HARVEST-SPIDERS 135 



India, the Assamiidae in India, and other parts of Asia and Africa 

 excluding Madagascar, the Cosmetidae in the southern United 

 States and the Triaeonychidae in Madagascar, Australia and 

 America. The largest family is the Gonyleptidae which is almost 

 entirely confined to South America where species live in damp 

 forests under stones and fallen trees. They have particularly large, 

 defensive spines on the last pair of legs. 



The most important sub-order of the Opiliones is the Palpa- 

 tores, to which all the British species belong. Four families are 

 known, of which the Trogulidae are considered to be the most 

 primitive. These are sluggish, short-legged, ground-living species 

 to be found among grass roots, moss and even mud in chalky dis- 

 tricts of Europe, Asia Minor, North Africa and North America. 

 The fore edge of the prosoma forms a bifurcated hood covering the 

 mouth parts, there is no ocular tubercle and the body is dark 

 coloured and habitually covered with particles of dirt and earth 

 which render the animals extremely difficult to see. The Nemas- 

 tomidae are also small, short-legged, dark, ground-living forms 

 usually found among moss and dead leaves while the Ischyropsal- 

 idae are a small family limited to central Europe, where they live in 

 damp moss in woods, mountain torrents and the caves of the Pyre- 

 nees. The largest family is the Phalangiidae which includes all the 

 well-known long-legged harvestmen of Europe, North Africa and. 

 North America. These animals have typically rounded bodies, the 

 palpal tarsus is longer than the tibia and its claw is well developed. 

 They are to be found among litter and fallen leaves on the ground, 

 on the trunks of trees and in vegetation (Todd, 1949). 



The distribution of harvest-spiders in the British Isles has been 

 described by Bristowe (1949) and Sankey (1949b), while the Euro- 

 pean forms have been studied by Stipperberger (1928). 



General behaviour 



The name Opilio means, in Latin, a 'shepherd' and may refer to 

 the fact that in some countries shepherds walk about on stilts, the 

 better to count their flocks. In our own land harvestmen were 

 known as 'shepherd spiders' four centuries ago, but T. Muff'ett 

 (1634) in his Theatre of Insects'f explained this by saying 'the 



t Insectorum sive minimorum animaliiim theatrum. London. 



