a statement made by M. Rossi to the effect that _Cteniza fodiens_ carries its young on her back, as certain species of _Lycosa_ (Tarantula) do. He points out the interest which would attach to this observation if confirmed, as showing a similarity in habit between the two groups, which are otherwise nearly related.

[Footnote 73: Walckenaer (C. A. de), Les Aranéides de France (date?), p. 5.]

Observations of this kind are difficult to make satisfactorily, at least in the case of the trap-door spiders with which I am acquainted, and which appear to be nocturnal in their habits. I have certainly never seen them out of their nests in the daytime, and but rarely detected one of them (_Nemesia cæmentaria_) even venturing to peer out of her door set ajar for the purpose.[74]

[Footnote 74: M. Olivier, however, states (Encyclopédie Méthodique, tom xviii., p. 228, Art. Araignées Mineuses, Paris, 1811) that he has twice found nests in the islands off Hyères and on the promontory of St. Tropez the doors of which were set open in the daytime and the tube empty, this seeming to imply that the spiders were out hunting and were diurnal in their habits. He did not see the spiders, but from his description the nest was of the cork type.... Here is an interesting point, and one which those naturalists who make Hyères the field of their observations should endeavour to throw further light upon.]

The following very singular account is given by M. Erber[75] of the habits of _Cteniza ariana_, which he watched in the island of Tinos. I quote from the abstract given in the _Zoological Record_ cited below:--"At night these spiders come out of their nests, fasten the open trap-door to neighbouring objects, and spin a net, about six inches long by scarcely half an inch in height. In the morning the nets were removed, and Erber believes that the net of each night is added to the trap-door. He found eggs at the bottom of the tubes, attached singly to threads, to the number of about sixty. The young seem to form dwellings very early."

[Footnote 75: In Verhandlungen der k. k. zool. bot. Gesellschaft in Wien, vol. xviii. pp. 905, 906, quoted in _Zoological Record_, vol. v. p. 175 (1868); see also Appendix B.]

It would be very interesting to know whether these nocturnal habits are also found in our spiders on the Riviera.

I have been favoured[76] with a sight of an unpublished manuscript by Mr. Hansard giving an account of his observations on _Cteniza fodiens_, made in Corfu. This gentleman states that some of these spiders which he kept in captivity, used to come out at night, and might sometimes be surprised roaming about the room at a very early hour in the morning. He, however, relates that he had received from a friend an account of a trap-door spider inhabiting the island of Formosa, in the China seas, which constructed nests similar to those of _Cteniza fodiens_, but which were habitually to be seen outside their nests in the daytime, attracting attention by "staring at" any one who might approach, and then hurrying back to their nests and closing their doors after them.

[Footnote 76: I am indebted to Mr. Moseley for procuring this MS., and to Prof. Rolleston, whose property it is, for permission to make use of it.]

Lady Parker has also told me of some black trap-door spiders which were so common about Paramatta, near Sydney, in Australia, that scarcely any one paid attention to them, and which might habitually be seen out on the garden paths in the daytime near their holes, to which they would run in all haste when alarmed. The eye of the passer-by was attracted by the open doors, which were about the size of a sixpence, and fall over backwards when the spider makes her exit, but when closed, on her return, they fit so neatly that it is extremely difficult to detect them.

It will, perhaps, have been observed that I have throughout spoken of the female spider only, scarcely any allusion having been made to the male. The truth is that, though I have carefully searched for them, I have never been able to secure more than a single male spider.[77] During the winter, spring, and late autumn (October) the female appears to live solitary, in the daytime at least, and the male probably hides in the crevices of old walls and in similar places. I have diligently turned over piles of stone, greatly to the annoyance of many little scorpions, but have never secured, or even seen, another male spider. This is the more to be regretted as the species of trap-door spider are much better characterized in the male than in the female sex, the bulb-like enlargement which is found at the end of the palpi in the former taking on a great variety of forms, each of which is distinctive.

[Footnote 77: Three days before sending this MS. to print, and long after the plates had been completed, I captured on Oct. 23rd one male of _Nemesia Eleanora_. He lay crouched in a crevice in a mossy bank, and had, perhaps, been driven out of some deeper hiding-place by the heavy rains.]

M. de Walckenaer[78] says:--"C'est toujours pendant la nuit que ces aranéides travaillent à leurs habitations et courent après leur proie. C'est en Août que la Mygale maçonne (_Nemesia_--or _Mygale_--_cæmentaria_) atteint toute sa grosseur.... En Septembre elle devient mère et méchante en même temps ... les mouches, les moucherons, les petits vers lui servent de pâture; elle les prend dans les filets qu'elle étend et attache sur les inégalités des terres voisines de sa demeure. Elle vit après la ponte en société avec son mâle. Dorthès a vu plusieurs fois, dans la même habitation, le mâle et la femelle avec une trentaine de petits."

[Footnote 78: Les Aranéides de France, p. 4.]

Any one, therefore, who has an opportunity of examining the nests during the early autumn, might perhaps, discover the happy families spoken of by M. Dorthès, but which it has never been my good fortune to see. It is not known positively whether the male spider ever assists in the construction of the nest, but, as we know that the female is able to make it without his aid, there seems no reason to suppose that he does.

I have seen the female _Nemesia meridionalis_ construct a trap-door in captivity, after having been placed on a flower-pot full of earth in which I had made a cylindrical hole.[79] She quickly disappeared into this hole, and, during the night following the day of her capture, she made a thin web over the aperture, into which she wove any materials which came to hand. The trap-door at this stage resembled a rudely constructed, horizontal, geometrical web, attached by two or three threads to the earth at the mouth of the hole, while in this web were caught the bits of earth, roots, moss, leaves &c. which the spider had thrown into it from above. After the second night the door appeared nearly of the normal texture and thickness, but in no case would it open completely, and it seemed that the spider was too much disgusted with her quarters to think it worth while to make a perfect door. I believe that when a door is finished the few threads which served as supports and connected it with the earth on either side of the hinge are severed, and this is borne out by the following instance. While I was at work one evening drawing the spider's nest concealed in the plant of ceterach fern (Plate XI., fig. A, p. 105) which I had dug out for the purpose, I detected something moving at the mouth of a tiny hole [just large enough to admit a crowquill pen] in the mass of earth on the opposite side of the fern, to that in which the large trap-door lay.

[Footnote 79: An account of further experiments with captive spiders will be found in Appendix G.]

The lamp-light fell full upon it, and I soon saw that the moving object was a very small spider, not bigger than that drawn at B 2 in Plate IX., which was at work in the mouth of its tube. Whether I had, in removing this mass of earth, destroyed the door I cannot say, but it is certain that the opening of the tube was completely uncovered, and it soon became apparent that the little spider was intent upon remedying this deficiency. After a few threads had been spun from side to side of the tube I watched the spider make one or two hasty sorties, apparently spinning all the while, and finally I saw her gather up an armful, as it were, of earth and lay this on the web. After this the occupant of the tube was concealed, but I could see from the movement of the particles of earth that they were being consolidated, and that the weaving of the under surface of the door was being completed. Next morning I was able to lift up the door, which had the form of a small cup of silk, in which the earth lay. It was then soft and pliant, but in ten days time it had hardened and become a very fair specimen of a minute cork door (see figs. A 1, A 2, of Plate XI.).

On one occasion a captive _Nemesia meridionalis_ employed some pieces of scarlet braid which I had purposely strewed, along with bits of moss and fragments of leaves, in a circle round the opening of, and about two inches away from, the hole.

It is probable that these spiders have in times past learned by experience that they cannot do better than take such materials as come to hand, as these will ordinarily serve for the concealment of their door.

However, these trap-door spiders do seem to exercise some discrimination in the choice of materials; for I have observed several instances in which, when the door of a cork nest has been removed, if the door was originally covered with moss, moss will again be used in its reconstruction, even though the mouth of the tube be then surrounded by bare earth.

Thus, for example, in one case where I had cut out a little clod of mossy earth, about two inches thick and three square on the surface, containing the top of the tube and the moss-covered cork door of _N. cæmentaria_, I found, on revisiting the place six days later, that a new door had been made, and that the spider had mounted up to fetch moss from the undisturbed bank above, planting it in the earth which formed the crown of the door.[80] Here the moss actually called the eye to the trap, which lay in the little plain of brown earth made by my digging.

[Footnote 80: Mrs. Boyle first called my attention to this curious fact, of which I have since seen many examples. I have purposely removed several cork doors from mossy banks in order to observe this point.]

I have seen the same thing happen when the door of _N. Eleanora_ has been removed and replaced, moss being again used in the work of reconstruction. Trap-door spiders in warm weather very quickly replace their trap-doors; and if you pass by a wall where several nests have been robbed of their doors only a week before, they will usually be found quite perfect again.

It has been stated[81] that, if the door of a cork nest be fastened down with a pin, a second door will be found next day by the side of the former one. No doubt spiders not unfrequently find their doors blocked up by a fall of earth, and are thus obliged either to make a new opening or to prolong the old tube.

[Footnote 81: M. Dorthès on the Structure and Œconomy of some Curious Species of Aranea, in Trans. Linn. Soc. (London), II. 88-90.]

I once fastened open the surface doors of three of the double-door nests by passing a thread through the silk of the door and tying it back to some twigs above. The doors were thus turned backwards, and the aperture of the tubes, which lay in a vertical terrace wall, exposed to view.

Next day, after a night of very heavy rain, I found the doors as I had left them, but in one nest the lip of the tube had been dragged inwards so as partially to close the tube; in the second nothing appeared to have been done, but in the third nest a new covering had been very cleverly extemporized out of three fallen olive-leaves, which were loosely spun together and attached by one or two threads to the margin of the tube. This formed an admirable concealment, but did not move freely as a door, the web being too imperfect. Two days later, however, it was completed and had become a perfect door, moving on a hinge just within and below that of the former door, which still remained as I had fastened it. The other nests remained in the same condition as before, only that a little moss had been dragged into the mouth of the tube of the nest, which had been partially closed with its own lip.

The extreme reluctance which these spiders show to abandon their dwellings is curiously exemplified by what follows.

Certain nests which were furnished with two doors of the cork type were observed by Mr. S. S. Saunders[82] in the Ionian Islands. The door at the surface of these nests was normal in position and structure, but the lower one was placed at the very bottom of the nest and inverted, so that, though apparently intended to open downwards, it was permanently closed by the surrounding earth. The presence of a carefully constructed door in a situation which forbade the possibility of its ever being opened seemed, indeed, something difficult to account for. However, it occurred to Mr. Saunders that, as these nests were found in the cultivated ground round the roots of olive-trees, they may occasionally have got turned topsy-turvy when the soil was broken up. The spider then, finding her door buried below in the ground and the bottom of the tube at the surface, would have either to seek new quarters or to adapt the nest to its altered position, and make an opening and door at the exposed end. In order to try whether one of these spiders would do this Mr. Saunders placed a nest, with its occupant inside, upside down in a flower-pot. After the lapse of ten days a new door was made, exactly as he had conjectured it would be, and the nest presented two doors like those which he had found at first.

[Footnote 82: Description of a species of Mygale from Ionia in Trans. of Ent. Soc. (London, 1839), III. p. 160.]

There is a specimen of one of these inverted nests, with its two doors, in the British Museum, and this might easily be supposed, at first sight, to be an example of a new kind of double-door nest. On close inspection, however, it will be seen that one of the two doors is discoloured and partly decayed, this being, no doubt, the one which had been buried beneath in the earth and so rendered useless.

Questions have often been asked as to the manner in which trap-door nests are commenced in the first instance, and whether the weaving of the silk lining is begun at the top or the bottom of the tube.

The structure of the cork door also, which often appears so perfectly turned as to resemble the work of a potter's lathe, is another difficulty.

These questions have, as it seems to me, been needlessly complicated by taking it for granted that the perfect nest of the mature spider is made all at one time, that the tube, perhaps of a foot in length, is excavated, lined, and furnished with a door within some short period of time, such as ten days or a fortnight, perhaps.

On the contrary, I believe that the nests are, as a rule, the result of many successive enlargements, and that the nest of the infant, the tube of which is no bigger than a crowquill, is not abandoned, but becomes that of the full-grown spider. This must require time, but how long, whether months or years, we have yet to learn.

Very little is known at present as to the longevity of spiders, but Mr. Blackwall[83] says that some live only one year, while others, such as _Tegenaria civilis_ and _Segestria senoculata_, have been known to live four.

[Footnote 83: Spiders of Great Britain and Ireland, p. 8.]

Whether the trap-door spiders are very long lived or not I cannot positively say, but, from the appearance of the growth of moss and lichen on the doors of some nests which I have observed, I am inclined to think that they must have been inhabited for more than a twelvemonth.

Evidence of the enlargement of the door is not very rare to meet with, though, as a rule, the new piece is woven on to the old with such neatness as more or less to obscure this. In fig. B, Plate X., p. 100, the old and smaller surface-door of a nest of _Nemesia meridionalis_ is seen partially attached to the larger new door, which has been constructed below it; while in fig. C of the same plate, three doors, or rather three enlargements of one door, may be traced. It is this, I believe, that gives rise to the tiled appearance which these trap-doors sometimes present, and which has caused them to be compared to oyster-shells. Something similar may also be occasionally seen in doors of the cork type, as, for example, in that figured at A and A 1 in Plate VIII., p. 94, where the old and smaller door is seen partially raised above the surface of the new one. This I imagine to be merely an example of rather clumsy workmanship, as, if I am right, a full-sized cork door usually incloses within itself several lesser doors, which formerly fitted the tube and have had to be enlarged.

This is borne out by the fact that such a door will, on examination, be found to consist of several layers of silk, with more or less earth between each, these layers decreasing in size from without inwards, and together forming a sort of saucer in which the small central mass of earth lies. Thus by moistening a series of the cork doors of _Nemesia cæmentaria_, I have been able to detach, in one of medium size, from six to fourteen circular patches of silk, of which the outermost, or that which forms the lower surface of the door, is the largest, and the innermost the smallest, the others being intermediate in size as in position. Perhaps if I had had larger doors at my disposal for examination I might have found more layers, as other authors[84] speak of a much greater number of layers in the cork doors of _Cteniza fodiens_. Be this as it may, I am confirmed in my opinion that the layers of silk mark the successive enlargements of the nest by the additional fact that in very small doors the layers of silk are few or single, and that a proportion is observable as a rule between the size of the door and the number of layers of which it is composed.[85]

[Footnote 84: M. de Walckenaer seems to have found more than thirty alternate layers of silk and earth in one of the doors of _Cteniza fodiens_, as we may gather from the following:--"Quoique cette porte n'ait guère que trois lignes d'epaisseur, elle est formée par la superposition de plus de trente couches de terre séparées les unes des autres par autant de couches de toile. Toutes ces assises successives s'emboitent les unes dans les autres comme les poids de cuivre à l'usage de nos petites balances. Les couches de toile se terminent au pourtour de la porte." Walckenaer, Histoire des Insectes Aptères (Suites à Buffon), vol. i. p. 238 (Paris, 1837).

I have not found the regular layers of earth and silk of which M. de Walckenaer speaks, the silk layers being usually in contact at their centres and only separated by a little ring of earth interposed between their edges, this earth being thickest towards the circumference of the layers of silk.]

[Footnote 85: This may be seen by the comparison of the composition of doors of different sizes, given in Appendix H.]

Another proof that enlargement takes place, may at times be found in the nests of _N. Eleanora_, where one, or even two useless doors may be detected behind the lower door.

Now when there are three lower doors in this way the one which is in use is the largest, and the door lying nearest to this one the next in size, while the hindmost is the smallest of all. But though those abandoned doors are now too small to fit the existing tube, they did so, no doubt, in their day, for they are exact copies in miniature of the ordinary horse-shoe shaped lower doors. The lower door actually in use may sometimes be found to have two separable cases of thick silk enclosing the central mass of earth, and this also, very probably, represents enlargement. In the nests of _N. meridionalis_ I have never found any of these abandoned doors behind the one in use, nor should I expect to find any, for if they were present they would permanently obstruct the entrance from the main tube to the branch.

It is clear that it is better economy on the part of the spider to enlarge its nest rather than build a new one each time. If we compare the infant spider and its nest (fig. B, Plate IX., p. 98) with the full-grown creature and its nest (fig. A, Plate IX.), it becomes evident that the growing spider must either construct many nests of intermediate size, or frequently enlarge the original domicile. And we do in fact find nests of all sizes between the two extremes.

I cannot help thinking that these very small nests, built as they are by minute spiders probably not very long hatched from the egg, must rank among the most marvellous structures of the kind with which we are acquainted. That so young and weak a creature should be able to excavate a tube in the earth many times its own length, and know how to make a perfect miniature of the nest of its parents, seems to be a fact which has scarcely a parallel in nature.

When we remember how difficult a thing it is for even a trained draughtsman to reduce by eye a complicated drawing or model to a greatly diminished scale, we must own that the performance of this feat 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.

It seems to be the rule with spiders generally that the offspring should leave the nest and construct dwellings for themselves when very young.

Mr. Blackwall,[86] speaking of British spiders, says:--"Complicated as the processes are by which these symmetrical nets are produced, nevertheless young spiders, acting under the influence of instinctive impulse, display, even in their first attempts to fabricate them, as consummate skill as the most experienced individuals."

[Footnote 86: Loc. cit., p. 11.]