neio and obscure British Spiders. 389 



It forms another most interesting addition to the British 

 arachnological fauna. 



Notes on rare British Spiders, loith Characters of some 

 obscure and closely-allied Species. 



Dictynidse. 



Amaurobius fenestralis, Stroem. 



,, similis, Blk. 



(PI. XXI. figs. 10, n,a,b,c.) 



These two species occur in abundance in Cumberland and 

 throughout the Lake districts. A. fenestralis is very common 

 under stones and in the stone walls all over the fells near 

 Carlisle, and may be always recognized by its smaller size. 



The male may further be distinguished from similis by the 

 straightness of the spur on the inner anterior angle of the 

 radial joint. 



Tiie dark blotcli on the anterior part of the abdomen is 

 seldom or never divided as it is most frequently in similis 

 (PI. XXI. figs. 10, 11, a). 



The females are not so easy to distinguisli ; but an exami- 

 nation of the epigyne will form a good, though I can scarcely 

 aflSrm a certain, clue. There appears to be a want of 

 stability in this portion of the female structure (PI. XXI. 

 figs. 10, U,b). PI. XXI. fig. 11, c, exhibits the nest of 

 A. fenestralis, formed, between two stones, of bits of dry 

 moss, insect debris, wings, legs, &c., while the female may 

 be observed crouching beside her egg-sac in the centre. 



This little species is never, so far as I am aware, found in 

 outhouses or other buildings, nor have I ever taken it in very 

 close proximity to buildings, though doubtless it will occur 

 in the walls around farm buildings on the fells, where every 

 wall contains numbers of specimens. 



A. similis, on the other iiand, is found abundantly, though 

 not exclusively, in outhouses, stables, &c. There is scarcely 

 a crevice in any garden-wall, paling, ])aHisade, which nuiy 

 not be tenanted by this ubiquitous spicier. fiiey are, how- 

 ever, also abundant in the fissures of the Red-8andstone cliffs 

 overhanging the streams, and in the quarries around 

 Carlisle. 



The males of this species may be recognized by the fact 

 that the spur at the inner anterior angle of the radial joint is 

 abruptly narrowed, its apex aculeate and much curved 

 inwards and upwards towards the palpal organs. 



For figures of the epigyne see PL XXL figs. 10, 11, b, c. 



