WALCKENAERA. 
291 
In colour this species bears a close resemblance to WalcJcenaera acuminata. Its cephalo- 
thorax is oval, convex, and glossy, without any indentation in the medial line or marked pro¬ 
minence in front; the sternum is broad and heart-shaped. These parts, with the falces, 
maxillae, and lip, have a dark, brownish-black hue. The legs are hairy, and have a bright-rufous 
tint; each tarsus is terminated by three claws; the two superior ones are curved and pecti¬ 
nated, and the inferior one is inflected near its base. The palpi resemble the legs in colour. 
The abdomen is oviform, convex above, projecting over the base of the cephalo-thorax ; it is 
sparingly clothed with hairs, glossy, and of a deep-black hue, that of the branchial opercula 
being pale-yellow. 
The male is rather smaller than the female, and has a minute, conical, acute prominence, 
surmounted by a few fine hairs, situated within the trapezoid formed by the four intermediate 
eyes, immediately in front of the posterior pair. The radial joint of the palpi has two apo¬ 
physes at its extremity; the smaller projects on the under side, and the longer, which has a 
process near its base, on the outer side, curves outwards, in front of the digital joint, which is 
somewhat oval, convex and hairy externally, concave within, comprising the palpal organs; 
these organs are highly developed and complicated in structure, with a strong spine on the 
outer side, curved in a circular form. 
This rare spider is found under stones and on rails in the south of Lancashire, in York¬ 
shire, and in Denbighshire, and two females, one adult and the other immature, were taken 
by Mr. J. Hardy in Berwickshire, in the spring of 1849. 
The Tlieridion monoceros of M. Wider is nearly allied to this species, but it presents several 
points of difference, both in structure and colour (‘ Museum Senckenbergianum/ B. 1, p. 236, 
taf. 16, fig. 3). 
Walckenaera monoceros. PI. XX, fig. 205. 
Theridion monoceros, Wider, Museum Senckenb., Band i, p. 236, taf. 16, fig. 3. 
Argus — Walck., Hist. Nat. des Insect. Apt., t. ii, p. 361. 
Length of the male, ^th of an inch; length of the cephalo-thorax, T vth, breadth, ^th; 
breadth of the abdomen, ^th; length of a posterior leg, jth; length of a leg of the third 
pair, ith. 
The eyes are disposed in pairs on the anterior prominence of the cephalo-thorax, and are 
seated on black spots; those of each pair are near to each other, the lateral ones being placed 
on a minute tubercle in a line with the cephalo-thorax; the eyes of the posterior pair are rather 
the smallest of the eight, and with those of the anterior pair, which are the darkest coloured, 
form a narrow, oblong, quadrangular figure. The cephalo-thorax is long, oval, glossy, convex, 
particularly in the cephalic region, which is rather prominent and rounded; a small, conical, 
pointed process, slightly curved downwards, and provided with numerous short hairs, enlarged 
at the extremity, is situated in the space surrounded by the eyes, a little in advance of the 
posterior pair; the falces are small, conical, and vertical; the maxillae are short, and strongly 
