Epeira diadema. PI. XXVI, fig. 258.
Ejpeira diadema, Walck., Hist. Nat. des Insect. Apt., torn, ii, p. 29.
— — Latr., Gen, Crust, et Insect., tom. i, p. 106.
Sund,, Ygt. Acad. Hand]., 1832, p, 235,
— S i l l Halm» ^ Arachm, Band ii, p. 22, tab. 45, fig. 110.
^ — Koch, Uebers, des Arachn. Syst,, erstes Heft, p. 2.
— ^ Koch, Die Araghii., Band xi, p, 103, tab. 384, fig. 910.
Blaclcw., Annals and Mag. of Nat. Hist., second series, vol. x, p. 188,
Titulus 2, Lister, Hist. Animal. Angl. De Aran., p. 28, tab. 1, fig. 2.
Length of the female, fibs of an in ch ; length of the cephalo-thorax, 1th, breadth, 1th ■
breadth o f the abdomen, |th s ; length of an anterior leg, Jths; length of a leg of the third
pair, I.
The cephalo-thorax is convex, clothed with pale yellowish-brown hairs, compressed
before, truncated in front, rounded on the sides, and has a large indentation in the medial
lin e ; it is o f a pale yellowish-brown colour, with a fine, brown line on the margins, a broad,
dark-brown band extending along each side and in front, and another, of the same hue, in
the middle, which increases in breadth as it approaches the eyes, The four intermediate
eyes are seated on a slight protuberance and nearly form a square, those of each lateral
pair being placed obliquely on a tubercle and almost in contact- The falces are short,
strong, conical, vertical, armed with teeth on the inner surface, and o f a brownish-black
colour, the extremity having a yellowish-brown hue. The maxilla? are straight, powerful,
and greatly enlarged at the extremity, which is rounded; the lip is nearly semicircular, but
somewhat pointed; and the sternum is heart-shaped, with prominences on the margin,
opposite to the legs and lip. These parts are o f a blackish colour, with the exception o f the
extremities of the maxillse and lip, which have a yellow tint. The legs are robust, provided with
hairs and numerous erect spines, and o f a yellowish-brown colour, with dark.brown annuU; each
tarsus is terminated by three claws of the usual structure, and below them there are several
smaller ones. The palpi resemble the legs in colour, and have a curved, pectinated claw at
their extremity. The abdomen is large, somewhat oviform, with a slight, obtuse, conical
protuberance on each side of the anterior extremity of the upper part, sparingly clothed with
hairs, convex above, and projects greatly over the base o f the cephalo-thorax; on the upper
part there is a brown, leaf-like mark, which decreases in breadth as it approaches the spinners,
and has dark, sinuous margins finely bordered with white, and white spots in its anterior
region ; it is bisected longitudinally by a line consisting o f white or pale-yellow streaks and
spots, which is intersected by three similar lines, giving it the form of a triple cross; on each
side of the leaf-like mark there is a broad, sinuous, yellowish-brown band obscurely spotted
with white; the sides and under part are of a dark-brown hue, mottled with dull
yellowish-white, and along tbe middle of the latter there is a broad, brownish-black band,
bordered anteriorly by two yellowish-white lines which are enlarged at their posterior
extremity; a long, curved, wrinkled, membraneous, flesh-coloured process, directed backwards,
is in connexion with the prominent sexual organs; and the branchial opercula are of
a pale-brown hue, the inner margin having a tinge o f yellow. This species varies from light
yellowish-brown to brownish-black, but, notwithstanding the differences in its predominant
tint, it may readily be distinguished by the peculiarity of the design formed by the distribution
o f the colours on its abdomen.
Though the male bears a marked general resemblance to the female, yet it differs from
her in various particulars. It is much smaller, and the dark bands on its cephalo-thorax are
not so conspicuous; its falces are less powerful, and of a yellowish-brown h u e ; a small,
conical process occurs on the outer side of its maxillse, immediately before the insertion of
the palpi, and these organs, with the lip and sternum, are of a red-brown colour, with the
exception of the extremities of the maxillse and lip, which have a yellowish-brown tint, the
coxse of its anterior legs have a conical process at the extremity, on the under side, and a
similar process is situated at the base of the coxse of the second pair, whose tibiae are more
robust than those of the other legs, and are provided with two parallel rows of short, strong,
black spines on their anterior surface ; its palpi are short, and of a yellowish-brown h u e ,
the cubital joint is rather prominent at its extremity, in front, whence project two long
bristles, and the radial joint is protuberant on the outer side; the digital joint has somewhat
of a narrow, elongated, oval form, with an obtuse, brownish-black process at its base, curved
outwards ; it is convex and hairy externally, concave within, and comprises the palpal
organs, which are very highly developed, very protuberant, and complicated in structure,
having a pale, prominent process on the outer side, and several pointed ones at the^ extremity,
and their colour is red-brown, intermixed with yellowish-brown. The convex sides
of the digital joints are directed towards each other.
This spider is plentiful in Great Britain and Ireland, constructing an extensive net, without
any circular opening at the centre, among gorse, heath, and bushes. In common with
the other species belonging to the genus Epeira, its head is always directed downwards
when occupying a position at the centre of its snare, and as it is supported on such occasions
chiefly by the sustentacula and a line connecting the spinners with its station, the reason of
the fact is apparent.
Epeira diadema and some of its congeners envelope their prey in a sheet of web by the
following curious process. Causing the victim to rotate by the action of the third pair of
legs and the palpi, the first pair of legs also being frequently employed in a similar manner,
they extend the spinners laterally, and applying to them alternately the sustentaculum of each
posterior leg, they seize and draw out numerous fine lines in the form of a fillet, which they
attach to their revolving prey, and thus involve it in a dense covering of silk from one extremity
to the other. By means of this stratagem they are capable of overcoming formidable
and powerful insects, such as wasps, bees, and even large beetles.
In October the female of this species attaches to the inferior surface of stones a sub-
globose cocoon of yellow silk of a loose texture, measuring two thirds of an inch in diameter,
in which she deposits between 700 and 800 spherical eggs, of a yellow colour, agglutinated
together in a lenticular form. Withered leaves and bits of dry fern are frequently distributed
on the exterior surface of the cocoon. After deserting this nidus, the young spin a few lines,
on which they group themselves into a compact mass, somewhat resembling the granulated
fruit of the Bubi.