BRITISH SPIDERS OF THE GENUS MICRONETA 121 



forward. It then turns through an angle of 90 , so that its 

 anterior end tends to look directly upwards. 



The lamella characteristica consists of a wider body and a 

 narrower tapering tail which runs to the posterior end of the 

 palpal organs, between those organs and the inner side of the 

 paracymbium. In each species it exhibits a slight range of 

 variation, but as far as my present experience goes is always 

 easily recognizable. This is the more fortunate, as in these 

 spiders the paracymbium does not yield good, specific char- 

 acters. It does vary in the different species, but the differences 

 are so slight and the organ appears so very different in different 

 positions that it is very difficult to make use of it in the identi- 

 fication of the various species. 



Characters drawn from the height of the clypeus and that 

 of the ocular area, and from the exact shape of the profile of 

 the cephalothorax, are so variable that with one or two 

 exceptions they are quite useless in providing specific 

 distinctions. This applies to the females as well as the 

 males. In the former sex the chief specific characters must 

 be drawn from the structure of the epigyne. Careful examina- 

 tion of this organ will in the majority of the cases lead to 

 fairly easy recognition of the species. With the Micronetoids 

 divided into four genera, the generic and vulvar char- 

 acters work out between them a fairly reliable diagnosis. 

 Occasionally however specimens do occur of which it is 

 impossible to be absolutely certain. With practice these are 

 very infrequent, and they are certainly not more numerous 

 than in several of the other allied genera. 



As regards the nomenclature used in this paper, I have not 

 ventured amongst the nice questions of ancient history. I 

 have accepted the names used by Mr. Pickard-Cambridge in 

 his " List of British and Irish Spiders," and have not repeated 

 in my synonymic lists all the names which he had already 

 discarded in 1900. All the changes in nomenclature which I 

 have made have been the result of the examination of such 

 actual specific types as I had at my disposal. 



