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.]
Again, Mr. F. Pollock[87] relates of the young of _Epeira aurelia_,
which he observed in Madeira, that when seven weeks old they made a
web the size of a penny, and that these nets have the same beautiful
symmetry as those of the full-grown spider. Those of the latter are
vertical, circular, made of about 250 feet of thread, having about
35 radial lines and 38 concentric circles, the outermost of which
is some 20 inches in diameter. After the lapse of a day or two the
web loses its adhesive property and a new one is made. In about six
months the female _Epeira_ has completed her ten changes of skin, one
of which takes place in the cocoon, and "at the end of eight months
the spider is 2700 times as heavy as at its birth." This _Epeira_
lives, we are told, for about eighteen months.
[Footnote 87: The History and Habits of _Epeira aurelia_, in Annals
and Mag of Nat. Hist. for June, 1865.]
One can scarcely contemplate the work of these architects and
weavers, and especially of the trap-door makers, without being
carried away into the whirlpool of discussion which has so long raged
round the word _instinct_.
Do the young spiders build their first nest by instinct--that is to
say, independently of all teaching or personal experience--or do they
copy the nests in which they were hatched?
What is wanting, however, is not discussion, of which we have had
enough, but demonstration, and demonstration is hard to come by,
depending as it must upon careful and repeated experiment.
If it were practicable, and I have no reason to know that it is not,
to rear spiders from the egg away from the nest, and then to cause
them to build in places where they should be perfectly at home and
yet cut off from all communication with their kind, we might hope to
learn whether they can construct the characteristic nests of their
species without ever having seen one.
Mr. Wallace[88] shows that there is some reason to doubt whether
birds, which are so frequently said to build by instinct, would,
under parallel circumstances, construct the nest proper to their
kind; and he states that birds brought up from the egg in cages do
not do so, nor do they even sing their parents' song without being
taught.
[Footnote 88: Chapters on Instinct and on the Philosophy of Birds'
Nests, in his Contributions to the Theory of Natural Selection.]
Of course we can scarcely compare birds and spiders together, but we
should hesitate, in view of Mr. Wallace's expressed opinion as to the
nest-building habits of the former, to assume that the latter are
independent of teaching and personal experience. It may very possibly
be so, but it has never been proved.
I have endeavoured to gather together all the published records
of the nests of spiders belonging to the sub-order _Territelariæ_,
with a view, if possible, to trace out the geographical range of the
several types of structure. I have, however, met with but a small
amount of success, and even among the limited number of tolerably
complete accounts of nests which I have been able to discover,
several made no mention of the spider to which the nest belongs.
Prof. Ausserer[89] has enumerated 215 species of _Territelariæ_ as
having been found in the world at large, but of this large number
ten only, as far as I have been able to learn, have been described
in connexion with their nests, and eight of these belong to the
Mediterranean region.[90] To these we may now add two more, namely,
_Nemesia meridionalis_, with its branched double-door nest, and _N.
Eleanora_ the builder of the unbranched double-door nest, thus making
twelve in all.
[Footnote 89: In his monograph of _Territelariæ_ quoted above.]
[Footnote 90: I use this term in its widest sense, making it even
include Morocco. A list of the species known to inhabit this region
will be found in Appendix C.]
Three of the twelve, however, _Atypus piceus_, _A. Blackwallii_, and
_Nemesia cellicola_,[91] do not appear to build true trap-doors, but
only a simple silk tube without any covering at the mouth.
[Footnote 91: See Appendix A, p. 141.]
The following tabular view will show to which of the four types of
trap-door nest those of the remaining nine spiders belong, and their
geographical distribution:--
TRAP-DOOR SPIDERS WHICH BUILD
Nests of the cork type.
_Idiops syriacus_, Beirût.
_Cteniza fodiens (Ct. Sauvagei)_, Corsica, Pisa, Mentone.
_Ct. ædificatoria_, Tangiers.
_Ct. (Cyrtocarenum) ionicum_, Ionian Islands.
_Ct. (Cyrtocarenum) Ariana_, Naxos, Tinos.
_Nemesia cæmentaria_, South of France, Spain, Sardinia, Corsica,
Sicily, Algiers, and the var. _germanica_ from Wippach, near
Görz.
[Nests, apparently of the true cork type, have also been found in
Australia, New Granada, India, and the island of Formosa, but their
occupants are unknown.]
Nests of the single-door wafer type.
_Cteniza nidulans_, West Indies (and South America?)
Nests of the double-door branched type.
_Nemesia meridionalis_, Mentone, Cannes, and Sestri, near Genoa.
Nests of the double-door unbranched type.
_Nemesia Eleanora_, Mentone, and Cannes.
As far, therefore, as I know at present, the cork type of nest is the
only one which is widely spread, and which is constructed by spiders
of more than one species. For, while the single-door wafer, and the
branched and unbranched double-door nests are each the work of one
particular spider, we see that nests of the cork type are made by
spiders of six distinct species, belonging to at least three genera.
It is almost certain that a much larger number of spiders of
different kinds, though all probably members of the sub-order
_Territelariæ_, construct nests of the cork type, for descriptions
and specimens of trap-doors of this kind are brought from the most
distant parts of the globe. It is true that these specimens and
descriptions usually only show us the surface-door, but as far as our
present knowledge goes, we are led to suppose that a door of the
cork type is always associated with a simple tube, in which there is
no trace of a second door or valve, so that, judging of the unknown
by the known, we conclude that nests which possess the characteristic
peculiarity of a true cork door are true cork nests in other respects
also. Further research may possibly show that there are exceptions to
this generalization, but I do not at present know of any.
I have seen Australian specimens of large trap-doors, of the cork
type, measuring from one to two inches across. In some of these the
doors were scarcely more than semicircular but very thick, and having
their edges bevelled so as to correspond with the sloping margin of
the tube;[92] in others, found at Paramatta, and described to me by
Lady Parker as being tenanted by a black spider, the doors were said
to be circular and much smaller, scarcely larger than a sixpence, and
of the cork type.
[Footnote 92: Specimens of Australian nests may be seen in the cases
at the British Museum.]
The upper portion of a nest from New Granada has been figured and
described by M. Victor Audouin,[93] which closely resembles that
drawn at Fig. A in Plate VII., p. 88, but the door is about a third
larger.
[Footnote 93: Note sur la demeure d'une araignée maçonne de
l'Amérique du Sud. Annales des Sciences Naturelles (Zoologie), tom.
vii. tab. 3, p. 227-231.]
I have also been assured that nests of the cork type are found in
many parts of India, and we have seen above that they are reported to
be common in the island of Formosa.
Putting all this together, it will be seen that nests of this type
are found all round the globe; in Formosa, India, Syria, the Grecian
Archipelago, Italy, and the adjacent islands, Trieste, South France,
Spain, Morocco, New Granada, and Australia; while the single-door
wafer nest is only known at present in the West India islands;[94]
the branched double-door nest at Mentone, Cannes, and Pegli near
Genoa, and [doubtfully] near Naples and in Ischia; and the unbranched
double-door type at Mentone and Cannes alone. It is quite probable
that these three latter forms of nest will some day be found to
have a much wider range than that assigned to them here, but I can
scarcely think it likely that they will ever be shown to claim the
world-wide distribution of the cork type. Supposing that these nests
are eventually discovered in many widely distant localities, a very
interesting question will arise as to the specific characters of
the spiders which inhabit and construct them. Shall we then find,
for example, that nests of the unbranched double-door type are not
tenanted and fabricated by _Nemesia Eleanora_ alone, as we have
hitherto found to be the case, but by many other distinct species
also, each in its peculiar district?
[Footnote 94: There is a nest exhibited in the Museum collection at
the Jardin des Plantes at Paris, marked "Amérique du Sud," which is
perhaps of this type.]
That is to say, will the type of nest remain the same while the
occupants vary, as in the cork nests?
If, on the other hand, we learn that these three types, the
single-door wafer, the branched and unbranched double-door nests, are
very local, we shall be led to inquire into the probable causes of
this limitation.
But we must study much more closely the habits of these trap-door
spiders, and the difficulties and dangers to which they are exposed,
if we wish to appreciate fully the true meaning and intention of
the structure of their nests, and to find the clue to the difficult
question why one type should be more frequently adopted than another.
Above all, we must discover what are their enemies, and how and when
they are most exposed to them. M. de Walckenaer gives an entertaining
account[95] of the enemies to which spiders generally are exposed,
and of this the following list is an abstract.
[Footnote 95: Histoire des Insectes Aptères (Suites à Buffon), vol.
i. p. 172-7.]
Many kinds of monkeys, squirrels, and several sorts of birds, as
well as lizards, tortoises, frogs, and toads prey upon spiders. A
species of black sheep, found in the steppes of Asiatic Russia,
unearths the tarantulas (Lycosa), and eats them. ("Une espèce de
brebis noire, dans les steppes de la Russie asiatique, déterre les
tarentules et les mange"). In the East India Archipelago there
is an entire genus of birds of the passerine order, which have
been named "Arachnoptères" because the different species of which
it is composed live exclusively on spiders. Besides these, the
centipede (_Scolopendra_), and the following Hymenopterous insects,
_Philanthes_, _Sphex_, _Pompilus_, _Pimpla Ovivora_, and _P.
Arachnitor_ [which last lay their eggs in the eggs of spiders], carry
on perpetual hostilities against them.
I have seen it stated that ants are among the worst enemies of
spiders, driving their galleries through the silk tubes of the latter
and devouring their eggs. Of this I have never seen any trace, and,
on the contrary, have on four occasions found the remains of ants'
bodies at the bottom of the trap-door spiders' nests.
I have but seldom detected any refuse in these nests, and this
accords with what M. Erber tells us[96] of the care with which
_Cteniza Ariana_, which he watched by moonlight in the island of
Tinos, carried away the empty bodies of the beetles, the juices of
which had been sucked out, to a distance of some feet from its hole.
In October, 1872, however, I found a black layer of débris at the
bottom of five nests of _Nemesia Eleanora_, and this was composed
principally of the remains of insects, and among others of some
rather large beetles.
[Footnote 96: A translation of these very interesting observations
will be found below in Appendix B.]
As far as I am aware, M. Erber is the only naturalist who has ever
placed any detailed observations on record as to the nocturnal habits
of a trap-door spider in its native haunts; and we may learn from
him how we should watch these creatures, if we wish to discover the
manner in which they take their prey, and of what their prey consists.
He relates how he witnessed the capture, in the long low snare
which _Cteniza Ariana_ spreads close to the ground, of two strong,
night-flying beetles (_Pimelia_ and _Cephalostenus_), and how these
were at once devoured, and their horny coats thrown away.
More observations of this kind are greatly wanted, as it is most
important that we should know what are the principal sources of food
upon which these spiders depend for their existence.
If we could answer the questions, what do they eat? and what do they
fear? we should have advanced a long way towards resolving the larger
problem as to the causes which limit particular species to certain
districts.
I greatly envy those who are able to travel, and who have it in their
power to investigate the habits of these creatures at several widely
separated points; for there seems every probability that other new
types of nest remain to be detected in warm climates, some of which
may perhaps exceed those we have been here studying in beauty of
workmanship and adaptation; it is at least certain that an abundant
harvest of interesting facts in the life history of trap-door spiders
remains yet to be gathered in.
Indeed it appears to me that we are only on the threshold of
discoveries of this kind, and that the materials brought together in
the preceding pages may be considered as but a small sample of what
may be collected on the outermost edge of this great domain.
I shall be satisfied if I have been able in the present little work,
to hold the door sufficiently ajar to permit those who love nature
and her ways to catch a glimpse of the wonders and beauties of the
untrodden land that lies beyond.
APPENDIX.
A.
_Nemesia (Mygale) meridionalis_, Costa.[97]
[Footnote 97: Costa, Fauna del Regno di Napoli, Aracnidi (1861), p.
14, tab. i. figs. 1-4. [Translation.]]
"M. fusco rufoque-flavicante, maculis obscurioribus, thorace
radiatim, abdomine seriatim dispositis, subtus thorace rufescente,
abdomine flavidulo, mandibulis spinarum serie unica, tarsis omnibus
spinulosis."
"The cephalothorax oval, elongated and truncate in front, while the
head is smooth and bare, with a group of eight eyes, a little keeled
in the middle; of a fulvous-brown colour, with ten rather dusky
spots arranged in rays, and corresponding to the direction of the
eight legs (anche) and the two maxillæ. The mandibles are large,
horizontal at first, then curved downwards, making a quarter of a
circle, furnished with numerous hairs, especially on the inner side,
and at the anterior extremity above there are mobile and rather long
spines; below they are channelled, with six little teeth or spines
on the edge (rilievo) of the inner face, clothed with many bristling
hairs, with which the outside is also covered, but without any teeth;
on the inner face they are flattened, so that they fit perfectly
close. The fang is strong, curved, acute, and black. The maxillæ
are clothed with brown hairs almost as the legs are, and at their
extremity, on the outer side, stand the long palpi, rather hairy
(pelacciuti), terminated by a very short and simple little claw.
The sternal lip is very small and round. The abdomen oval, longer
or shorter according to age, dusky ash in colour, spotted with
brown, and covered with short and depressed (rasicci) hairs. The
brown spots are disposed in slanting lines, placed obliquely to the
median line, which is also brown; below it is somewhat lighter, and
becomes slightly yellow, increasingly so in the female as pregnancy
advances. The pulmonal sacs are always pale yellow, and involved in
the fold (tramezzati dalla ripiegatura). Between these, and within
the fold itself, the female sexual organ opens, consisting of a
transverse opening invisible to the naked eye, but clearly seen on
using a lens and removing the fold under which it is concealed, by
means of the point of a scalpel or of a pin. The posterior extremity
of the anus presents four spinnerets, of which the two upper are much
the longer, and composed of four easily seen joints, the lower very
short. The feet are moderate, and the longest are of the length of
the entire body when this is fully developed (quando è perfettamente
sviluppato); of these the fourth pair are about a third longer
than the first, the third of about the same length as the second,
which is the shortest of all. The tarsi of these are armed with two
small curved claws, and the third and fourth joint with many long,
delicate, straight, and mobile spines, which in the first pair become
fewer as they approach the last joint. The eyes are arranged in three
lines, as they are represented in C, Plate I., Fig. 3, and of these
the two last of the posterior line are white and glistening, the
others brown.
"Our _Mygale_ lives in tubular cavities, or burrows, which she
excavates for herself in loose and friable soil, in walls made of
volcanic earth, in shady places, and for the most part turned to the
north or to the west, seldom to the south--hence cool and rather
damp. The burrows do not exceed the length of a palm, eight lines at
their widest part. For about the length of an inch the tube is funnel
shaped, thence it continues of a nearly uniform magnitude. Its first
direction is almost horizontal, then it rises continually, turning
to the right or left, and sometimes makes zigzags. As the tubes are
excavated in friable soil, she takes care to tapestry them inside
with the same glutinous material of which the other races make their
web, by means of which the burrows are made smooth on the inside, and
to strengthen them in such a manner that even when the outer earthy
part has become cracked, or been torn away by the action of the rain,
they remain firm and fit to conceal their inhabitant. I have often
found the tubes of web thus left exposed, as they are represented
in Plate I., Fig. 4, situated in the cement of a wall, and among
_Lycopodium denticulatum_, _Adiantum Capillus-Veneris_, _Marchantia
polymorpha_, and other small plants. And it seems that the animal,
perceiving the nature of the soil, takes care to reinforce the
silken case, so much the more as she finds the earth less firm, and
_vice versâ_. So that in burrows excavated in solid ground, with
the exception of a little space close to the aperture, the nest is
merely smoothed and daubed; while sometimes the spider constructs a
tube so strong that it supports itself even when deprived of all the
earth, the animal having had the foresight to attach it along the
course of the clefts of the rock, or to the cement of the pieces of
tufa in the wall, as represented in Plate I. They have often also a
double aperture, and the upper portions of the burrows converging,
meet and anastomose at about two inches distance. The aperture is
closed by a little door or valve (_a_), which, having its hinge in
the upper part and a little on one side, falls by its own weight, and
fits itself exactly to the opening. The outer surface of the wicket
is covered with earth, cemented by the glue of the spider, so that
it is rendered imperceptible to common eyes, and the industrious
little creature takes care to leave around the aperture a kind of
rim, to which the door fitting closely, leaves no passage for any
animal, nor does it show its edges. At the bottom of its tube the
creature keeps her numerous offspring, and always stands herself as
sentinel at the door, holding the wicket raised by means of the four
anterior feet, and the palpi, curved extremities of which she inserts
between the rim of the tube and of the door, as represented in _a'
f_. Sometimes, however, they do not appear, but she leaves only the
chink for observation, as one sees in _a_ of the same figure. Fig.
2, at _c_, represents the aperture of an abandoned burrow, and at
_d_ the raised door of another burrow, with its almost funnel-shaped
aperture. That which Sauvage, Olivier, and Latreille relate of her
is not true--namely, that she remains at the bottom of the burrow,
and runs to the door only when she sees it threatened, in order to
keep the door firmly closed. On the contrary, always standing at the
door as sentinel, she leaves it as soon as she thinks it in danger,
so that it can be raised without the least effort: but if you hold
it a little raised without making any sign of movement, she turns
on her back, and comes out to draw it down with her feet, making
all the efforts she can to conquer the obstacle. But if you take
it away entirely, she turns down the edges to close the aperture
as best she can, and that she does hurriedly, without waiting for
night. The light seems to offend her so much that, if exposed to the
full day, she remains so stupefied as to appear dead, nor does she
move even if shaken; on the contrary, she constantly stops still and
holds herself with her feet pressed against her body. At last, if
very much disturbed, she runs quickly for some distance, till she
finds a place in which to hide her head, and from thence she does
not stir. I have observed that the burrows are always short when
the aperture is small, and increase in length as they augment in
diameter, which makes me conclude that it is not true that they begin
their excavations from the base of the mother's tube, where I have
never found any communication with others. This spider is found in
the neighbourhood of Naples (ne' contorni della Capitale), on the
Camaldoli, in the island of Ischia, where it lives near the sources
of mineral waters, in Gaeta at the foot of the olive trees, among the
stones in the ground, &c. &c.
"Observation. The difference which distinguishes our _Mygale_ from
the _Sauvagesii_ consists, first, in the toothing of the mandibles,
which is observable on one side only of the channel, and not on both;
secondly, in the tarsi all equally armed with spines, and not only
the four anterior ones; thirdly, in the colour of the thorax and
the abdomen, which is not uniform as is usual in the _Sauvagesii_.
Nevertheless, such differences might be in part climatic, which would
cause our _Mygale_ to be considered as a mere variety of the same
species, and the others might be the result of the different method
of examining the parts, and of the goodness of the instruments."
At p. 19, in the _Fauna del Regno di Napoli_, M. Costa gives the
following account of the nest of _Nemesia cellicola_, which he
discovered above San Martino in September, 1833:--
"Vive entro la polvere arida, nelle cavità oscure delle muraglie, e
propriamente nelle così dette _Saettiere_, ove, col glutine suo, si
costruisce un tubo delicato e mobile, che ha cura di affidare nel suo
origine a qualche corpo stabile nel fondo del muro, e che in terra
nella polvere, aprendosi l'altro estremo sul piano inclinato dalla
polvere stessa costituto."
This, with the exception of the words "e che in terra nella polvere,"
which are unintelligible to me as they stand, and appear to want a
verb, may be translated as follows:--
"She lives in the dry dust, in the obscure crevices of walls, and
especially in those which are called _Saettiere_ (loop-holed walls?),
where she constructs a delicate and flexible tube with her viscid
secretion, and which she takes care to fasten at its commencement to
some solid body at the bottom of the wall, ... the other extremity
opening on the inclined plane formed by the dust itself."
We may remark that there is here no mention of any door or
concealment at the mouth of the tube, and in this and some other
respects the nest of _Nemesia cellicola_ would appear to resemble the
nest of _Atypus piceus_ from the neighbourhood of Paris. See above in
the text, p. 78.
B.
_On the Habits of Cteniza Ariana._
The following is a free translation of an account read by M. Erber
before the Botanico Zoological Association of Vienna,[98] of the
very curious observations which he made on _Cteniza Ariana_ when
travelling in the Grecian Archipelago.
[Footnote 98: Verhand. der k. k. zoologisch-botanischer Verein in
Wien, vol. xviii. (1868), p. 905.]
"On my return voyage [from Rhodes], I stayed for a fortnight in
the island of Tinos, and, among other things, I captured several
specimens of the so-called trap-door spider (Deckelspinne) _Cteniza
Ariana_, Walck., and with much trouble procured an entire tube and
trap-door of this creature.... I am thus enabled to exhibit to this
honourable assembly the complete nest of this creature, and the
spider herself, with her eggs, preserved in alcohol, and can moreover
add some few words as to her habits.
"It needs some practice, as the specimen before you shows, to enable
one to discover the nest, as the door is always closed by day. I dug
out several of these tubes, but failed to find either the remains of
food or excrement. So there was nothing for it but to devote a couple
of nights to watch these creatures. With this view I selected a place
where many spiders had excavated their tunnels, and availed myself of
a moonlight night for my observations.
"Shortly after nine o'clock the doors opened and the spiders came
out, fastened back the trap-doors by means of threads to neighbouring
blades of grass or little stones, then spun a snare about six inches
long by half an inch high, and afterwards returned quietly to their
holes.
"I had so chosen my position that I could see three of these spiders
at the same time. I now captured a specimen and put it into spirits,
and in a short time saw entangled in the net of one of the remaining
spiders a _Pimelia_, and of the other a _Cephalostenus_, both rather
hard-lived, night-flying beetles, which were seized by the spiders,
and the latter, after sucking out the juices, carried the empty
bodies to a distance of several feet from their holes. All these
events happened in about three hours, after which time I allowed the
two spiders to remain undisturbed, and returned to the house.
"Early next morning I revisited the spot, and then perceived that
these two spiders had entirely removed the net which they made the
preceding night, but the entrance to the nest of the spider which
I had captured still remained open, and I could clearly trace the
shape of its snare, on which the heavy morning's dew lay. The upper
threads were isolated, but the snare became thicker as it approached
the ground. I found that these snares had, strange to relate, been
gathered up by the two other spiders, fastened on to the door, and
smoothly spun over, and, on making a vertical section of the doors,
which were nearly a quarter of an inch thick, I discovered that they
were composed of several layers.
"In the nests of several females I found eggs at the bottom of the
tube, not placed in cocoons, but attached by separate threads. The
young spiders when hatched are turned out from the asylum of their
mother's nest; and I found these creatures when scarcely two lines
long already established in nests three inches deep, and furnished
with perfect trap-doors, of which facts the specimens I now lay
before you are the evidence."
C.
Species of Territelariæ, enumerated by Professor Ausserer,[99]
belonging to Europe and the Mediterranean region, with synonyms, and
two species which I have added in brackets:--
[Footnote 99: Beiträge zur Kenntniss der Arachniden-Familie der
Territelariæ, in k. k. zool.-bot. Gesellschaft in Wien (1871), vol.
xxi. pp. 117-224.]
_Atypus piceus_, Sulzer. (_A. Sulzeri_, Latr.) Holland, France,
Switzerland, Germany, Northern Italy.
_A. Blackwallii_, Auss. England.
_A. Anachoreta_, L. Koch. Fiume.
_Idiops Syriacus_, Cambr. Beirût.
_Æpycephalus brevidens_, Doleschall. Sicily.
_Cteniza Sauvagei_, Rossi. (_Ct. fodiens_), Corsica, Pisa, Mentone,
Ionian Islands.
_Ct. orientalis_, Auss. Brussa.
_Ct. ædificatoria_, Westw. (_Actinopus ædificatorius_, Westw.)
Tangiers.
_Ct. algeriana_, Luc. Algiers.
_Cyrtocarenum Arianum_, Walck. (_Mygale (Cteniza) Ariana_, Walck.).
Naxos, Tinos.
_C. tigrinum_, L. Koch. Syra.
_C. grajum_, C. Koch. Nauplia in the Morea.
_C. ionicum_, Saunders. Ionia.
_C. lapidarium_, Luc. Crete.
_Cyrtauchenius Walckenaerii_, Luc. Algiers.
_C. Doleschallii_, Auss. Sicily.
_C. similis_, L. Koch. Saragossa.
_C. obscurus_, Auss. Sicily.
_Nemesia cæmentaria_, Latr. S. France, Spain, Sardinia, Corsica,
Sicily, Algiers.
_N. cæmentaria_, var. _germanica_, Auss. Wippach, near Görz in
Trieste.
[_N. meridionalis_, Costa. Naples, Ischia, Sestri near Genoa,
Mentone, and Cannes.]
[_N. Eleanora_. Mentone and Cannes.]
_N. cellicola_, Sav. et Aud. Rome, Sicily, and Egypt.
_N. maculatipes_, Doleschall. Sardinia.
_N. badia._, Auss. Corsica.
_N. manderstjernæ_, L. Koch. Nice.
_N. hispanica_, L. Koch. Madrid.
_N. macrocephala_, Auss. Palermo.
_Brachythele icterina_, C. Koch. Greece.
_B. incerta_, Auss. Brussa.
_Macrothele calpetana_, Walck. Southern Spain.
_M. luctuosa_, Luc. Southern Spain.
_Leptopelma transalpina_, Doleschall. Friuli.
_Ischnocolos triangulifer_, Doleschall. Sicily.
_I. holosericeus_, L. Koch. Spain.
_I. gracilis_, Auss. Cyprus.
_I. syriacus_, Auss. Syria.
_Chætopelma ægyptiaca_, Dol. Egypt.
D.
_Hints on Collecting Spiders._
It is very important to collect adult specimens of males and females,
but the former, from their roaming habits, are often extremely
difficult to find.
At night they may sometimes be taken by lamp-light near the nests
of the females, and certain kinds are said to live with the female
during the months of September and October. The females may usually
be found in their nests during the daytime (always in Europe?).
Large spiders should be killed, or at least stupefied with
chloroform, before being put into spirit of wine. It is convenient to
place the specimens in glass test-tubes closed with corks, and filled
with pure spirit of wine, as they may then be examined through the
glass.
When specimens of more than one species are placed in the same
tube or bottle, it is well to distinguish each by a number written
in pencil on a small strip of card fastened round the body with a
slip-noose of thread.
The patterns on the abdomen and cephalothorax of the spiders are seen
very distinctly when the spiders are immersed in spirits of wine,
and these frequently afford characters which aid in determining the
species.
M. Thorell, in the introduction to his work _On European
Spiders_,[100] gives a detailed account of a method by which
specimens may be prepared for mounting in cabinets, by drying them
within a glass tube held over a flame, but it would appear that, for
purposes of study, specimens preserved in spirit of wine are far
preferable.
[Footnote 100: Thorell (T.), On European Spiders, in Nova Acta Regiæ
Societ. Scientiar. Upsaliensis, ser. 3, vol. viii. fasc. I. et II.
(Upsala, 1871).]
It is very desirable to obtain characteristic portions of, or
if possible entire nests, but where the tubes are long, this is
extremely difficult to do satisfactorily.
Some nests, preserved in the British Museum, have been coated with
thin glue, and this appears to be of some use in binding the parts
together. I find that by stuffing the tube full of cotton-wool,
before attempting to remove the earth, the nest may sometimes be
obtained in tolerably good condition.
E.
_The Nest of the Tarantula (Lycosa Tarentula)._
As it is of some interest to compare the burrow of the Tarantula
with the nest of its near allies the trap-door spiders, I give the
following _résumé_ of M. Dufour's observations:[101]--
[Footnote 101: Quoted by M. Lucas, in his Histoire Nat. des Animaux
Crustacés et Arachnides, p. 357.]
"_Lycosa Tarentula_ forms a cylindrical burrow in the earth, often
more than a foot long, and about one inch in diameter. At about four
or five inches below the surface the perpendicular tube is bent
horizontally, and it is at this angle that the Tarantula watches for
the approach of enemies or prey.
"The external orifice of the burrow of the Tarantula is ordinarily
surmounted by a separately constructed tube, and which authors have
not hitherto mentioned; this tube, a true piece of architecture,
rises to about an inch above the surface of the ground, and is
sometimes as much as two inches in diameter, being thus larger than
the burrow itself. This tube is principally composed of fragments
of wood fastened together with clayey earth, and so artistically
disposed one above the other that they form a scaffolding having
the shape of an upright column, of which the interior is a hollow
cylinder."
M. Dufour observes, however, that the exterior tube was not found in
all the nests. In every case the tube was lined with silk throughout
its whole length.
F.
The following description is that given by Prof. Ausserer in his
monograph of _Territelariæ_,[102] of a male trap-door spider
which was found at Nice, and named by Herr L. Koch _Nemesia
Manderstjernæ_. It is just possible, I think, that this male may in
reality belong to _N. meridionalis_ [Costa-Cambr.], of which the
female alone is at present known.[103] If this is the case, then the
name _Manderstjernæ_ will have to be suppressed in favour of that of
_meridionalis_. If not, we have yet to discover the female spider and
nest of another species of _Nemesia_!
[Footnote 102: Beiträge zur Kenntniss der Arachniden-Familie der
Territelariæ, in Verhand. der k. k. zool.-bot. Gesellschaft in Wien
(1871), vol. xxi. p. 170.]
[Footnote 103: Mr. Pickard-Cambridge regards this suggestion (that
_N. Manderstjernæ_ may be the male of _N. meridionalis_) not
improbable.]
5. _Nemesia Manderstjernæ_, L. Koch.
♂ Die genaue Beschreibung dieser hübschen Art ihrem Autor, Herrn
Dr. L. Koch überlassend, führen wir hier nur jene wesentlichen
Unterscheidungsmerkmale an, welche diese Species von den verwandten
auszeichnen.--Cephalothorax schön gerundet mit schmalem, mässig hohem
Kopfe.--Augenhügel hoch, nach vorn und hinten steil abfallend.--Die
vordere und hintere Augenreihe bilden 2 nahezu parallele Curven,
mit der Concavität nach vorn. Vordere Mittelaugen stehen so hoch,
dass eine Gerade von ihrer Basis zu den Seitenaugen gezogen etwas
über denselben zu stehen käme, zugleich sind sie von einander
um ihren Radius und kaum weiter von den vorderen Seitenaugen
entfernt. Augen der vorderen Reihe fast doppelt so gross als
die der hinteren.--Zähne des Rechens lang und spitz.--Palpen
mässig lang, letztes und vorletztes Glied ähnlich bewaffnet wie
bei _N. cellicola_.[104]--Bulbus birnförmig, mit etwas kurzer,
dünner Spitze.--Alle Tarsen der Beine, ebenso Metatarsus I und
II mit dünner Scopula, zugleich sind die Tarsen wehrlos.--Tibia
I keilförmig verdickt, unten an der Spitze ein starker nach
oben und innen gebogener, spitzer Zahn, vor demselben ein oben
gerade abgestutzter Höcker.--Schenkel oben und innen mit dunkelm
Längsstreifen.--Cephalothorax 6·5^{mm}.
[Footnote 104: Description of palpi of _N. cellicola_, p. 168:
"Palpen kurz, stark. Femuralglied oben bestachelt; vorletztes Glied
oben an der Spitze mit 4 starken, etwas kurzen Stacheln, auch das
Endglied nach oben mit sehr kleinen Stacheln bewaffnet. Bulbus kurz
birnförmig, in eine feine, mässiglange, fadendunne (vorn nicht
gespaltene) Spitze auslaufend."]
Nizza.
Of this description the following is, I hope, a tolerably correct
translation:--
_Nemesia Manderstjernæ_, L. Koch.
♂ Passing over the precise description of this pretty species by its
author, Herr Dr. L. Koch, let us note here some of the essential
characters which distinguish this species from its relations.
_Cephalothorax_ fairly (schön) rounded, with small, moderately
prominent head. Eye eminence (Augenhügel) prominent, steeply inclined
in front and behind. The front and rear row of eyes form two nearly
parallel curves with the concavity in front. The foremost central
eyes stand so high that a line (eine Gerade) drawn from their base to
the lateral eyes would pass just above them, although they are not
separated from the lateral eyes by a distance greater than that of
their own radius. Eyes of front row almost twice as large as those of
hind row. Teeth of rake (Rechens) long and sharp. _Palpi_ moderately
long, the last and penultimate joint armed as in _N. cellicola_.[105]
Bulb pear-shaped, with a rather shorter, more slender point. All the
tarsi of the legs, and even the metatarsi I and II, with a slender
scopula, although the tarsi are unarmed. Tibia I enlarged into a
wedge-shape, (having) beneath the apex a stout pointed tooth bent
upwards and inwards, in front of which (is) a truncated prominence
(ein oben gerade abgestutzter Höcker). Femur (Schenkel) (having)
dusky longitudinal stripes above within.--Cephalothorax 6·5^{mm}.
[Footnote 105: Description of palpi of _N. cellicola_:--_Palpi_,
short, strong. Femoral joint furnished with spines above; penultimate
joint armed with four stout rather short spines above the apex, the
terminal joint also having some very small spines. Bulb shortly
pear-shaped, running out into a fine, moderately long point, which is
slender as a thread, and not split in front.]
Nice.
G.
_On Nemesia meridionalis and N. Eleanora, Captive in Company with
their Young._
I have tried the experiment of keeping specimens of _Nemesia
meridionalis_ and _N. Eleanora_ captive in flower-pots, partly
filled with earth and covered with gauze, but I have never been
able to detect the least inclination on the part of either of these
spiders to excavate a burrow in the earth.
Thinking that I might have better success if I were to place the
mother spiders, together with their young, in captivity, I captured a
female _N. meridionalis_ and _N. Eleanora_, each with its brood, and
placed them on moist earth in flower-pots under gauze. The result,
however, was that the young spiders concealed themselves in the
crevices of the soil, while the mother spiders remained exposed.
The adult _N. meridionalis_ lived thus for twenty days (from the 7th
to the 27th of November), capturing and killing flies with which I
supplied her, but she then suddenly died.
After seventeen days' captivity the other species (_N. Eleanora_)
began to cover a small surface of the gauze with a semi-transparent
substance (which resembled varnish rather than silk), secreted from
its spinners, and four days later it began to weave a cell; this
cell took twelve days to complete, and finally assumed the shape of
a rudely-formed figure of 8, with a circular aperture at either end,
each of which was kept open during the construction of the cell, and
then closed. The gauze itself, covered with silk, formed the ceiling
of the cell, while the floor was made of silk attached to the earth,
and the sides of strong and rather opaque silk.
This cell bore no resemblance to any portion of any trap-door
nest that I have ever seen, and it is difficult to conceive how
the idea of such a structure presented itself to the spider. Its
outline indeed had some likeness to the general outline of the
spider herself, one loop of the figure 8 being rather smaller than
the other. The distance between the floor and the ceiling of this
impromptu cell was a little over half an inch, its width varying from
one inch in the broadest to eight lines in the narrowest part, while
its length was an inch and a quarter.
It would appear that the object which the spider had in view
was to construct a warm and secure retreat for the winter, and
accordingly after having completed this chamber, she no longer made
excursions to catch the flies with which I supplied her, but remained
self-immured in her cell.[106]
[Footnote 106: My observations on the captive spider were still in
progress at the time of going to print, so that the above notes must
be considered as incomplete.]
It would be interesting to discover whether any of the spiders of
this group (but which do not construct trap-door nests) pass the
winter in similar structures.
H.
_On the Structure of Cork Doors._
In order to test my theory to the effect that the trap-door nests are
enlarged from time to time, and that the numbers of layers of silk in
an undisturbed cork door should represent the number of enlargements
which the nest has undergone, I examined the doors of twenty-eight
nests of the cork type (all I believe of _N. cæmentaria_), in order
to prove whether as a rule the larger cork doors do contain more
layers of silk than the small ones, as they should on this hypothesis.
This is, I think, fairly established by the following table:--
_Comparative Table._
One cork door measuring 1 line across contained 1 layer of silk.
Four " doors " 1-1/2 lines " 3 layers "
One " door " 1-1/2 " 2 "
One " door " 1-3/4 " 4 "
One " door " 2 " 5 "
Two " doors " 2-1/2 " 6 "
One " door " 2-1/2 " 5 "
One " door " 3 " 8 "
Two " doors " 3-1/2 " 5 "
One " door " 3-1/2 " 7 "
One " door " 4 " 7 "
Two " doors " 4-1/2 " 8 "
One " door " 4-1/2 " 7 "
Two " doors " 5 " 9 "
One " door " 5 " 5 "
One " door " 5 " 6 "
One " door " 5 " 13 "
One " door " 5-1/2 " 9 "
One " door " 5-1/2 " 10 "
One " door " 5-1/2 " 14 "
One " door " 6 " 12 "
The apparent exceptions to this rule, in which the larger doors have
fewer layers than some of the smaller ones, may probably be accounted
for in the following manner.
During the heavy rains and in times of drought flakes of earth often
become detached from the sloping banks, and carry away the doors of
such nests as are found in them.
This happens frequently, and the spiders hasten to repair the damage
and spin new doors.
But I have found, on examining eight of these new doors, that, even
in large nests,[107] they do not then contain more than three layers
of silk; so that each time a nest of any size loses its door, the
number of layers is greatly reduced.
[Footnote 107: Of the eight doors in question the smallest measured
3-1/2 lines across, and the largest 7 lines.]
In the case of six of these nests I had myself acted the part of the
landslip and removed the existing door. These original and apparently
undisturbed doors measured 3-1/2, 4, 5, 5, 5, and 5 lines across, and
contained respectively 5, 7, 8, 13, 9 and 5 layers of silk; while
of the equally large doors which replaced them five contained three
layers of silk only, and the remaining nest but a single layer.
INDEX.