WALCKENAERA. 
301 
WALCKENAERA AGGERIS. PI. XXI, fig. 216. 
Walckenaera aggeris, Cambridge, Annals and Mag. of Nat. Hist., third series, vol. v, 
p. 173. 
Length of the female, / 4 th of an inch; length of the cephalo-thorax, 7 , 5 th, breadth, 4 th; 
breadth of the abdomen, 4 th; length of a posterior leg, Toth; length of a leg of the third 
pair, 4 th. 
The eyes, which are nearly equal in size, are disposed on the anterior part of the cephalo- 
thorax, high above the frontal margin; the four intermediate ones form a narrow, elongated 
trapezoid, whose anterior side is the shortest; and those of each lateral pair are seated obliquely 
on a minute tubercle, and are contiguous. The cephalo-thorax is long, oval, convex, some¬ 
what glossy, without an indentation in the medial line, and has an oblong, vertical space 
between the posterior and anterior intermediate pairs of eyes clothed with short hairs; the 
falces are small, conical, vertical, and armed with teeth on the inner surface ; the maxillae are 
greatly inclined towards the lip, which is semicircular and prominent at the apex; and the 
sternum is broad, convex, and heart-shaped. These parts are of a dark-brown hue, the falces 
and maxillae being much the palest. The legs are slender, provided with hairs, and of a 
yellowish-red colour, being paler at the articulation of the joints; the fourth pair is the longest, 
then the first, and the third pair is the shortest; each tarsus is terminated by three claws; the 
two superior ones are curved and pectinated, and the inferior one is inflected near its base. 
The palpi are short and resemble the legs in colour. The abdomen, which has a black hue, 
is oviform, glossy, sparingly clothed with hairs, convex above, and projects over the base of 
the cephalo-thorax. 
The sexes are similar in colour, but the male, which is rather the smaller, has an inden¬ 
tation directed backwards from each lateral pair of eyes, and the oblong, vertical space 
between the two intermediate pairs of eyes forming the trapezoid is densely covered with short 
hairs. Its palpi are of a yellowish-red hue, with the exception of the digital joint and the 
extremity of the radial joint, which have a brownish tint; the humeral joint is curved towards 
the cephalo-thorax, and the radial, which is stronger than the cubital joint, is produced at its 
extremity, in front, and has an acute apophysis on its outer side; the digital joint is oval, with 
a small lobe near its extremity, on the outer side; it is convex and hairy externally, concave 
within, comprising the palpal organs, which are highly developed, prominent, complicated in 
structure, and of a reddish-brown colour. 
Males and females of this spider were captured at Southport, in the summer of 1859, by 
the Rev. 0. P. Cambridge. 
