Mr. BuackwaLv's Descriptions of new Species of Spiders. 639 
minent 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 a 
delicate membrane, and curved in a circular form; they are of a reddish 
brown colour. 
Males and females of this species were found on rails near Llanrwst in No- 
vember 1837, and May 1838. 
25. Walckenaéra pumila. Cephalo-thorace mandibulis maxillis labio sterno- 
que saturaté pedibus palpisque rufescenti-brunneis ; pedum pari 4to 
paulo longiore, dein 1mo, 3tio brevissimo ; abdomine nitente nigro. 
Maris cephalo-thorax anticè elevatus obtusus utrinque indentatione 
instructus. 
Length of the female 45th of an inch; length of cephalo-thorax yy; breadth 
35; breadth of abdomen Ag; length of a posterior leg 5%; length of a 
leg of the third pair Pg. 
Cephalo-thorax oval, glossy, depressed on the sides, which are marked with 
slight furrows diverging from the upper part to the margins, and having 
an indentation in the medial line of the posterior region. Mandibles 
conical, armed with teeth on the inner surface, and inclined towards the 
‘sternum, which is broad and heart-shaped. Maxillæ inclined towards 
the lip, which is semicircular and prominent at the extremity. These 
parts are of a dark brown colour, the mandibles and maxillae being the 
palest. The lateral eyes are the largest, and the anterior ones of the tra- 
pezoid the smallest of the eight. Legs and palpi reddish brown, Fourth 
pair of legs rather the longest, then the first, third pair the shortest. 
Abdomen oviform, convex above, projecting over the base of the cephalo- 
thorax ; it is thinly clad with hairs, glossy and black. Plates of the spi- 
racles dull yellow. 
Ihe male is rather smaller than the female, but resembles her in colour 
and in the relative length of his legs. The anterior part of the * 
thorax is elevated, but obtuse, with an oblong indentation on each side, 
extending backwards from the lateral eyes. Fourth joint of the palpi 
shorter than the third; it is produced at the extremity, on the inner side, 
