BRITISH SPIDERS OF THE GENUS MICRONETA II9 



Although I now divide these species into four genera there 

 is nothing novel in this arrangement, as none of the genera 

 are new. The distinctions between the various groups have 

 of course struck others. Kulczynski 1 uses three of the 

 genera, and the other was created by Mr. Hull. 2 There is no 

 doubt however that these spiders are all closely related to 

 each other. In addition to the ordinary characters of their 

 sub-family and group they all show the following positive 

 and regular characters : 



The metatarsi are short, those of the first pair of legs being 

 very distinctly shorter than the tibiae and patellae (taken 

 together) of the same limbs. 



Femoral spines are invariably absent, and except in Syedra 

 metatarsal spines. 



The sexual organs are very characteristic, but it is in the 

 present state of our knowledge difficult to draw hard and fast 

 generic distinctions from them. 



In the female sex the epigyne is very similar in all the 

 species. It consists of a chitinous plate which exhibits on its 

 lower border two sexual apertures separated by a median 

 process. This structure exhibits a little variation in itself, 

 and a good deal in its position. The positional changes 

 probably depend on sexual or maternal activity, and are such 

 that the sexual apertures sometimes look almost directly 

 backwards, and at others almost vertically downwards. In 

 the former cases the whole organ appears somewhat flattened, 

 and in the latter the apertures are as a rule placed at the apex of 

 a prominent downwardly directed epigastric process. These 

 changes take place in all the species, and are probably due to 

 some turgescence of the internal organs, but I am not aware 

 of any research that has been made into the matter, which is 

 not of course peculiar to spiders of this group. It is however 



1 Aranese Hungarian, vol. ii., pp. 84-88. 



2 Trans, of Nat. Hist. Soc. of Northumberland, Durham, and 

 Newcastle-upon-Tyne, new series, vol. iii., part 3, p. 583. 



