THOMISIDAE 



413 



are much smaller and darker. It is common in some parts of 

 England, especially in the south, where it is to be sought for in 

 bushes and trees. 



Biaea dorsata is one of our prettiest British species, with light 

 green legs and cephalothorax, 

 and a yellow abdomen with a 

 red -brown central marking. 

 It is common in the New 

 Forest and other southern 

 localities. The female attains 

 a quarter of an inch in 

 length. 



Thomisus onustus, a rare 

 spider among heather, is recog- 

 nisable by the shape of its 

 abdomen, which is broadest 

 behind and abruptly truncated. 

 When adult the abdomen is a 

 pale yellow, but the young are 

 suffused with a pink hue closely 

 corresponding with that of tlie 

 heather blossom in which tliey 

 are frequently found sitting. 



(ii.) The Philodhominae 

 have the cephalothorax more 

 rounded in front, and the 

 legs, especially the second pair, 

 usually longer than in the 

 Thomisinae. There are ten 

 genera, of which the most 



important is Philodromus, which numbers about a hundred species. 

 They are active spiders, living upon bushes and trees, and most 

 of them are inhabitants of temperate regions. We have about 

 twelve species in the British Isles. The commonest is Ph. aureolus, 

 which is abundant on bushes in most parts of the country. 

 Some species are very prettily marked, and one. Ph. margaritatus 

 (Fig. 213, C) presents a very good example of protective colora- 

 tion, being almost indistinguishable on the blue-grey lichen on 

 tree trunks, where it lies in wait for insects. 



Another important genus, including some fifty species, is 



Fig. 213. — Thomisid spiders. A, Micrommata 

 virescens, 9 ; B, Xysticii.s pini, 9 ; C, 

 Fhilodromns margaritatus, 6 ; D, TibeUus 

 oblong us, 9 . 



