The arachnology collection at the South Australian Museum contains around 300,000 specimens in these groups as well as many centipedes and millipedes (Myriapoda).
Spider specimens make up the largest component, with some 200,000 specimens stored in alcohol. The Sparassidae (huntsman spiders) are particularly well represented in the collection with over 2000 Australasian specimens.
The collection also houses a significant mite (Acarina) collection (about 45,000 specimens) in alcohol or on glass microscope slides, approximately 5000 scorpion (Scorpiones) specimens and a smaller number of Myriapoda specimens (about 3600).
The mite collection is internationally renowned due to the work of the prominent acarologists Herbert Womersley, Ron Southcott, and David Lee who researched mites from Australia and from overseas. Robert Domrow (Queensland Museum) also vastly improved the collection of parasitic mites from vertebrates. The specimens they collected are constantly referred to by acarologists around the world.
All glass slides are stored in a new purpose-built modern slide storage facility while spirit material is stored in the specially designed invertebrate spirit store.