The group of Arachnida which includes the mites and ticks. Many species are parasitic, and cause diseases like the itch and mange.

Acarina or Acari are a taxon of arachnids that contains mites and ticks. The diversity of the Acari is extraordinary and its fossil history goes back to the Devonian. As a result, acarologists (the people who study mites and ticks) have proposed a complex set of taxonomic ranks to classify mites.