The sexes resemble each other in the design formed by the yellow marks on the
abdomen, but the female is rather larger than the male, and is without strong spines on
the legs.
Some difference of opinion has existed among arachnologists as to the position this
spider should occupy in a systematic arrangement of the Araneidea; but there does not appear
to be any sufficient reason for removing it from the T lerid ia , to which it seems to be most
nearly allied by its organization.
In Denbighshire, this species is found among heath, but it is of rare occurrence. The
radial and digital joints of the palpi are so closely connected in the male, as scarcely to
present any perceptible trace of their union; in short, as they appear to be incapable of
separate motion, there seems to be an impropriety in regarding them as distinct joints.
Theridion filipes. PI. XIV, fig. 136.
Theridion filipes, Blackw., London and Edinb. Phil. Mag., third series, vol. viii,
484.
—— — Blackw., Annals and Mag. of Nat. Hist., second series, vol. viii,
p. 447.
Linyphia concolor, Wider, Museum Senckenb., Band i, p. 267, taf. 18, fig. 3.
— — Walck., Hist. Nat. des Insect. Apt., tom. ii, p. 270.
Length of the female, gth of an inch; length of the cephalo-thorax, ^th, breadth, 35th ;
breadth oT the abdomen, ^ th ; length of an anterior leg, # h s ; length of a leg of the third
pair, |jths.
The four intermediate eyes form a trapezoid, whose anterior side is the shortest, and those
constituting each lateral pair are seated on a small tubercle, and are contiguous; the posterior
eyes of the trapezoid are the largest, and the anterior ones much the smallest of the
eight. The cephalo-thorax is oval, convex, glossy, with an indentation in the medial line;
the falces are powerful, conical, armed with teeth on the inner surface, rather divergent at the
extremity, and inclined towards the sternum, which is heart-shaped; the maxillae are enlarged
at the base, where the palpi are inserted, obliquely truncated at the extremity, on the outer
side, and inclined towards the lip, which is semicircular and prominent at the apex; the legs
and palpi are long, slender, and provided with hairs and some fine erect spines. These parts
have a brown colour, the falces and maxillae being tinged with red. The first pair of legs is
the longest, then the fourth, and the third pair is the shortest; each tarsus is terminated by
three claws; the two superior ones are curved and slightly pectinated, and the inferior one is
inflected near its base. The abdomen is oviform, convex above, and projects over the base
of the cephalo-thorax; it is thinly clothed with hairs, glossy, and of a brown-black colour,
tinged with olive; a long, slender, cylindrical, semitransparent process, directed backwards,
is connected with the sexual organs; and the colour of the branchial opercula is dark-brown.
Some individuals have a series of obscure, pale, angular lines, whose vertices are directed
forwards, extending along the middle of the upper part of the abdomen.
The male is rather smaller and darker coloured than the female. The cubital and radial
joints of its palpi are short; the latter, which is the stronger, is prominent on the inner side
and in front, several long bristles being connected with the frontal prominence; the digital
joint is of a long, irregular oval form, having a projection on the outer side, and two
smaller ones on the upper part, near its articulation with the radial joint; it is convex and
hairy externally, concave within, comprising the palpal organs, which are highly developed,
complicated in structure, and of a red-brown colour; a strong, corneous spine, enveloped in
a delicate, transparent membrane, originates in the superior part of these organs, and, bending
downwards, extends along their inner side a little beyond the termination of the digital joint,
its extremity being curved outwards.
Theridion filip es is allied to the spiders belonging to the genus Neriene by the disposition
and relative size of its eyes, and to those of the genus IAnyphia by the length and delicacy of
its limbs; but the structure of its maxilhe and the relative length of its legs have caused it to
be classed with the Theridia. It occurs under stones'in woods in Denbighshire, Lancashire,
and Berwickshire.
An adult female of this species, captured in March, 1835, presented an. anomaly in
organization very unusual in this order of animals; it had a supernumerary eye situated
between the two small ones constituting the anterior pair of the trapezoid.
M. Walckenaer has inadvertently placed the L inyphia concolor of M. Wider, which is
identical with Theridion filip es, among the synonyma of Argus graminicolis, having previously
described it as a distinct species under the name conferred upon it by M. Wider (‘ Hist. Nat.
des Insect. Apt./ t. ii, pp. 270, 351).
Genus PHOLCUS {Walck),
Eyes seated on an anterior prominence of the cephalo-thorax; three, closely grouped on
each side, form a compact triangle, and the other two, placed transversely between the
triangles, are the smallest of the eight.
M a xilla long, narrow, tapering from the dilated base to the extremity, and inclined
towards the lip.
L ip large, contracted at the base, dilated in the middle, and rounded at the apex.
Legs very long and slender; the first pair is the longest, then the second or fourth, and
the third pair is the shortest.