PACHYGNATHA. 
319 
Length of the female, jth of an inch; length of the cephalo-thorax, ^th, breadth, Ath ; 
breadth of the abdomen, |th; length of an anterior leg, §ths; length of a leg of the third 
pair, jth. 
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 w'ith 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 tint; each tarsus is termi¬ 
nated 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 indivi¬ 
duals. 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 projec¬ 
tion 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 t'he 
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 Pachy- 
gnatha 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 Pacliygnatha Listen of M. Koch and the Linypliia maxillosa of M. Walckenaer are 
evidently the same as Pacliygnatha Clerckii; but the Theridion vernale of M. Hahn and the 
Pacliygnatha Listen of Professor Sundevall, which are included by M. Walckenaer among the 
synonyma of Linypliia maxillosa, must not be confounded with that species and with each 
other, Theridion vernale being identical with the Pacliygnatha Legeerii of Professor Sundevall. 
42 
