Encyclopaedia Britannica > Volume 3, Anatomy-Astronomy

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A R A C H N I D E S.
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Anch- anterior pairs ; while in some the third and fourth pair are
aides, the most extended. The eyes, in their general dispo-
sition, do not form a crescent, or the segment of a circle.
Tkibe I.—TuBITELjE.
Spinners cylindrical, close to each other, directed back¬
wards. The feet are robust; the first and last pair are
the longest.
Genus Clotho, Walckenaer. Uroctea, Dufour.—Man¬
dibles very small, capable of little extension, and with¬
out teeth. Crotchets small, body short, legs long, the
third and fourth pair rather longer than the preceding.
The eyes are disposed as in genus Mygale. The max¬
illae have on their external side a slight dilatation at
the insertion of the palpi, and terminate in a point.
The languette is triangular. The superior or lateral
spinners are the longest; but the most peculiar cha¬
racter, according to M. Dufour, is the existence, in the
I position of the intermediate spinners, of a pair of comb¬
shaped valves, which open or close at the will of the
animal.
Sp. b-maculata.—Body about an inch in length, of a
chesnut-brown colour ; the abdomen black, with five small
round yellowish spots, of which four are disposed trans¬
versely in pairs, and the fifth is single and posterior.
This species was found in Egypt by M. Savigny. It
occurs in Dalmatia, and near Montpellier; also in Cata¬
lonia, and other parts of Spain. Its manners have been
described by M. Dufour.
Genus Drassus, Walck.—Mandibles robust, project¬
ing, toothed beneath. Maxillae obliquely truncated at
their extremity. The eyes are nearer the anterior edge
of the thorax, and the line formed by the four posterior
exceeds in length that formed by those on the anterior
line. The fourth and second pair of feet are obviously
longer than the others. The legs and first joints of
the tarsi are armed with sharp points.
The spiders of this genus live under stones, in the
clefts of walls, and among leaves. They form little
dwelling-places of white silk. The cocoons of some are
orbicular, flattened, and composed of two valves applied
one against another.
Sp. Relucens.—Small, cylindrical, with a yellow tho¬
rax, covered with a purple silky down. The abdomen is
thin, red, and green, with metallic reflections, and two
transverse lines of golden yellow, of which the anterior is
arched. One variety has also four additional golden spots.
The species is generally found running on the ground.
It is common in the environs of Paris, and is one of the
most beautiful of the tribe.
Genus Segestria, Latr.—Eyes six, of which four are an¬
terior on a transverse line, and two posterior, placed on
each side behind the two lateral eyes of the preceding
line. The languette is elongated and almost square.
The first and second pair of feet are the longest, and
the third pair the shortest.
The species of this genus spin cylindrical elongated
webs in the clefts of old walls, in which they lie concealed,
with their anterior pair of legs stretched forwards. Di¬
vergent threads of glutinous silk border the external open¬
ing to their habitation, and form a net for the capture of
their insect prey.
Sp. Senoculata.—Thorax blackish-brown. Abdomen
oblong, grayish, with a longitudinal band of blackish spots.
Legs pale brown, obscurely banded. Inhabits rocks and
old buildings.
Genus Aranea, Latr. Tegeneria, Walck.—The two
upper spinners conspicuously longer than the others.
ic four anterior eyes placed in a curved line, bending Arach-
backwards. . The first and last pair of legs the longest, mdes.
I his genus inhabit the interior of our dwellings; also
the angles of old walls, on plants, hedges, &c. They
construct large webs, nearly horizontal, at the higher
part of which is a tube or tunnel, where the spider lies
concealed. 1
Sp. Domestica.—Of a livid ash colour. Thorax of the
male without spots. On that of the female there is on
each side a blackish band. Abdomen blackish, with a
longitudinal spotted band on the back.
This is the most frequent inhabitant of our houses, and
an object of more than common aversion. It sometimes
attains to a large size. According to Homberg, it is sub¬
ject, especially in the kingdom of Naples, to a disease
which renders it more than usually hideous. Its body
becomes covered with scales, among which a number of
mites engender. Geoffroy was of opinion that a spider
was supplied only with a certain portion of spinning ma¬
terial ; that if the web was intentionally destroyed, and an
individual frequently obliged to reconstruct its web, it be¬
came at last incapable of further exertion in that line, and
would probably perish for want of the usual means of sub¬
sistence.
The spiders of this country are entirely harmless, from
their want of power to pierce the skin. But that they
are furnished with a poisonous liquid, which they instil
into the wound of their victims, cannot be doubted. Oli¬
vier, indeed, reports, that a farmer in one of the Isles
d’Hieres was bitten by a large spider while turning a
sheaf of wheat. The wound occasioned at first only a
slight inflammation, so trivial that it was for some time
neglected, till its increase created alarm. Gangrene and
death ensued. They may be taken internally with im¬
punity. “ J’ai vue,” says Latreille, “ le celebre astronome
Lalande avaler de suite quatre gros individus de cette
espece.” (A. domcstique.)
Genus Argyroneta, Latr.—Maxillae inclined upon the
languette, of which the form is triangular. The four
central eyes form a quadrangle; the lateral pair of each
extremity are grouped together, and placed on a small
eminence.
Sp. Aquatica. Aranea Aqvatica, Lin. Geoff.—Of a
blackish-brown colour, the abdomen deeper, surface silky,
the back with four impressed points. Lives in ditches arid
slow-running waters, beneath the surface of which it spins
a beautifully constructed web. “ The habitation of ara-
nea aquatica, the other spider to which I alluded, is
chiefly remarkable for the element in which it is con¬
structed, and the materials that compose it. It is built
in the midst of water, and formed in fact of air! Spiders
are usually terrestrial; but this is aquatic, or rather am¬
phibious : for though she resides in the midst of water,
in which she swims with great celerity, sometimes on her
belly, but more frequently on her back, and is an admi¬
rable diver, she not unfrequently hunts on shore, and
having caught her prey, plunges with it to the bottom of
the water. Here it is she forms her singular and unique
abode. She would evidently have but a very uncomfort¬
able time were she constantly wet; but this she is saga¬
cious enough to avoid, and, by availing herself of some
well-known philosophical principles, she constructs for
herself an apartment, in which, like the mermaids and
sea-nymphs of fable, she resides in comfort and security.
The following is the process:—First she spins loose
threads in various directions, attached to the leaves of
aquatic plants, which may be called the frame-work of
her chamber; and over them she spreads a transparent
varnish resembling liquid glass, which issues from the