634 Mr. Bzackwazvs Descriptions of new Species of Spiders. 
20. Walckenaëra bifrons. Mas saturaté brunneus ; pedibus palpisque flaves- 
centi-rufis ; cephalo-thorace anticé protuberantià magna perpendiculari 
obtusa longitudinaliter biloba. 
Length of the male Arth of an inch; length of cephalo-thorax A; breadth 4 ; 
breadth of abdomen g; length of an anterior leg +; length of a leg of 
the third pair P- 
On the anterior part of the cephalo-thorax, which is compressed, there is a 
large, perpendicular, obtuse eminence, divided into two lobes at the sum- 
mit by a longitudinal furrow ; the posterior region is depressed, and the 
frontal margin very prominent. Mandibles small, 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 dark 
brown, the lip and frontal eminence of the cephalo-thorax being the 
darkest. Legs and palpi yellowish red. First and fourth pairs of legs, 
which are the longest, equal in length, third pair the shortest. Four eyes, 
situated on the anterior part of the frontal eminence, form a square; the 
two superior ones are seated on a minute tubercle, and the inferior ones 
are the smallest of the eight; the other four are disposed in pairs on the 
sides of the eminence, near the front, those of each pair being contiguous. 
The fourth joint of the palpi, which is much shorter than the third, pro- 
jects a small, slightly curved apophysis from its anterior extremity, on the 
outer side; the fifth joint is oval, convex and hairy externally, with an 
indentation on the outer side of the upper part; it is concave within, 
comprising the palpal organs, which are highly developed, complicated in 
structure, with a curved, black spine at the extremity, enveloped in a de- 
licate membrane, and are of a reddish brown colour. Abdomen oviform, 
convex above, projecting over the base of the cephalo-thorax ; it is thinly 
covered with hairs, glossy, and dark brown. Plates of the spiracles dull 
yellow. 
The spider described above was captured by T. Glover, Esq., of Smedley, 
near Manchester, in June 1838, among coarse herbage in Gwydir woods, near 
Bettws y Coed, Caernarvonshire. 
