Subclass Acari Leach, 1817 - mites and ticks Superorder Parasitiformes Reuter, 1909 - ticks and ticklike mites A Order Opilioacarida Zakhvatkin, 1952 [monotypic] B Order Holothyrida Thon, 1905 [monotypic] - holothyrans C Order Ixodida Leach, 1815 [monotypic] - ticks D Order Mesostigmata Canestrini, 1891