Mr. Blackwall's Descriptions of new Species of Spiders. 635 



21. Walchenaera bicolor. Maris cephalo-thorace mandibulis maxillis labio 

 sterno pedibus palpisque brunneis; abdoraine nigricante; cephalo- thoracis 

 parte anteriori promineute obtusa utrinque indentata. 



Length of the male xB^th of an inch ; length of cephalo-thorax -^ ; breadth -^ -, 

 breadth of abdomen -^ ; length of an anterior leg ^ ; length of a leg of 

 the third pair ^j. 



Cephalo-thorax oval, convex above, glossy, prominent, but obtuse, in front, 

 with a slight indentation in the medial line of the posterior region, and 

 another immediately behind each lateral pair of eyes. Mandibles conical, 

 armed with teeth on the inner surface, and inclined towards the sternum, 

 which is broad and heart-shaped. These parts, with the maxillae, lip, 

 legs, and palpi, are brown, the lip being the dailiest, and the legs the 

 lightest coloured. First and fourth pairs of legs, which are the longest, 

 equal in length, third pair the shortest. Third and fourth joints of the 

 palpi short, the latter being much the stronger; fifth joint somewhat oval, 

 having a projection on the outer side ; it is convex and hairy externally, 

 concave within, comprising the palpal organs, which are highly developed, 

 complicated in structure, with a slender, corneous process at the superior 

 part, directed upwards, a bold prominence on the inner side, and a fine, 

 convoluted, filiform spine, enveloped in a delicate membrane, extending 

 from the upper part of the extremity ; their colour is red-brown. Abdo- 

 men oviform, thinly covered with hairs, convex above, projecting over the 

 base of the cephalo-thorax ; it is of a brownish black colour. Plates of 

 the spiracles pale yellow. 



Males of this species, with the palpal organs fully developed, were taken in 

 July 1836, on rails near Llanrwst. 



22. fValchenaera parva. Brunnea, abdomine saturatiore ; maris cephalo-tho- 

 race antic^ parilm prominente utrinque indentato. 



Length of the female xjth of an inch ; length of cephalo-thorax -g^ ; breadth 

 -^ ; breadth of abdomen ^ ; length of an anterior leg ^g- ; length of a 

 leg of the third pair ^o- 



Cephalo-thorax oval, glossy, very convex behind the eyes, depressed in the 

 VOL. xvm. 4 o 



