TRAP-DOOR SPIDERS.
It is now one hundred and sixteen years since Patrick Browne gave an
illustration in his _Civil and Natural History of Jamaica_[43] of the
nest of a trap-door spider, the first record of the kind with which
I am acquainted. Seven years later the careful observations of the
Abbé Sauvages appeared,[44] in which he gave a very good description
of the nests of the "araignée maçonne" (_Nemesia cæmentaria_), which
he discovered near Montpellier, likening them to little rabbit
burrows lined with silk and closed by a tightly-fitting moveable
door. In 1778 and 1794 Rossi[45] published an interesting account of
the nest and habits of a trap-door spider which he had observed in
Corsica and near Pisa; and from that time up to the present day the
curious dwellings of these creatures, many species of which have been
discovered in warm climates, have continued to attract the attention
of naturalists.
[Footnote 43: P. 420, tab. 44, fig. 3 a. This work was published in
London in 1756.]
[Footnote 44: In Histoire de l'Acad. Royale des Sciences (Paris
1763), p. 26-30.]
[Footnote 45: Rossi (P.), Osservazione Insettologische (Memorie di
Matematica e Fisica della Società Italiana, vol. iv. (1778), and
Fauna Etrusca, vol. ii. (1794)).]
Very little, however, has been added to our knowledge of the
life-history of these remarkable architects for several years past,
and, indeed, I think it may be safely asserted that the study of the
habits and interdependence of the members of the animate world has
not, during the last fifty years, made anything like a corresponding
progress to that which may be seen in classification and description.
The microscope has led many who, a century ago, would have found
their chief delight in observing those points in the habits and
external characters of living creatures which the naked eye could
readily seize upon, to look much closer, to anatomize and describe in
detail every organism, great and small, and to examine every tissue
and cell.
It is, however, to the materials now being amassed by these modern
"cabinet naturalists" that recourse must be had if we wish to form
a true comprehension of the functions and habits of living things.
They must tell us, for example, what instruments, tactile and visual,
an animal possesses if we wish to understand how it constructs a
particular fabric, so that the "field naturalist" will have to apply
to his brother of the "cabinet" before he can turn his observations
to good account.
Still, the fact remains that the habits of plants and animals afford
many openings for careful investigation, and such as are especially
within the reach of those lovers of nature who have ample time at
their disposal, and the opportunity to spend it in a warm climate
where life abounds, and is never wholly checked even in the depth of
winter. It seems strange to think that collectors so frequently take
creatures out of wonderfully constructed nests and yet never observe,
or at any rate never describe, the structure of these fabrics.
Thus, for example, the dwellings of only eight out of the thirty-six
species of trap-door spider stated by Prof. Ausserer[46] to belong to
the Mediterranean region are known in books, those of the remaining
twenty-eight being, as far as I have been able to learn, yet to be
discovered. This is the more strange as from the nocturnal habits
of these creatures it is almost always necessary to dig them out
of their nests; indeed it is more than probable that if all the
dwellings which have been destroyed had been described, the following
pages would never have appeared.
[Footnote 46: Prof. Ausserer (Anton.), Beiträge zur Kenntniss der
Arachniden Familie der Territelariæ (Mygalidæ), in Verhandlungen der
k.k. Zool. Bot. Gesellschaft in Wien. Jahrg. 1871, Band xxi.]
Before proceeding to pass briefly in review what has been written on
the subject of trap-door spiders, it will be well to take one glance
at the relation which these spiders bear to their fellows. The great
order of spiders (_Araneæ_) has recently[47] been divided into seven
sub-orders, the fourth of which, _Territelariæ_, includes all the
trap-door spiders, and some others which do not construct trap-doors.
This sub-order corresponds with that which was formerly called
_Mygalidæ_, but this name, as well as that of _Mygale_, originally
given to all trap-door spiders, has been abandoned because this
latter name had previously been applied to a genus of Mammals, and it
was feared that confusion might arise.
[Footnote 47: Thorell, On European Spiders, in Nova Acta Reg. Soc.
Scient. Upsaliensis, ser. iii. vol. vii. fasc. 1 and 2 (1869-70).]
The _Territelariæ_ [or underground weavers] are distinguished from
all other spiders by the position of their falces,[48] which have
the fang directed downwards, and move vertically parallel to one
another. Thus when a victim is seized by one of the _Territelariæ_
it receives a downward blow, while other spiders strike sideways,
the falces moving in a horizontal or oblique direction. With very
few exceptions this sub-order may also be known by the presence of
four blotches of paler colour at the base of the abdomen underneath,
indicating the position of four air-sacs, almost all, or indeed
perhaps all, other spiders having but two.
[Footnote 48: Sometimes called mandibles. One of these is
represented, enlarged, at Fig. A 7. in Plate VII., p. 88.]
Certain species of _Territelariæ_ are the only spiders known to
construct nests closed with a door, and these creatures must be
admitted to rank among the first of Nature's handicraftsmen and
inventors.
The geometrical webs of many common spiders are very beautiful
structures, but these are for the most part only snares for prey, and
not permanent dwellings, although the cocoons in which the eggs are
placed are often most ingeniously contrived. Thus in the south we
may sometimes find an inverted balloon of strong silk about an inch
long attached to heath and other bushes, which, if examined during
the winter, will be found to contain in its centre a case enclosing
a mass of eggs about one-third the bulk of the entire cocoon.
This inner case is shaped exactly like the outer, and both have a
circular silk lid carefully closed, and the space between the two is
filled with a dense mass of golden-brown silk, which acts no doubt
as an excellent non-conductor. This cocoon is the work of _Epeira
fasciata_, a species apparently only found in southern Europe.
Other spiders again, such as _Theridion_,[49] suspend by a long
and delicate cord of silk a minute balloon, scarcely larger than
a seed-pearl, containing their eggs, which sways to and fro in
the lightest breath of air. But admirable as these cocoons and
geometrical snares are, the homes of these and of spiders generally
do not exhibit much contrivance or ingenuity, or cannot at any rate
be ranked in the same category as those of the trap-door spider. But
it may be asked, why should we admire the one more than the other,
since it is clear that the most squalid and mean-looking nest exactly
serves the purpose of its occupant, whether for shelter or defence,
and in many cases a spider might even say with truth that as for her
home it would not be so safe if it were not so dirty.
[Footnote 49: _Theridion variegatum_ (Bl.). _Ero tuberculata_, Koch.]
But the answer is simple: the trap-door spider's dwelling is to that
of common spiders what the Mont Cenis tunnel is to other tunnels, and
something besides.
What delights us is to see how by clever contrivance and great
perseverance new and multiplied difficulties have been overcome, and
dangers avoided, and the interest aroused is exactly proportionate to
the amount of these difficulties and dangers.
It is hoped that the following pages and their accompanying
illustrations will vindicate the claims of these spiders to the
marked attention and admiration which is here asserted to be their
due as architects and engineers.
There is but one British or North European representative of the
_Territelariæ_--namely, _Atypus piceus_ (or _Sulzeri_),[50] and this
creature does not appear to deserve the name of trap-door spider,
for in three nests which M. H. Lucas kindly showed me, preserved at
the Jardin des Plantes at Paris, the mouth of the tube was destitute
of any covering. I gathered from what I saw, and from what M. Lucas
told me, that these nests [which he had taken in the neighbourhood
of Paris], consist of a silk tube from eight to ten inches long,
of which about one inch only at the lower extremity penetrates the
earth, the remainder being carried upwards in an irregular and
sinuous course among the stems and leaves of small plants and grasses
to which it is attached. When the tube is removed from these supports
it collapses, and appears like a rather coarsely woven ribbon-shaped
strip of silk.[51]
[Footnote 50: Unless it should prove, as Prof. Ausserer suggests,
that the British _Atypus_ is distinct from the Continental, when it
would bear the name of _Atypus Blackwallii_. (Ausserer, l. c. p. 17).]
[Footnote 51: I have never been able to meet with an English specimen
of the nest of _Atypus_; but it would appear from the descriptions
that the English differ from the French nests in being subterranean,
and in having the mouth of the tube concealed by a loose flap of
silk. Mr. Blackwall says: [Spiders of Great Britain and Ireland, part
i. p. 14] "Dr. Leech has taken specimens of _Atypus Sulzeri_ in the
vicinity of London and Exeter. It excavates, in humid situations, a
subterraneous gallery, which is at first horizontal, but inclines
downwards towards its termination. In this gallery it spins a tube
of white silk, of a compact texture, about half inch in diameter....
Part of the tube hangs outside of the aperture to protect the
entrance."
It would be interesting to learn whether these differences
permanently distinguish the English from the French nests, and if so,
whether the spiders which construct them are not, as Prof. Ausserer
is inclined to believe, distinct also.]
Four types of trap-door nest, properly so called, may now be
distinguished in the world at large, and these are represented
diagrammatically in the following woodcut.[52]
[Footnote 52: Where all the figures, except C 1, and D 1, which are
of the natural size, are reduced to about one-third of the actual
size in large specimens.]
Of these two only (A and B) were known up to the present time, the
construction of which is much simpler than that of the two new types
(C and D), which I have hitherto only found at Mentone and Cannes.[53]
[Footnote 53: It must not be supposed that I have a sole or prior
claim to what may prove to be new and of interest in the following
observations on the Trap-door Spiders of the Riviera. This priority
belongs to the Hon. Mrs. Richard Boyle, to whom I owe it that I ever
took up the subject. It was, thanks to her guidance, that I first
became acquainted with these marvellously-concealed nests in their
native haunts, and to her active help that I finally arrived at a
comprehension of the different types of structure which they present.]
[Illustration]
It will be seen at a glance that A and B have but one door, while C
and D have two, these latter having a surface door, and also another
door a short way under ground.
All the nests consist of a tube excavated in the earth to a greater
or less depth, unbranched in all but D, and in every case lined with
silk, this lining being continuous with the lining of the door or
doors of which it forms the hinge.
I have found it convenient to distinguish these four types of nests
by the following names:--A, the single door cork nest, or shortly
the cork nest; B, the single door wafer nest; C, the double door
unbranched nest; and D, the double door branched nest.
The type B has only been found in the West India Islands, and is
chiefly distinguished from A by having a thin and wafer-like door,
wholly constructed of silk, without admixture of earth, lying on
rather than fitting into the aperture of the tube; while in A
the door is much thicker, made of layers of earth and silk, and
so contrived that it tightly closes the mouth of the tube, which
is bevelled to receive it, much as a cork closes the neck of a
bottle.[54]
[Footnote 54: Nests belonging to the type A, are represented in
Plates VII., p. 88, and VIII., p. 94.]
The West Indian nests are of a much tougher and coarser texture than
those which I have seen in Europe, and vary somewhat in the shape of
their tube, which is curved or straight, and sometimes has near its
lower extremity a short spur-shaped enlargement, giving to the whole
a ludicrous resemblance to a stocking, of which this spur is the heel.
Mr. Gosse,[55] in his _Naturalist's Sojourn in Jamaica_, has given
an admirable description of one of these single door wafer nests, the
work of _Cteniza nidulans_, which I cannot do better than quote:--
[Footnote 55: Gosse (P. H.), Naturalist's Sojourn in Jamaica (1851),
p. 115-118. See also for another description of the same nest
Latreille's Vues Générales sur les Araneides, in the Nouv. Ann. du
Muséum (Paris, 1832), tom. i. p. 73-4.]
The nest is "cylindrical, or nearly so, from four to ten inches deep,
and about one inch in diameter; the bottom is rounded; and the top,
which is at the surface of the soil, is closed very accurately with
a circular lid. They are not all equally finished, some being much
more compact, and having the lid more closely fitted than others.
Some have irregular bulgings, and ragged laminated offsets on the
outer surface; but all are smooth and silky on the inside.... The
mouth of the tube, and the parts near it, are very strong; the walls
here often having a thickness of from one-eighth to one-fourth of an
inch; but the lower parts are much thinner. The lid is continuous
with the tube for about a third of its circumference, and this part
may be called the hinge, though it presents no structure peculiar to
itself; it is simply bent at a right angle, as is manifest, if a nest
be cut longitudinally through with scissors, the incision passing
through the midst of the lid. The mode of construction, I judge, from
examination of many nests, to be this. The spider digs a cylindrical
hole in the moist earth, with her jointed fangs or mandibles,
carrying out the fragments as they are dislodged. When the excavation
has proceeded a little way, she begins to spin the lining which
forms the dwelling. I conclude thus, because nests are occasionally
found a few inches in length, with the lid and upper part perfect,
but without any bottom, these being evidently in the course of
formation. I suppose that she weaves her silk at first in unconnected
patches, against the earthy sides, perhaps where the mould is liable
to fall in; and thus I account for the loose rough laminæ of silk
that are always found projecting from the outer surface. These are
overlaid with other patches more and more extensive, until the whole
interior walls are covered; after which the silk is spun evenly and
continuously all round the interior, in successive layers of very
dense texture, though thin. Under the microscope, with a power of 220
diameters, these layers are resolved into threads laid across each
other and intertwined in a very irregular manner; some are simple,
varying from 1/7000 to 1/2000 of an inch in diameter, and others are
compound, several threads, in one part separate, being united into
one of greater thickness which cannot then be resolved.... The mouth
of the tube is commonly dilated a little, so as to form a slightly
recurved brim or lip; and the lid is sometimes a little convex
internally, so as to fall more accurately into the mouth and close it.
"The thickening of the hinge by additional layers is, I think,
accidental only, as, out of the many specimens that I have examined,
only one or two had such a structure. In the neatest examples, the
lid is of equal thickness throughout its extent, agreeing also with
the walls for the first few inches of their depth."
Mr. Gosse says that he possesses one specimen of peculiar
compactness, which differs from all the others that he has examined
in having "a row of minute holes, such as might be made by a very
fine needle, pierced around the free edge of the lid, and a double
row of similar ones just within the margin of the tube. There are
about fifteen or sixteen punctures in each series, and they penetrate
through the whole substance, the light being clearly seen through
each hole. I do not think, as I have somewhere seen suggested, that
they are intended to afford a hold for the spider's claws when she
would keep her door shut against the efforts of an enemy, for what
would be the use of having them in the tube _close to the lid_, so
close that not the eighth of an inch intervenes between the surface
of the lid and that of the tube, when the former is tightly closed? I
would suggest whether they may not be air-holes, for so tight is the
fitting of the lid, and so compact the texture of the material, that
I should suppose the interior would be impermeable to air but for
this contrivance."[56] "The spider that inhabits this nest is black,
with the thorax of an exceedingly lustrous polish, its abdomen is
full and round, its legs very short."
[Footnote 56: I cannot myself think this explanation probable, and
should still be inclined to consider these punctures to be the claw
marks of the spider, as is the case in some European nests.]
Another form of this single door wafer nest is described by Mr.
Sells,[57] in which there is a hinge-like thickening of the silk
lining of the tube about an inch below the actual hinge of the door,
which it is suggested may serve to give additional elasticity.
This was not found, however, in all the nests examined, and Mr.
Sells conjectures that in newly constructed nests the lid may close
sufficiently firmly without this contrivance, and that it is only
added in older nests.
[Footnote 57: Mr. W. Sells. Notes respecting the Nest of _Cteniza
nidulans_, in Trans. Ent. Soc. ii. 207-210.]
Patrick Browne's figure, to which reference has been made above,
represents a nest with two doors, one applied against the other, at
the mouth of the tube, and it has often been asked what this could
possibly mean.
Some have thought that the drawing was fanciful, others that it was
made from an abnormal or injured nest. However, I believe that the
drawing, though rude, is, in fact, not very incorrect, and shows a
case of repair or enlargement of the nest, a subject to be treated of
more fully further on. There is a specimen exhibited in the British
Museum which in this respect very nearly corresponds with Browne's
figure; it is labelled "Nest of Trap-door Spider with two doors,
from the spider having enlarged its abode.--Jamaica." Here one sees
that the spider has prolonged its tube about half an inch beyond the
original mouth of the nest, where it has constructed a new mouth and
door, the old door standing straight up at the back of and behind the
new one.
I imagine that the explanation of this curious piece of cobbling may
be somewhat as follows:--When the nest was in its original state and
had but one door, this door became by some accident covered over with
earth to about the depth of half an inch, and the inmate was thus
imprisoned. Then the spider, being, like most other members of its
order, very unwilling to abandon its home, determined to clear away
the entrance to its nest, and to lengthen the tube so that it should
reach up to the new level of the surface of the earth.... If I am
right, this should rather be called a lengthening than an enlargement
of the tube.
The nests of the cork type (A, p. 79) may usually be distinguished
at a glance from those of the wafer type by the greater thickness
of the door, and by its manner of shutting, but a nest from Morocco
has been figured and described by Prof. Westwood,[58] which seems
intermediate between the two. The door in this case may perhaps be
considered as of the cork type, though it is very thin, for it does
fit into the mouth of the tube, which is bevelled to receive it.
[Footnote 58: Observations on the Species of Trap-door Spiders, in
Trans. of Entomological Soc., London, 1841-3, vol. iii. p. 175.
I wish to take the present opportunity of thanking Prof. Westwood for
having afforded me special facilities for examining this and other
specimens forming part of the very valuable collections under his
care at Oxford.]
These nests were forwarded with their living occupants (_Cteniza
[Actinopus] ædificatorius_) from Tangiers to Prof. Westwood, who
describes the nests as being "about four inches deep, slightly curved
within, about three quarters of an inch in diameter, the valve at the
mouth not being circular, but rather of an oval form, one side where
the hinge is placed being straighter than the other. The valve is
formed of a number of layers of coarse silk, in the upper layers of
which are imbedded particles of the earth, so as to give the cover
the exact appearance of the surrounding soil, the several successive
layers causing it, when more closely inspected, to resemble a small
flattened oyster-shell."
The resemblance between this nest and that of the West Indian species
is the more interesting as Prof. Westwood says that both belong to
the same genus, (_Cteniza_ or _Actinopus_ of different authors,)
and are so closely allied as to present scarcely any important
distinction but that of size.
We shall find, however, on comparing the nests of these trap-door
spiders and their occupants, that we cannot as yet make any rule as
to the kind of nest which we may expect from a given spider.
It will be seen that species belonging to the same genus, and closely
resembling one another, sometimes build dissimilar nests; while
others, belonging to different genera, and unlike in many important
respects, construct almost identical nests.
This is the more strange, because, if we examine the structure of the
claws and palpi, they often seem to be specially adapted to serve as
carding instruments and to play a very important part in the weaving
of the silk linings of the nest; and yet nests of the same type are
occasionally produced by spiders in which these appendages are quite
unlike, and dissimilar nests where the claws and palpi are to all
appearance identical.
Thus, for example, if the reader will examine the drawings of part
of the foremost right foot of _Cteniza fodiens_, figs. A, 9 and 10,
Plate VII., p. 88, with that of _Nemesia cæmentaria_, figs. A, 9 and
10, Plate VIII., p. 94, both of which make nests of the cork type,
he will see that in the former the last joint of the tarsus is armed
along the inner side, with many moveable spines, and that each of the
two curved terminal claws has only one very strong tooth near the
base; while the same joint of the latter (_N. cæmentaria_) has no
spines, and the claws have three minute comb-like teeth near the base.
On the other hand, in the reverse case, where the structure of the
same joint is very similar, the nests may be wholly unlike, as in
_Nemesia Eleanora_, Plate XII., p. 106, and _N. cæmentaria_, Plate
VIII., where the nest of the former is of the double-door unbranched
type, and that of the latter of the single-door cork type.
It is probable however that a fuller and closer comparison of, and a
more exact acquaintance with the several parts and their functions
might show us that all spiders which spin similar webs are furnished
with equivalent instruments, so that what one leg lacks another may
possess in some shape or another; brushes of stiff hairs in one
place, compensating for a toothed claw, or for a row of moveable
spines in another.[59]
[Footnote 59: The claws are probably of first-rate importance in this
respect and should be most carefully studied. M. Lucas has stated
that the claws of _Mygale Blondii_, and _M. nigra_ from Algiers, and
of _M. nigra_ and _M. avicularia_ from Brazil, are retractile like
those of a cat! Unfortunately the dwellings of these spiders have
not been described. See Lucas (H.) in Rev. et Mag. de Zoologie, sér.
2, tom. ix. 1857, p. 587, and Ann. de la Soc. Entom. de France, ser.
3, tom. v. p. cxx., and vi. p. clxxi. Another curious point in which
spiders differ is the presence or absence of viscidity in the hairs
which clothe their feet and palpi. Mr. Blackwall states (Spiders of
Great Britain and Ireland, vol. i. p. 13), that by far the greater
number of the sub-order _Territelariæ_, or _Mygalidæ_ as he terms
them, "have the inferior surface of their biungulate tarsi, and of
the digital joint of their pediform palpi, in the females, densely
clothed with compound, hair-like papillæ, constituting an apparatus
which, by the emission of a viscous secretion, enables them to
traverse the perpendicular surfaces of dry, highly polished bodies;
others have three pairs of spinners and are destitute of hair-like
papillæ on the legs and palpi."
The four species of trap-door spider on the Riviera, here described,
appear to form exceptions to this rule, however, for they all
remained helpless prisoners when placed in a glass tumbler, though
struggling vigorously for freedom.
When, however relying on this experience, I placed a number of
smaller spiders of different kinds in glasses for examination some
walked straight out without any difficulty, while others were unable
to climb up the sides.]
It would be interesting, from this point of view, to draw all the
parts which may be supposed to aid in the act of weaving, and so to
contrast the corresponding limbs of different spiders, the nests of
which are known, that one might see at a glance in what they differed
and agreed. I have done this for the falces and the last joint of
the foremost right foot of the four spiders figured in Plates VII.,
VIII., IX., and XII., but to make the case complete all the limbs
should be represented in the same way.
Of the two spiders which are shown with their cork nests in Plates
VII. and VIII., the purplish grey _Cteniza fodiens_, (Plate VII.)
appears to be much rarer than the brown striped _Nemesia cæmentaria_
(VIII.), at any rate at Mentone. I have hitherto only succeeded
in obtaining four specimens of the former, though I have searched
repeatedly for them at Cannes and Mentone, while the latter species
is tolerably common.
The nests are, however, often extremely hard to find, and in some
cases it is only by chance that I have been able to light upon them.
All these trap-door spiders seem usually to prefer rather moist
and shady places, and sloping banks or loose terrace walls where
the interstices between the stones are filled up with earth, and
concealment is afforded by the creeping lycopodium (_Selaginella
denticulata_), Ceterach, spleen-wort or maiden-hair ferns, with short
moss and splashes of white lichen to distract the eye.
It was from such a terrace wall at Mentone, on March 26, 1872, that
the nest A in Plate VII. was taken, the tube running obliquely back
into the earth between the stones, and the door being concealed by a
net-work of lycopodium, one spray of which had been allowed to grow
on its upper surface.
The tubes of these as of the other kinds of nest are sometimes
straight, but more frequently they are bent, and almost always take a
downward course.
The following is Mr. Pickard-Cambridge's description[60] of _Cteniza
fodiens_, the spider which constructs this nest.
[Footnote 60: The following description and remarks, printed in a
different type, have been kindly prepared for this work by the Rev.
O. Pickard-Cambridge, to whom I sent a series of specimens of the
spiders preserved in spirit of wine and their nests. My very sincere
thanks are due to Mr. Pickard-Cambridge for this assistance, which
will give to my publication a value in the eyes of Arachnologists
which it could not otherwise have possessed. To all those who wish
to study the true structural relations of the four spiders, the
habits of which are recorded in the following pages, these details
will prove of the highest importance; while those who are only
interested in the economy of these creatures can readily pass them
over. For observers in the field there is a very ready way of knowing
these four spiders apart, as it will be seen that when they are
somewhat alike the nests are different (_Nemesia meridionalis_ and
_N. Eleanora_), and when the nests are alike (_Cteniza fodiens_ and
_Nemesia cæmentaria_) the spiders are markedly dissimilar.]
[Illustration: _Plate VI._]
FAM. THERAPHOSIDES.
Gen. Cteniza, Latr.
Cteniza fodiens. Plate VII.
Syn. _Mygale fodiens_, Walck. _Ins. Apt._, i. p. 237.
_M. Sauvagei_, Ausserer, _Beiträge zur Kenntniss der Arachniden
Familie der Territelariæ (Thor.)_, p. 36.
Female adult length 10 lines.
_Cephalothorax_ oblong oval, somewhat truncate at each end, and of
a dull whitish-yellow brown colour, the normal grooves and furrows
are strongly marked, the caput is large and elevated, rounded on
the sides and slightly higher near the occiput than at the ocular
area, the junction of the thoracic segments is indicated by a
strong deep curved indentation, the curve directed backwards;
there are a few strong black bristles of different lengths within
the ocular space, and several others run backwards in the central
line to the occiput. The height of the Clypeus is equal to rather
more than the diameter of one of the foremost eyes. The _Eyes_ are
eight, and form a rectangular figure whose transverse diameter
is the longest, and whose fore side is a little shorter than
the hinder one; the longitudinal diameter is about equal to the
space between the two foremost eyes; these are the largest of the
eight, and are separated by an interval of very nearly two eyes'
diameters; the two central eyes are the smallest, and are distant
from each other just about one eye's diameter, the eyes of the
hinder row are in two pairs forming the hinder corners of the
rectangle, those of each pair are nearly contiguous to each other,
and the inner one of each is the smallest; these last in the figure
appear to be the smallest of the eight, but this arises from the
point of view whence the figure was drawn; the two central eyes
occupy as nearly as possible the centre of the figure formed by the
two foremost eyes, and the two inner ones of the hinder row, and
are seated on a large black spot. The _Legs_ are short, strong,
and similar to the Cephalothorax in colour, their relative length
appeared to be 4, 3, 1, 2, they are furnished with hairs, bristles,
and short strong spines. These latter are on those of the two first
pairs, situated chiefly in two longitudinal parallel rows beneath
the tibiæ, metatarsi, and tarsi; on those of the third pair they
are situated on the sides and upper sides of those joints, while
the fourth pair has them only beneath the metatarsi and tarsi; all
the tarsi terminate with three claws, the two superior ones are
much the longest and strongest, and have a single short strong
tooth inside near the base. Near the union of the femora and genuæ
of the legs of the fourth pair are numerous short strong spines,
hairs, and bristles. The _Palpi_ are similar in colour to the
legs; they are strong and about equal in length to the legs of the
second pair, and have a double longitudinal row of strong spines
widely separated and divergent from each other beneath them; the
digital joint (like the tarsi of the legs) is furnished with other
spines between these two rows; each palpus terminates with a single
untoothed curved claw. The _Falces_ are strong, prominent, rounded
in the profile line, and have some hairs, bristles, and spines near
their fore extremities; the longest and strongest of the spines
are three in number, and form a kind of transverse row or comb at
the extreme inner point on the upper side of each falx; besides
these there is a row of short tooth-like spines on either margin of
the furrow on the under side of each falx in which the fang lies
concealed when at rest. The _Maxillæ_ are short and strong; the
palpi issue from their extremity on the outer side, and the inner
extremity is somewhat prominent and pointed.
The _Labium_ is small, short, somewhat rectangular in form, and
broader than high; the apex is a little rounded, and furnished with
a single transverse row of small tooth-like spines.
The _Sternum_ is somewhat subtriangular in form, much broader
behind, where it is rounded on the outer angles.
The _Abdomen_ is short oval, very convex above, where it is of a
yellowish vinous brown colour, with a slightly darker longitudinal
tapering, indistinct central stripe on the fore part; it is
sparingly clothed with hairs, and the under side is of a pale dull
yellowish colour; the spinners are four in number, and those of the
superior pair are the strongest, three jointed and upturned.
Adults and immature examples (all females) were found in tubular
holes lined with silk and closed at the orifice with a strong solid
hinged lid, shutting into the opening like a cork.
The portions of nests at B and C in Plate VII. also belong to
_Cteniza fodiens_, the latter being very similar to A in its
surroundings, but having a rather thinner door, slightly hollowed out
above (C 1). The smaller nest shown shut at B and open at B 1,[61]
is admirably concealed by mosses and lichens, some of which actually
grow upon the door, and here two minute trap-doors, belonging
to infantine examples of a distinct species of spider (_Nemesia
meridionalis_), are seen on the left hand below.
[Footnote 61: It must be clearly understood that when the doors are
represented as standing open or ajar this is unnatural, as they
always close by their own combined weight and elasticity.]
It is not rare to find small colonies of nests of the same or
distinct species grouped closely together in this way, though I
greatly doubt whether one can safely assume their sociability from
this fact.
I have very seldom seen nests on the flat ground, where the door
would lie horizontally when closed, a sloping or nearly vertical bank
being usually chosen, where the door will fall to by its own weight.
In the Ionian Islands another species or variety of _Cteniza_,
described under the name of _Cteniza (or Mygale) ionica_, and
represented as being of an uniform yellow-brown colour, is said to
make its nests in the earth of the terraces round the roots of the
olive trees.
Mr. Saunders[62] gives admirable figures and descriptions which show
us at once that these nests, which he discovered in rather elevated
situations in the island of Zante, are of the cork type; but, in
this case, the entire door does not shut flush with the surface, as
in ordinary cork nests, but has a short spur-like projection above
and behind the hinge, serving, as is conjectured, like a lever, by
pressing on which from the outside the lid may easily be raised.[63]
When I come to speak of the manner of constructing and repairing
nests I shall have occasion to refer to these nests again.
[Footnote 62: Sydney Smith Saunders. Description of a Species of
Mygale from Ionia, in Trans. Ent. Soc. London, 1839, vol. iii. p.
160, Plate IX.]
[Footnote 63: I must own to some hesitation about accepting this
explanation, though I am not prepared to offer any other.]
I have not as yet found any nests on the Riviera which can be said to
correspond accurately with those of _Ct. ionica_, the only builders
of cork nests yet discovered in this district being _Cteniza fodiens_
and _Nemesia cæmentaria_.
This latter species is described by Mr. Pickard-Cambridge,[64] in the
following terms:--
[Footnote 64: See above, p. 88.]
Gen. Nemesia (Savigny).
Nemesia cæmentaria. Plate IX.
Syn. _Mygale cæmentaria_ (Latr.), _H. N. des Crust._ t. vii. p. 164.
_M. cæmentaria_ (Walck), _Ins. Apt._ i. p. 135.
Female adult, length 9 to 11 lines.
_Cephalothorax_ rather elongate, oval, and somewhat truncated at
each extremity; the caput is elevated and rounded on the sides and
upper part, but less elevated than in _Cteniza_; the normal grooves
and indentations are well marked, and the junction of the cephalic
and thoracic segments is indicated by a strong deep impression or
cleft, of a transverse, curved, or somewhat bent angular form, the
curve or angle directed forwards. The colour of the cephalothorax
is yellow-brown tinged with olive, the margins are paler, but
have no distinctly defined marginal band. On the hinder part of
the caput are three clear brown-yellow longitudinal stripes; the
central one reaches from behind the two hind central eyes to the
thoracic junction, the lateral ones converge a little to the same
point, but do not reach nearly, in fact not much more than half
way, to the eyes. The clypeus is of a clear brown-yellow colour
also, and on either side of it (extending from each fore lateral
eye), is an irregular patch of the same. The ocular region and
clypeus are furnished with a few strongish black bristles, and the
three yellow stripes above mentioned have a few more, those on the
central stripe being the longest and strongest, and disposed in a
single longitudinal row.
The _Eyes_, eight in number, are seated on a transverse oval
eminence, and form a rectangular figure, whose transverse diameter
is double the length of its longitudinal diameter: their relative
position is similar to that of _Cteniza_, but in the present
species they are smaller than in _C. fodiens_: those of the hind
central pair are the smallest of the eight, and each is very
nearly contiguous to the hind lateral on its side; the interval
between those of each lateral pair is small; the space between
the two central eyes of the eight is equal to an eye's diameter,
and each of these is separated from the hind central and fore
lateral nearest to it by a similar interval. The _Legs_ are strong,
moderately long, their relative length 4, 1, 3, 2?, but little
difference is observable between 1, 3, and 2; they are furnished
with hairs, bristles, and a few, not very strong, spines; each
tarsus terminates with three curved claws, the two superior ones
much the longest and strongest, and have a few small teeth near
their base inside.
The _Palpi_ are strong and similar in colour and armature to the
legs; each is terminated with a curved black claw.
_Falces_ strong, prominent, and rounded in the profile line;
they are furnished with hairs, bristles, and strong tooth-like
spines; the four strongest of these latter form a transverse row
at the inner extremity of each; besides these there is a row of
short tooth-like spines on the inner margin of the furrow on the
underside of each falx, in which the fang lies concealed when at
rest. The _Maxillæ_ are strong, with a small angular prominence at
their inner extremities (when looked at from beneath), and each
has three to four small dark-coloured teeth in a short, straight,
obliquely transverse row at the base on the inner side. _Labium_
broad but short, its breadth is double its height, and the upper
corners are rounded off. The _Sternum_ is of a somewhat pentagonal
form.
_Abdomen_ rather elongate oval, tolerably, but not excessively,
convex above; it is of a dull yellowish whitey-brown colour marked
and mottled above with dark chestnut brown; the markings are rather
irregular, but a general disposition in the form of a longitudinal
central, and oblique lateral, stripes or bars may be traced on the
hinder half; the superior spinners are short and three-jointed,
those of the inferior pair are exceedingly minute.
Adult females were found in nests similar to those of _Cteniza
fodiens_.
The cork nests are the simplest form of nest, with the exception of
those described above from Jamaica, and have constituted, up to the
present time, the only type known in Europe. Their chief claims to
our admiration lie in the perfection of workmanship which the doors
usually exhibit, and the marvellous concealment which they afford
when closed. These doors as a rule fit so tightly [thanks to the
accurate adjustment of their sloping sides to the bevelled lip of
the tube which receives them,] that they afford a certain amount
of mechanical resistance, even when the spider is away. But, after
examining a very large series of these cork nests, I find that there
is some variation in the degree of perfection attained in their work
by different individuals of the same kind. The mechanical resistance
is greater or less in proportion to the thickness and weight of the
door, and to the slope of its sides, and of the bevelled edges of
the tube; and in each of these details a marked difference may be
observed.
One might suppose from what has so often been repeated as to the
habits of _N. cæmentaria_, that, whenever any one attempts to open
the door, the spider, which is always at home in the day time, would
dart up from the bottom of the tube and endeavour to keep it closed
by holding on from within.
[Illustration: _Plate VIII._]
I cannot say what may take place during the summer months; but from
October to May I have but rarely found one of these spiders ready to
oppose me, though _Nemesia meridionalis_ and _N. Eleanora_ frequently
did so. Many times, wishing to provoke them, I have tapped at the
door in order to apprise the occupant of my arrival, or lifted it and
let it fall again, and always in vain, though the spider was there,
crouching at the bottom of her tube.
Indeed I can only recall six or eight instances in which this spider
did hold down her door, and on three of these she was captured.
I will now relate what I saw on one of these occasions,[65] for there
has been much speculation as to the manner in which the spider clings
to the door and offers the determined resistance which is experienced.
[Footnote 65: Mrs. Boyle was the first to witness this curious sight,
and my description of the resistance of the spider is almost an exact
repetition of hers to me. It is curious also that, following her
indications, I found the very nest and spider on which she had made
her observations, and every detail recurred again though several days
had elapsed between her visit and mine.]
No sooner had I gently touched the door with the point of a penknife
than it was drawn slowly downwards, with a movement which reminded
me of the tightening of a limpet on a sea-rock, so that the crown
which at first projected a little way above, finally lay a little
below the surface of the soil. I then contrived to raise the door
very gradually, despite the strenuous efforts of the occupant, till
at length I was just able to see into the nest, and to distinguish
the spider holding on to the door with all her might, lying back
downwards, with her fangs and all her claws driven into the silk
lining of the under surface of the door. The body of the spider was
placed across, and filled up, the tube, the head being away from
the hinge, and she obtained an additional purchase in this way by
blocking up the entrance.
I did not force the spider to release her hold, but, by a rapid
stroke with a long-bladed knife, cut out the upper part of the tube
with the surrounding mass of soil, and thus secured the trap-door and
its owner. This specimen is represented at fig. C, Plate VIII., where
the pin-point holes made by the claws may be seen in pairs round the
whole circumference of the flatter portion of the lower surface of
the door except on the side next to the hinge.
Whenever a spider resists in this way she must make these holes, but
I have very rarely seen them in other nests; this may perhaps be
accounted for by their having been effaced by the action of moisture
which would stretch the silk. However this may be, this specimen
showed the claw marks quite distinctly on my return to England after
the lapse of several weeks.
Much has been written about these marks, which are frequently spoken
of as holes purposely made in the silk in order to give the spider a
better purchase. It has also been stated that two holes may be seen
in the silk of the tube near the mouth on the side away from the
hinge, but these I have never been able to find. The door of nest A
in Plate VIII. is rather abnormal, as it is made up of two doors, the
smaller one being spun into the top of the one now in use. This is,
I believe, an abnormal and rather clumsy example of the ordinary way
of enlarging the nest, but of this we shall see more when we come to
speak of the construction and repairing of these nests generally.
Fig. B in this plate represents a moss-covered sod pierced by the
tube of a nest, the door of which is entirely concealed from view,
and only discovered when opened as at B 1.
This nest was found accidentally by Mr. Robert Lightbody, who
kindly brought it to me, its presence having been betrayed by the
tube, which he happened to cut through in digging up a plant. The
moss on the door grew as vigorously, and had in every way the same
appearance, as that which was rooted in the surrounding earth; and so
perfect was the deception that I found it impossible to detect the
position of the closed trap even when holding it in my hand. There
can be no doubt that many nests escape observation in this way, and
the artifice is the more surprising because there is strong reason to
believe that this beautiful door-garden is deliberately planted with
moss by the spider, and not the effect of a mere chance growth. I
shall adduce evidence in support of this statement by-and-by.
I alluded to the nest C (Plate VIII.) when speaking of the claw
marks which it exhibits, and that figured at D and D 1 in this plate
is merely an instance of a good example of this type. I have taken
nests of _N. cæmentaria_ both at Cannes and Mentone, and have little
doubt that this species will be discovered at many points along the
Riviera. I detected two abandoned nests of the cork type, which I
fully expect had belonged to _N. cæmentaria_, in an enclosed space
called the Campagne de Garonne in Marseilles itself. These nests lay
in the little mound of undisturbed earth between the divided trunks
of the small olive-trees, and I do not doubt that if I had had time
to search I should have discovered more nests, and perhaps others
which were still tenanted.
We now turn from the single-door nests to those with double doors,
and from the well known to the new types of structure.
In these we have a thin and wafer-like door at the mouth of the
nest, and from two to four inches lower down, a second and solid
underground door. These lower doors are characteristic of the
nests to which they belong, that of the branched nest (_Nemesia
meridionalis_, Plate IX.) being long and more or less tongue-shaped,
while that of the unbranched double-door nest (_N. Eleanora_, Plate
XII. p. 106) is somewhat horse-shoe shaped.
The surface doors of these two kinds of nest do not appear to
differ, and, though rather thinner, may be compared to those of the
single-door wafer kind from Jamaica.
The commonest form at Mentone is the branched nest, which may be
found in abundance in many of the loosely-built walls of the lemon
and olive terraces or on sloping banks, but they are rarely to be met
with on flat ground.
In the nests of _Nemesia meridionalis_ the tube, instead of being
simple, as it is in all other known nests, is invariably branched,
a second tube joining the first at the point where the lower door
is hung and forming with it an angle of about 45°. The main tube
descends and is frequently curved, or sometimes doubly bent like the
spout of a tea-kettle (A, Plate X. p. 100), while the branch ascends,
and in some few instances reaches the surface, though it is usually a
_cul de sac_ (Plate IX.)
[Illustration: _Plate IX._]
In the exceptional cases where the nests have two superficial
openings, one of the two surface doors always appears neglected and
going to decay, or is covered with earth which chokes the upper part
of its tube. The explanation of this probably is that the spider
found the original entrance blocked up or in some way unfitted for
use, and then prolonged what was the blind branch until it reached
the surface and replaced the former doorway. However this may be it
is certain that in the great majority of nests it will be found that
the branch ends in the earth, and is a _cul de sac_, and this I have
invariably observed to be the case in the nests of very young spiders
of this species (fig. B, Plate IX.)
The tube is frequently enlarged at the mouth, and forms a spreading
lip which the surface door is usually large enough to cover (A 1,
Plate IX.)
In these branched double-door nests the upper door does not fit into,
but merely lies upon, the mouth of the tube, the elasticity of the
hinge and its own weight being sufficient to keep it closed. The
lower door is suspended by a hinge placed at the apex of the angle
formed by the bifurcation of the tube, and is hung in such a manner
that it can either be pushed upwards so as to lie diagonally across
and block the main tube, or be drawn back so as to fit into and close
the entrance to the branch.
This will, I think, best be understood by reference to the drawings
of a small nest of this type given at B 1 and B 2 in Plate XI. p.
105, where the second door is shown in its two positions. This lower
door is from 1 to 1-1/2 lines thick, channeled above, but nearly
flat on the back, and of an elliptic form, with a loose appendage
at its lower end, the whole being made of earth enclosed in a case
of silk.[66] When the lower door is drawn back so as to close and
conceal the entrance to the branch, it lies in the same plane, and
closely corresponds in curvature with the lining of the main tube and
almost appears to form part of it (fig. A, Plate X. p. 100, and fig.
B 1, Plate XI. p. 105).
[Footnote 66: Since writing the above I have learned, thanks to a
better method which I have recently adopted for preserving the nests
for examination, that sometimes the lower door, instead of being free
within the tube and only attached to the lining by the hinge, is
surrounded on either side by a delicate silk web, which extends from
either edge of its lower surface to the silk walls of the tube below
and forms a sort of double gusset. This admits of the movement of the
lower door in the way described above, but perhaps serves, together
with the solid appendage at the extremity of the free end of the door
(that away from the hinge), to prevent the door from being driven too
far in an upward direction and thus becoming so tightly jammed as to
make the spider a prisoner in her own nest. I think it possible that
the lower door is always attached to the tube in this way, but, as
it parts readily from the silk on either side when the earth which
supports the tube is removed, it very frequently appears to be free,
as I have represented it in Plates IX., X., and XI.]
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.
[Illustration: _Plate X._]
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.
[Illustration]
[Illustration: _Plate XI._]
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.
[Illustration: _Plate XII._]
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.
[Illustration: Nemesia Eleanora ♂ Adult, natural size.]
Since the above description of the female of this species was
written, an example of the adult male has been most opportunely
discovered. It is much smaller than the female, its length being
only six lines. The _Cephalothorax_ is of an uniform clear
yellow-brown colour, tinged with orange, and thinly clothed with
a greyish pubescence: the oblique indentations marking the union
of the cephalic and thoracic segments are indicated by a strongish
black-brown band on either side, which becomes obsolete as each
approaches the other near the central curved indentation; there
are also two or three converging suffused blackish stripes on the
hinder slope. The relative length of the _Legs_ is the same in both
sexes, 4, 1, 2, 3, but in the male those of the fourth are longer
in proportion to those of the third pair than in the female; the
spines also on the legs are more numerous and stronger, the upper
sides of the femora of all the legs are deeply suffused with black,
while in the female this suffusion is not nearly of so marked a
character, though the genua of the different females examined
had a strong brown-black macula on the outer side of each, while
the corresponding maculæ in the single male examined were but
just visible; the three spines observed on the outer side of the
genua of the third pair of legs in the female are of even a more
marked character in the male, and hence they may be considered a
good and tangible specific difference from other nearly allied
species; the tibiæ of the first pair are considerably enlarged on
the under side at the fore extremity, where each is armed with
a single, longish, strong, slightly curved, pointed black spine
directed forwards (fig. _a_, 3). The _Abdomen_ is small and of an
oval form; its colours and markings resemble those of the female,
but on the hinder half of the upper side two or three indistinctly
traced pale angular bars or chevrons are formed by the distribution
of the black-brown colours and markings; the under side of the
abdomen is of a uniform pale whitish yellow, except the spiracular
plates, which are yellow-brown. The _Palpi_ are moderately long
and strong; the radial joint is longer than the cubital, and is of
a tumid and somewhat oval form, suffused over most of its surface
with dark brown, the rest of the palpus being of a yellowish-brown
colour; the digital joint is small and somewhat oblong-oval, curved
downwards, and very slightly concave on its inside; the palpal
organs consist of a nearly globular, basal, corneous bulb prolonged
into a strongish, curved, but not very long, pear-stem form, the
stem being distinctly cleft or bifid at its extreme point (_vide_
figs. _a_ 1, and _a_ 2), one portion of the bifid part is larger
than the other, though both are equal in length, and the stem of
the palpal bulb is directed transversely outwards, almost at right
angles with the digital joint.
Until the discovery of the male spider now described, and which is,
without doubt, the male sex of the female described immediately
before, this latter was thought to be the female of _Nemesia
Manderstjernæ_ (Ausserer), and it had indeed been so determined
by Professor Ausserer himself. But the form of the palpal organs
differs so decidedly from those of _N. Manderstjernæ_ (Ausserer,
_Beiträge ... der Territelariæ, Verhandl. Z. B. Gesllsch_: Wien,
1871, Bd. xxi. p. 170), that all doubts as to the present being
a distinct (and as it is believed to be) a hitherto undescribed
species, are removed. From M. Ausserer's description, the
pear shaped stem of the palpal bulb in _N. Manderstjernæ_ is
comparatively slender, ending in a fine and uncleft point, whereas,
in _N. Eleanora_, the stem is strong and its extremity cleft: other
differences are also observable in the two spiders, but this one is
well marked and the most tangible.
The specific name, _Eleanora_, now conferred upon the species, is
taken from the Christian name of the Hon. Mrs. Boyle, reference
to whom has been before made, and of whose kind exertions some
acknowledgment is thus permanently recorded.
In fig. A, Plate XII., the upper door, which, if closed, would be
entirely hidden by the long filmy mosses which surround and cover it,
is represented open; but it should be clearly understood that this is
artificial and not natural, as in reality these doors close of their
own accord by means of their weight and the elasticity of the hinge.
It will be seen that living mosses of two kinds are worked into the
upper surface of this door, which was admirably concealed. (fig. A 1,
Plate XII.).
It is chiefly in the absence of the branch and the different form
of the lower door that the nest of _Nemesia Eleanora_ differs from
that of _N. meridionalis_; and, as they inhabit the same localities,
it is only when one has dug down as far as the lower door that it
can be known to which of the two species the nest belongs. When once
this point is reached however, all doubt is at an end; for in this
case the unbranched double-door nest differs from the branched in a
way which any child could realize, though the respective spiders are
not very dissimilar when seen with the naked eye alone. This affords
a good instance of the benefit which may accrue to a collector from
a study of the habits of the creatures which he collects, for it is
certain that it was the nest in this case which first proclaimed the
distinctness of its tenant.
_Nemesia Eleanora_ is rather less common at Mentone than _N.
meridionalis_, but at Cannes I found the reverse to be the case. At
the latter place, on the northern slope of the little hill of St.
Cassien, branched and unbranched double-door nests may, however, be
found in tolerable abundance, the traps being frequently concealed by
fallen leaves from the cork oaks, which are woven into their upper
surface.
The nest of _N. Eleanora_ often has the upper part of the tube
prolonged above the surface of the ground and carried up through
mosses, grasses, and the like.
An example of this is seen in figs. B and B 1, Plate XII., in which
the upper part of the tube is represented with the surface door open
in the one case and shut in the other.
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.