152 SPIDERS 



tubular nests open at both ends, in rolled leaves or under bark. 

 Some also live among vegetable debris and nest under stones. The 

 Clubionidae that habitually live on the soil exhibit far more 

 diversity in size, appearance and coloration than do the conserva- 

 tive plant-dwelling forms. Many smaller species such as the British 

 Phrurolithus festivus are myrmecophilous and mimic ants. 



Crab spiders or Thomisidae are sedentary animals that wait on 

 the ground or in flowers and vegetation for passing insects which 

 are seized by the powerful outstretched legs: they frequently 

 possess markedly cryptic (conceaHng) coloration. The English 

 name for this family derives from their habit of running sideways 

 like crabs. The Salticidae or jumping spiders are small, rather 

 squat animals with broad square heads, extremely large eyes and 

 short, stout legs. They have very keen sight and stalk their prey 

 from afar. This is one of the largest spider families and includes 

 several thousand species which are found mainly in tropical 

 countries where they almost rival the insects in the brilliance of 

 their hues. Only thirty-two species are on the British list and most 

 of these are rare and unlikely to be found, except by the most 

 energetic collector. Our commonest species is the little 'zebra 

 spider', Salticus scenicus, so named because it is conspicuously 

 marked with black and white stripes. Though less brilliantly 

 coloured than some of its exotic relatives, it is an attractive creature 

 often to be seen walking on walls and fences in the sunshine. 



Wolf spiders of the family Lycosidae have longer bodies and 

 hmbs and moderately large eyes and overcome their prey by sheer 

 strength. Like the related Pisauridae, they are essentially ground- 

 living forms and the majority of them hunt in the open by day. 

 Two other families of hunting spiders, the Oxyopidae and the 

 laterigrade Sparassidae, contain species which are usually found in 

 low herbage whence they leap down on to their unsuspecting prey. 

 They are represented in the British fauna by Oxyopes hetero- 

 phthalmus and Micrommata virescens, respectively, and are more 

 numerous in the warmer regions of the world where the giant 

 crab spider, Heteropoda venatoria, is widely distributed. 



The remaining families are all web-builders, the Agelenidae 

 constructing funnel-shaped cobwebs consisting of a triangular 

 sheet with its apex rolled into a tube in which the spider waits for 



