WALCKENAERA. 
311 
breadth of the abdomen, 5 ,th; length of a posterior leg, jth; length of a leg of the third 
pair, Ath. 
The legs are provided with hairs, and a few fine, erect spines, and are of a red-brown 
colour, with the exception of the tibise of the first and second pairs, which have a dark- 
brown tint; the fourth pair is rather the longest, then the first, and the third pair is the 
shortest; the two superior tarsal claws are curved and pectinated, and the inferior one is 
inflected near its base. The colour of the palpi is dark-brown. The cephalo-thorax is oval, 
convex, glossy, with slight furrows on the sides, and a minute indentation in the medial line; 
the falces are moderately strong, conical, armed with teeth on the inner surface, and inclined 
towards the sternum, which is broad, convex, and heart-shaped. These parts, with the lip, 
have a brownish-black tint, and that of the maxillae is reddish-brown. The abdomen is 
oviform, convex above, projecting over the base of the cephalo-thorax ; it is thinly clothed with 
hairs, glossy, and of a brownish-black hue; the sexual organs are rather prominent, and the 
colour of the branchial opercula is yellow. 
The male resembles the female in colour, and in the relative length of its legs. The 
anterior part of its cephalo-thorax is prominent, and divided into two segments by a transverse 
groove in front; the posterior segment is the larger, and has a pair of eyes seated on its 
summit, which is obtuse and rounded; the anterior segment is surmounted by a small, conical 
eminence, near the apex of which, in front, there are two minute processes curved upwards; 
at the base of this cone, immediately below the curved processes, the smallest pair of eyes is 
situated, the two lateral pairs being placed on the sides, of the anterior segment. The 
radial joint of the palpi is larger than the cubital, and consists of three parts ; one situated in 
front, which is broad, and round at the extremity ; a smaller one underneath of a similar form ; 
and a long, slender one on the inner side, which passes obliquely before the digital joint; 
this joint is somewhat oval, with a prominent lobe on the outer side; it is convex and hairy 
externally, concave within, comprising the palpal organs, which are highly developed, com¬ 
plicated in structure, with a fine spine at their extremity, enveloped in membrane, and curved 
in a circular form ; they are of a reddish-brown colour. 
As the Argus anticus and Argus apicatus of M. Wackenaer are the same, and are identical 
with Walckenaera antica, they are included among the synonyma of that species, which was 
observed on rails near Llanrwst, in November, 1837, and again in May, 1838. 
Walckenaera saxicola. PI. XXI, fig. 226. 
Walckenaera saxicola, Camb., Annals and Mag. of Nat. Hist., third series, vol. vii, 
p. 440. 
Length of the female, Ath of an inch; length of the cephalo-thorax, 5 \th, breadth, roth; 
breadth of the abdomen, 3 tnd; length of a posterior leg, Ath; length of a leg of the third 
pair, Ath. 
41 
