1898] THE SMALLEST OF STlilD ULA TING SPIDERS 3 2 1 



spider wliich is provided with so interesting an organ of stridu- 

 lation. 



The spider is an addition to tlic Britannic fauna. It appears to 

 be identical with a species described by Dr L. Koch from the 

 Tyrolese mountains, under the name of Ervjone hrocclia, and sub- 

 sequently discovered near the Great St Bernard by Mr Simon, who ^ 

 placed it in his genus Stijloctetor. In his most recent revision of 

 the spiders of this large and very difficult sub-family (Erigoninae), 

 however, Mr Simon is disposed to reduce the number of genera, and 

 now includes the species of Stylodetor in the large and comprehen- 

 sive genus EntdemraP- We will refer to the spider therefore as 

 Entelecara hroccha (L. Koch). It is evidently a scarce alpine species, 

 but there can be little doubt that it awaits discovery on other hills 

 in our islands. 



Probably the difficulty in determining this, to me, unknown spider 

 led to the discovery of its stridulating organ, on account of the care- 



Fig. 1. 



Fig. 1. Entelecara broccha. — Sternum and front portion of abdomen seen from beneath, 

 showing the basal joints of the legs. The coxa (iv. ) of the fourth pair produced inwardly 

 into sharp spines which play over the ridged surfaces of the lung-book covers (l). 

 Magnified. 



Fig. 2. — Right lung-book cover seen from side, more highly magnified, showing 

 parallel series of coarse ridges with transverse fine ridges (below), and irregular network 

 of fine ridges (above). 



ful examination of its structure which had to be made. When 

 viewing the spider from beneath, the haunches of the fourth pair of 

 legs were seen to differ markedly from those of the other pairs in 

 the possession of a sharp point at the inner hinder angle (fig. 1). 

 Such a sharp point is suggestive of a stridulating organ, but in this 



1 '• Les Arachnides de France." Tome V. Paris, 1884. 



2 "Histoire Naturelle des Araignees." 2me edition. Tome I. Paris 1892. 



Z 



