134 HARVEST-SPIDERS 



The size of the body varies from about 1 to 20 mm in length, but 

 the majority are between 5 and 10 mm long. 



The Opiliones are divided into three sub-orders, of which the 

 Cyphophthalmi is the most primitive. It comprises some forty 

 mite-like species varying in length between 1 and 3 mm, with 

 short legs and repugnatorial glands opening at the ends of lateral 

 prosomatic tubercles. The genitalia are not covered by an oper- 

 culum but the body is protected by a shield resulting from the 

 fusion of the cephalothorax and the abdominal tergites, excepting 

 the last. The abdominal sternites are also fused in a similar manner 

 and eyes are often absent. 



The Cyphophthalmi have a very discontinuous distribution, 

 species occurring in Corsica, Dalmatia, central France, parts of 

 tropical Africa, Ceylon, Japan, the East Indies and the United 

 States of Florida and Oregon. They are generally to be found in 

 humid situations under more or less deeply buried stones. The 

 genus Siro is represented in France by S. rubenSy a species first dis- 

 covered by Latreille at Brive and long mistaken for a mite until 

 E. Simon established its true nature. Siro duricorius is known from 

 the caves of Carniola in Yugoslavia and the related Parasiro cor- 

 stcus from the neighbourhood of Porto Vecchio in Corsica. The 

 genus Stylocellus occurs in the East Indies, Ogivea and Paragovia 

 in Equatorial Africa and Purcellia on the Cape of Good Hope, 

 where the genus Speleosiro is represented by a single troglodytic 

 species. 



The second sub-order, the Laniatores, is more important than 

 the preceding one and some 1,500 species have so far been de- 

 scribed, principally from southern latitudes. They are character- 

 ised by great development of the pedipalps which are armed with 

 stout spines and strong claws and are used as raptatory organs for 

 the capture of prey. The Laniatores have an almost exclusively 

 tropical distribution, one family, the Phalangodidae, having a few 

 representatives in Europe {Scotolemon spp.) and in North America 

 {Phalangodes spp.). These are troglodytes inhabiting, amongst 

 others, the Mammoth Cave in Kentucky. In addition, several 

 genera occur in the tropics of the Old World, Australia, the Pacific 

 islands and most of South America. The remaining families of 

 Laniatores are entirely tropical: the Oncopodidae are found in 



