F. P. SMITH OX SOME BRITISH SPIDERS TAKEN IN 1908. 325 



organs, much in the same way as a blind or nearly blind man 

 has the advantage of his fellows during a dense fog. This being 

 so, the application of the generally accepted evolutionary theories 

 would naturally bring us to the present state of things — the 

 survival of the Porrhommae. No doubt as time goes on the eyes 

 of these little mine-dwellers will become more and more vestigial, 

 turning to mere pigment patches, and finally disappearing 

 altogether. It is stated on excellent authority that the Porrhommae 

 in the coal-mines live together in colonies, and it is not impos- 

 sible that they find this advantageous in dealing with large and 

 troublesome victims. A small Eresid from South Africa has 

 highly-developed social habits, large numbers of individuals 

 spinning a common web and killing unwieldy victims by con- 

 certed attack. By the kindness of Mr. R. Hancock, of Stechford, 

 I had an opportunity of keeping a colony of these remarkable 

 spiders for a considerable time, and was greatly struck by their 

 curious habits. I at once thought of the accounts of the coal- 

 mine Porrhommae, and wondered whether their habits were in 

 any way similar. Opportunity, however, has not yet arrived for 

 personal investigation of the matter. 



Centromeria tricolor typica (131.), 1833. 



1833. Neriene bicolor, Bl., Lond. Ed in. Phil. Mag. 



1834. IAnyphia comata, Wid., Zool. Misc. 

 18G4. Neriene bicolor, Bl., Spid. G. IJ. I. 

 1879. ,, ,, Camb., Spid. Dorset. 



1900. Tmeticus ,, ,, List Brit. Irish Spid. 



Centromeria bicolor concinna (Thor.), 1875. 



1900. Tmeticus concinnus, Camb., List Brit. Irish Sjnd. 



Specimens of this species occurred in several localities near 

 London, and opportunities have also arisen for the examination 

 of series taken in the north of England. To my mind the form 

 concinna ought to be regarded as a sub-species of bicolor. The 

 paracymbium of the male palpus certainly exhibits a very 

 considerable difference if compared in a typical example of each 

 form ; but intermediate types are of frecpient occurrence, which 

 would seem to preclude our regarding the two as specifically 

 distinct. Well-defined females differ in size, in the armature of 



