The Grassatores are the most diverse infraorder of the Laniatores. It includes over 3,500 species distributed mainly in the tropics They are characterized by the male genitalia without musculature, operated by hydraulic pressure and by the double tarsal claws of posterior legs. Superfamilies Assamioidea Sørensen, 1886 Phalangodoidea Simon, 1879 Samooidea Sørensen, 1886 Zalmoxoidea Sørensen, 1886 Gonyleptoidea Sundevall, 1833 References External links Classification of Opiliones A synoptic taxonomic arrangement of the order Opiliones, down to family-group level, including some photos of the families Harvestmen