The Orthoptera Species File (OSF) is a taxonomic database of the world's orthopteroid insects. It contains full synonymic and taxonomic information for over 25,000 species and genera of the Tettigonioidea (katydids and haglids), Grylloidea (crickets), Acridomorpha (locusts and grasshoppers: Acridoidea + Eumastacoidea + Trigonopterygoidea + Pneumoroidea + Pamphagoidea), Tetrigoidea (pygmy grasshoppers), Tridactyloidea (sand crickets), and Gryllacridoidea (camel crickets, Jerusalem crickets and the allies), as well as images and sounds for many species. The web site also includes a searchable database of entomologists working on the Orthoptera.