Class Arachnida Lamarck, 1801
   Subclass Arachnina
     01 Order Araneae Clerck, 1757 - spiders
     02 Order Amblypygi Thorell, 1883 - whip spiders
     03 Order †Architarbi see Order Phalangiotarbida Haase, 1890
     04 Order †Haptopodida see Order Haptopoda Pocock, 1911
     05 Order Opiliones Sundevall, 1833 - harvestmen
     06 Order Palpigradi Thorell, 1888 - palpigrades
     07 Order Pseudoscorpionida Latreille, 1817 - false scorpions see Order Pseudoscorpiones De Geer, 1778
     08 Order Ricinulei Thorell, 1876 - ricinuleids
     09 Order Schizomida Petrunkevitch, 1945 - schizomids
     10 Order Scorpiones Koch, 1837 - scorpions
     11 Order Solifugae Sundevall, 1833
     12 Order †Trigonotarbida Petrunkevitch, 1949
     13 Order Uropygi Thorell, 1882 - whip scorpions see [unranked] Uropygi Thorell, 1882