318 LINYPHIIDiE.
above, projecting over the base of the cephalo-thorax; it is thinly clothed with hairs, glossy,
and black.
Adult males of this interesting species were taken on iron-rails at Crumpsall Hall, in
the autumn of 1832, and it has since been met with, at different seasons of the year, in
various parts of Lancashire, Yorkshire, Cheshire, Dorsetshire, Denbighshire and Caernarvonshire.
Little is known as regards its economy, except that it is active during the day,
decidedly aeronautic, making frequent ascents into the atmosphere, and that it can exist for a
long period of time immersed in water.
This spider, on which the genus Savignia was founded, was supposed, when discovered,
to have only six eyes. Since then it has been found to possess an additional pair of visual
organs, difficult to be discerned, situated towards the front of the apex of its conical cephalic
prominence; consequently it had to be removed from the tribe Senoculina, in which a place
had been assigned to it, to the genus Walckenaera, with the spiders of which genus it is
connected by marked relations of affinity.
Genus—Pa c h y g n a t h a , Sund.
Eyes arranged on the anterior part of the cephalo-thorax, in two transverse rows ; the
four intermediate ones form a square, those of each lateral pair being placed obliquely on a
small tubercle, and nearly contiguous.
M axilloe long, inclined towards the lip, slightly dilated at the extremities, which converge
abruptly and are in contact.
L ip large, triangular, pointed or rounded at the apex.
Legs long and slender j the first pair is the longest, then the second, and the third pair is
the shortest.
Falces very powerful, diverging widely at their extremities.
Pa ch y g n at h a Cl b r c k i i. PI. XXII, fig. 233.
Pachygnatha Clerckii, Sund., Yet. Acad. Handl., 1829, p. 208, and 1832, p. 258.
— Blackw., Annals and Mag. of Nat. Hist., second series, vol. ix,
p. 466.
— Listen , Koch, Uebers. des Arachn. Syst., erstes Heft., p. 10.
— — Koch, Die Arachn., Band xii, p. 142, tab. 430, fig. 1064.
Manduculns ambiguus, Blackw., Lond. and Edinb. Phil. Mag., third series, vol. iii,
p. 111.
— Blackw., Research, in Zool., p. 359, pi. 3, figs. 3— 5.
Theridion maxillomm, Hahn, Die Arachn., Band ii, p. 37, tab. 53, fig. 122.
Linyphia maxillosa, Walck., Hist. Nat. des Insect. Apt., tom. ii, p. 267.
— Clerckii, Walck., Ibid., tom. ii,-, p. 270.
PACHYGNATHA. 319
Length of the female, ,th of an inch; length of the cephalo-thorax, jth, breadth, ^th ;
breadth of the abdomen, jth ; length of an anterior leg, §ths; length of a leg of the third
pair, 3th.
The cephalo-thorax is large, convex, glossy, marked with minute punctures, and has an
indentation in the medial line ; it is compressed before, rounded on the sides and in front, and
is of a light, reddish-brown colour, with a longitudinal black band in the middle, another on
each side, and a short, black streak directed backwards from each lateral pair of eyes. The
falces are convex in front, armed with teeth on the inner surface, and a long, moderately curved
fang at their extremity; they have a light, reddish-brown hue, and that of the maxillae and lip
is dark, red-brown, the latter being the darker. The sternum, which is heart-shaped and.
marked with minute punctures, is rather darker coloured than the cephalo-thorax. The legs
are sparingly supplied with hairs, and have a pale, yellowish-brown tin t; each tarsus is terminated
by three claws; the two superior ones are curved and finely pectinated, and the inferior
one is inflected near its base. The palpi resemble the legs in colour, and have a curved,
pectinated claw at their extremity. The abdomen is oviform, convex above, projecting over
the base of the cephalo-thorax; it is thinly clothed with short hairs, and the upper part, which
is of a yellowish-brown colour, tinged with olive, is irregularly bordered with black ; a narrow,
longitudinal band of a pale-yellow hue, having its anterior half bordered with black and
comprising a slender black streak, occupies the medial line, and a broad, dull-yellow band,
which is palest at its superior margin, and is tinged with light-brown below, extends along
each side; the under part is of a yellowish-brown colour, a band of a deeper shade, bounded
laterally by a faint yellow line, extending along the middle; and the branchial opercula have
a yellow tint. This species varies considerably in colour.
The male is smaller than the female, and its abdomen is more distinctly marked, the
upper part being almost black, and the medial and lateral bands nearly white in some individuals.
Its falces have an obtuse, conical process near the insertion of the fang, which latter
appendage has a small indentation about the middle, externally, and a corresponding projection
within the curve. The radial joint of the palpi is longer than the cubital, and clavate;
the digital joint consists of two parts; the shorter and slenderer part is connected with the
palpal organs on the upper side, and the longer is in contact with the same organs on the
inner side, and extends a little beyond them; the palpal organs are glossy and globular at the
base, with a pointed process anteriorly, which has the appearance of being somewhat twisted,
and are of a very dark, reddish-brown colour, approaching to black.
Arachnologists, in their endeavours to identify the species constituting the genus Pachygnatha
of Professor Sundevall, have involved their synonyma in a labyrinth of such perplexing
intricacy as to render any attempt at revision extremely difficult. In submitting the result
of a careful investigation of the subject to the consideration of zoologists, a hope is entertained
that it may tend to facilitate a more accurate knowledge of this small but interesting group.
The Pachygnatha L iste n of M. Koch and the L inyphia maxillosa of M. Walckenaer are
evidently the same as Pachygnatha C lerckii; but the Theridion vernale of M. Hahn and the
Pachygnatha L iste n of Professor Sundevall, which are included by M. Walckenaer among the
synonyma of L inyphia maxillosa, must not be confounded with that species and with each
other, Theridion vernale being identical with the Pachygnatha L eg eerii of Professor Sundevall.
42