328 F. P. SMITH ON SOME BRITISH SPIDERS TAKEN IN 1908. 



as an absolute criterion of specific identity forbids the systematist 

 from regarding these two forms as anything more than varieties. 

 The whole subject, however, from this aspect is an exceedingly 

 involved one, and a very considerable time is likely to elapse 

 ere the various workers will have brought their systems into 

 something like uniformity. 



Lessertia, n.g. 



General characters as in the " Tmeticus " group. 



Both sexes. — Posterior eyes about equidistant. Anterior 

 laterals hardly larger than posterior centrals. Femora without 

 spines above. Tibiae with strong spines above, two each on 

 i., ii. and in., one on iv. No metatarsal spines. Sternum 

 considerably longer than broad, produced in an almost parallel- 

 sided elongation between the hind coxae. Falces with well- 

 marked lateral transverse striae (? stridulatory). 



Male only. — Maxillae strongly conical near the middle of the 

 under surface. Palpal tarsus at least as long as tibia, which is 

 considerably longer than patella ; palpal tarsus broader than 

 tibia, which is broader than patella. 



Type, Lessertia simplex (F. Camb.), 1892. 



In the breaking up of the heterogeneous group of spiders 

 included under the name Tmeticus, the species simplex seeming 

 to possess characters sufficiently distinct to justify its being 

 regarded as the type of a separate genus, I propose the generic 

 title Lessertia* This genus is closely allied both to Leptorhop- 

 trum, Kulcz. and to Tmeticus, Menge ; the following table will, 

 however, enable one to separate the three without much difficulty. 



(a) Both sexes. 



(1) Sternum as broad as long. Spines on tibiae extremely 

 minute, shorter than the diameter of the joint. 

 Falces (at least in male) without definite trans- 

 verse striae on outer side .... Tmeticus. 

 Sternum considerably longer than broad, produced in 

 a parallel-sided elongation between the hind coxae. 



A'om.projf., in honour of Mons. Roger de Lessert, who is responsible 

 for some very valuable work in connection with the Araneidea of 

 Switzerland. 



