Arachnida 197 



A brief analysis of the local spider fauna will probably be 

 more useful here than a complete list of species. 



The classification of the Araneae is by no means at present 

 in a crystallised condition, but according to our view thirteen 

 families are represented in the neighbourhood. Five of these, 

 however, account for only eight species. Atypus piceus, 

 mentioned above, is the only example of the Atypidae ; the 

 little brick-red six-eyed spider, Oonaps pulcher, is the sole 

 representative of the Oonopidae ; of the Dysderidae six-eyed 

 spiders of fair size, living under stones or bark the three 

 commoner species are plentiful around Cambridge ; the pretty 

 little Ero furcata is the only member of the Mimetidae, while 

 of the Pisauridae, Pisaura mirabilis is common, and the large 

 and handsome Dolomedes fimbriatus has been recorded. 



The remaining eight families call for a somewhat more 

 extended notice. 



DRASSIDAE. These are elongate flat spiders, living under 

 stones or bark or in curled leaves, or in some cases running 

 freely on the ground. Their colouration is usually dull, the 

 majority being brown or mouse-coloured, and a few jet-black. 

 There are more than twenty local species. The large mouse- 

 coloured spider, so often seen lurking under a stone, is Drassus 

 lapidosus. Clubwna has several species, and the handsome 

 C. corticate, more elaborately marked than most of the group, 

 is common under bark. C. subtilis is very common in the fens, 

 while the rare C. lutescens is taken at Wicken. The jet-black 

 Drassids belong to the genus Melanophora, and Wicken is one 

 of the few localities for M. lutetiana. 



DICTYNIDAE. A small group of " cribellate " spiders, the 

 female possessing an extra spinning organ, the "cribellum," 

 correlated with a comb on the hind leg called " calamistrum." 

 Amaurobius lives in cellars and out-houses, while Dictyna is 

 found among herbage. 



AGELENIDAE. This not very extensive group of sheet- web 

 spiders includes some very familiar examples. The large 

 Tegenaria domestica and the smaller T. derhamii are common 



