Class Arachnida Lamarck, 1801
   Subclass Acari Leach, 1817 - mites and ticks
     Superorder Parasitiformes Reuter, 1909 - ticks and ticklike mites
       1 Order Opilioacarida Zakhvatkin, 1952
       2 Order Holothyrida Thon, 1905 - holothyrans
       3 Order Ixodida Leach, 1815 - ticks
       4 Order Mesostigmata Canestrini, 1891