Aim Based on seven consecutive seasons of biotic survey and inventory of the terrestrial and freshwater plants and animals of the 30 major islands of the Kuril Archipelago, a description of the biodiversity and an analysis of the biogeography of this previously little known part of the world are provided.Location The Kuril Archipelago, a natural laboratory for investigations into the origin, subsequent evolution, and long-term maintenance of insular populations, forms the eastern boundary of the Okhotsk Sea, extending 1200 km between Hokkaido, Japan, and the Kamchatka Peninsula of Russia. A chain of more than 56 islands, the system is only slightly smaller than the Hawaiian Islands, covering an area of 15,600 km 2 and providing 2409 km of coastline.Methods Collections of whole specimens of plants and animals, as well as tissue samples for future molecular studies, were made by teams of scientists from Russia, Japan, and the USA, averaging 34 people for each of the seven annual summer expeditions (1994)(1995)(1996)(1997)(1998)(1999)(2000). Floral and faunal similarities between islands were evaluated by using Sorensen's coefficient of similarity. The similarity matrix resulting from pair-wise calculations was then subjected to UPGMA cluster analysis.

A new subgenus, 19 new species and two new subspecies are described from Vietnam, Laos and China: Tamdaotettix (Tamdaotettix) aculeatus sp. nov., T. (T.) flexus sp. nov., T. (T.) laocai sp. nov., T. (Laotettix subgen. nov.) tarasovi sp. nov., T. (L.) curvatus sp. nov., T. (L.) minutus sp. nov., T. (L.) inflatus sp. nov., T. (L.) sympatricus sp. nov., T. (?) robustus sp. nov., Gigantettix laosensis sp. nov., G. maximus auster subsp. nov., Diestramima hainanensis sp. nov., D. bispinosa sp. nov., D. hamata sp. nov., D. propria sp. nov., D. yunnanensis sp. nov., D. champasak sp. nov., Adiestramima adunca sp. nov., A. bella sp. nov., A. elongata sp. nov., A. perfecta hue subsp. nov. Previously unknown male of G. maximus maximus Gorochov, 1998 and imago of D. palpata (Rehn, 1906) are described on the base of a new material. New distributional data for some species are given.

The genera Megadiestramima Stor. et Gor. and Mimadiestra Stor. et Dawwrueng are considered. Megadiestramima is here divided into three subgenera: Megadiestramima s. str.; Leodiestramima Stor. (in 2014, this subgenus was raised up to generic rank by Storozhenko & Dawwrueng, but in 2015, it was restored in original subgeneric rank by Gorochov & Storozhenko); Neodiestramima subgen. nov. Seven new species and subspecies of this genus are described from Vietnam, Thailand and Cambodia: M. (M.) borealis sp. nov.; M. (M.) abramovi sp. nov.; M. (M.) bilobata sp. nov.; M. (M.) centralis sp. nov.; M. (N.) orlovi lata subsp. nov.; M. (N.) o. khmerica subsp. nov.; M. (N.) brevispina sp. nov. Keys to subgenera and species of Megadiestramima s. l. and Mimadiestra as well as keys to subgenera of Diestramima Stor. and Adiestramima Gor. are given. Eight additional new taxa of the latter genera and of the genus Tamdaotettix Gor. are described from Laos, China and Vietnam: Baculitettix subgen. nov. and Excisotettix subgen. nov. in Diestramima s. l.; D. (B.) propria apicalis subsp. nov.; Hamatotettix subgen. nov. and Ulterotettix subgen. nov. in Adiestramima s. l.; A. (Adiestramima) originalis sp. nov.; T. (Tamdaotettix) ailaoshanicus sp. nov.; T. (T.) minipullus sp. nov. New data on distribution of some species are also given.

An annotated list of 39 species in 25 genera and seven subfamilies of the pygmy grasshoppers (Orthoptera: Tetrididae) from Thailand is given; from these 18 species are recorded from this country for the first time. Five new species are described: Cotysoides gaponi sp. nov. (subfamily Metrodorinae), Eucriotettix anisyutkini sp. nov., Gavialidium bufocrocodil sp. nov., Scelimena bellula sp. nov. (subfamily Scelimeninae) and Phaesticus uvarovi sp. nov. (subfamily Discotettiginae). One species is transferred from Scelimena to Amphibotettix and a new combination is proposed: Scelimena hafizhaii Mahmmod, Idris et Salman, 2007 = Amphibotettix hafizhaii (Mahmmod, Idris et Salman, 2007), comb. nov. The previously unknown male of Falconius tschernovi Storozhenko, 2014 is described.

The pygmy grasshopper subfamily Batrachideinae consists of three tribes: Batrachideini Bolívar, 1887; Cassitettigini Yin, 1984, nom. resurr.; Bufonidini Hancock, 1907, nom. resurr., stat. nov. The Australian pygmy grasshoppers of the tribe Bufonidini are reviewed. Three new genera are described, namely Paraselina gen. nov. (type species Vingselina multifora Rehn, 1952), Anaselina gen. nov. (type species Vingselina minor Sjöstedt, 1921), and Selivinga gen. nov. (type species Selivinga tribulata sp. nov.). Four new combinations are proposed: Paraselina multifora (Rehn, 1952), comb. nov.; P. trituberculata (Sjöstedt, 1932), comb. nov.; P. brunneri (Bolívar, 1887), comb. nov.; Anaselina minor (Sjöstedt, 1921), comb. nov. A key to Australian genera of Batrachideinae is provided.