666 Mr. Blackwall's Descriptions of new Species of Spiders, 



loped, and very complicated in structure, having on the outer side of the 

 upper part a curved, corneous process, bifurcated at the extremity, an 

 obtuse, glossy prominence lower down, and a long, acute spine directed 

 downwards and outwards ; they are of a dark red-brown colour. Abdo- 

 men oviform, convex above, projecting over the base of the cephalo- 

 thorax ; it is thinly clad with hairs, glossy, and brownish black. Plates 

 of the spiracles dark brown. 



Adult males of this species were taken in June 1836, on rails at Oakland. 



49. Linyphia gracilis. Mas nigricans ; mandibulis maxillis pedibus palpisque 

 brunneis paululilm rufo tinctis. 



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

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

 of the third pair -^. 



Anterior part of the cephalo-thorax compressed ; sides marked with furrows 

 diverging from the upper part to the margins ; in the medial line of the 

 posterior region there is a large indentation. Mandibles conical, armed 

 with a few teeth on the inner surface, and inclined towards the sternum, 

 which is heart-shaped, convex, glossy, and provided with some scattered 

 hairs. Maxillse strong, enlarged at the base, where the palpi are inserted, 

 and slightly inclined towards the lip, which is semicii-cular and prominent 

 at the extremity. The cephalo-thorax, sternum, and lip are brownish 

 black, and the mandibles and maxillee brown, faintly tinged with red. 

 The posterior eyes of the trapezoid are the largest, and the anterior ones 

 much the smallest of the eight. Legs long, slender, and pale brown, 

 tinged with red. The palpi are short, and resemble the legs in colour, 

 with the exception of the terminal joint, which is darker; fourth joint 

 much stronger than the third ; fifth oval, convex and hairy externally, 

 concave within, comprising the palpal organs, which are prominent, 

 highly developed, complicated in structure, with a small, glossy protu- 

 berance on the outer side of the upper part, and a fine spine at the ex- 

 tremity, enveloped in a delicate membrane, and curved into a circular 

 form ; they are of a red-brown colour. The convex sides of the terminal 

 joints are directed towards each other. Abdomen oviform, convex above. 



