Three new species of Oocyclus Sharp, 1882, with additional records from China (Coleoptera, Hydrophilidae, Laccobiini).

Three new species of the water scavenger beetle genus Oocyclus Sharp, 1882 from China (Oocyclusextensus sp. nov., from Xizang, O.latiorificialis sp. nov. and O.ximaensis sp. nov. from Yunnan) are described and illustrated in detail. Additional faunistic data, illustrations of habitus and male genitalia, and a key to Chinese species are provided.

The Asian rock-dwelling antlions Gatzara Navás, 1915 and Nepsalus Navás, 1914 (Neuroptera: Myrmeleontidae): new advancements in systematics, biogeography and life history.

The antlion genera Gatzara and Nepsalus (Myrmeleontidae: Dendroleontinae) inhabit mountain forests and are characterised by camouflaging larvae. Both genera remain poorly known despite recent findings on systematics and distribution. We report the discovery of new specimens and the previously unknown larvae of the rare species Gatzara jubilaea Navás, 1915, Nepsalus insolitus (Walker, 1860) and N. decorosus (Yang, 1988). These provide new evidence regarding the affinities of these species, and updated knowledge of the distribution, larval morphology and biology. Moreover, a new species of Nepsalus , N. maclachlani Badano, Zheng & Liu, sp. nov. is described from Sri Lanka based on historical museum collections. The discovery of the immature stages of Gatzara shows that the larvae of this genus share the same specialised ecological characteristics and habits as those of Nepsalus but are less morphologically derived. We also reconstruct a molecular phylogeny of this lineage, estimating the divergence time and biogeographical history by adding the new samples. The evolution of the Gatzara + Nepsalus lineage is associated with two major mountain ranges on the southern Tibetan Plateau, i.e. the Himalayas and the Hengduan Mountains. ZooBank: urn:lsid:zoobank.org:pub:68E68211-DFC1-4D98-997B-8A23BA8F9B69.

Larval morphology and new records of the iconic diving beetle Acilius sinensis Peschet, 1915 (Coleoptera: Dytiscidae: Dytiscinae)-a species well established in western Yunnan, China.

Adults and larvae of the very rare Chinese endemic species Acilius sinensis Peschet, 1915 are newly reported from three localities in western Yunnan, which indicates the presence of viable populations in this area. Based on the available data, the rarity of the species in collections is more caused by collecting bias than actual threat of its habitat loss. All larval instars of A. sinensis are for the first time described according to the now generalized larval descriptive format of Dytiscidae, which incorporates detailed chaetotaxic and morphometric analyses. Like other known Acilius Leach, 1817 larvae, A. sinensis is characterized by the typical Y-shaped median process of prementum. So far as the third instar larva is considered, A. sinensis shares with A. fraternus (Harris, 1828), A. kishii Nakane 1963, A. semisulcatus Aubé, 1838, and A. sulcatus (Linnaeus, 1758) the median process of prementum invaginated at nearly 75% of its length compared to less than 35% in A. abbreviatus Aubé, 1838, A. duvergeri Gobert, 1874, and A. canaliculatus (Nicolai, 1822). As far as chaetotaxy is concerned, A. sinensis is distinguished by the presence of the primary pore PAo located on the ventral face of the parietal. The habitat of the species is briefly commented. Acilius sinensis is here newly proposed for inclusion in the IUCN red list in the category Vulnerable.

Additional fauna of Coelostoma Brullé, 1835 from China, with re-establishment of Coelostomasulcatum Pu, 1963 as a valid species (Coleoptera, Hydrophilidae, Sphaeridiinae).

Six new species of Coelostoma Brullé, 1835 are described from China: Coelostomabannanicum Mai & Jia, sp. nov., C.dactylopunctum Mai & Jia, sp. nov., C.fortunum Mai & Jia, sp. nov., and C.pseudomartensi Mai & Jia, sp. nov. from Yunnan; C.mixtum Mai & Jia, sp. nov. from Fujian; and C.nankunshanense Mai & Jia, sp. nov. from Guangdong. Coelostomasurkhetensis Hebauer, 2002 is a new record from China (Xizang). Coelostomahuangi Jia, Aston & Fikácek, 2014 is reported from Yunnan, C.hajeki Jia, Aston & Fikácek, 2014 from Hunan, C.jaechi Jia, Lin, Chan, Skale & Fikácek, 2017 from Guangdong, C.turnai Hebauer, 2006 from Fujian, Guizhou and Chongqing, and C.wui Orchymont, 1940 from Shanxi and Zhejiang, all for the first time. Coelostomatranscaspicum Reitter, 1906 is excluded from Chinese fauna. Coelostomasulcatum Pu, 1963 is confirmed as a valid species and its variations of aedeagus are illustrated. The specimens treated as C.wui Orchymont, 1940 by previous authors possibly contain two species. The diversity and habitats of Chinese Coelostoma are discussed. A modified key to the species of Chinese Coelostoma is provided.

A new species of Clypeodytes Rgimbart, 1894 from China (Coleoptera, Dytiscidae: Bidessini).

The diving beetle Clypeodytes limpidus sp. nov. is described from western Yunnan, China. It is the second known species of the genus Clypeodytes Rgimbart, 1894 from China and belongs to the subgenus Hypoclypeus Guignot, 1950. It can be distinguished from C. bufo (Sharp, 1890), the only other Chinese Clypeodytes species, by the shape of the median lobe, the more rounded body and the elytral pattern. A Chinese specimen of C. bufo is illustrated, and the species is recorded for the first time for Laos.

Review of Dactylosternum Wollaston, 1854 from China and Japan (Coleoptera, Hydrophilidae, Sphaeridiinae).

The species of the genus Dactylosternum Wollaston, 1854 occurring in China and Japan are reviewed. Ten species are recognized to occur in China, two of which were also recorded from Japan. Four new species are described from China: Dactylosternum nanlingensis Mai et Jia, sp. nov. (Guangdong, Jiangxi) from fungal hyphae on fallen wood, D. songxiaobini Mai et Jia, sp. nov. (Guangxi) from fallen wood with termites, D. pseudolatum Mai et Jia, sp. nov. (Guangdong, Hubei, Hunan, Jiangxi, Fujian, Hainan, Yunnan) and D. frater Mai et Jia, sp. nov. (Yunnan) from banana trees. Dactylosternum latum (Sharp, 1873) and D. salvazai Orchymont, 1925 are reported for the first time from China, and species recorded previously (D. abdominale (Fabricius, 1792), D. corbetti Balfour-Browne, 1942, D. hydrophiloides (MacLeay, 1825) and D. pui Jia, 2002) are redescribed or diagnosed. Dactylosternum abdominale (Fabricius, 1792) is confirmed to occur in Japan. Dactylosternum latum is only known from Japan based on type specimens believed to be collected in Nagasaki by G. Lewis in late 19th century; since the species was never re-collected in Japan later, its distribution in Japan seems doubtful. Dactylosternum vitalisi Orchymont, 1925 is synonymized with D. latum (Sharp, 1873), the variability of the latter species is discussed. We moreover found that the type series of D. vitalisi contains two species, with some paratypes actually belonging to D. pseudolatum Mai et Jia, sp. nov. All species of Dactylosternum living in China and Japan are diagnosed and illustrated and a key allowing their identification is provided. We infer that the compact antennal club and paralleled body form are characters related to the life inside of plant tissues, while loose antennal club and rounded body form is present in free living Dactylosternum species. The combination of characters for distinguishing Dactylosternum from other genera of Coelostomatini is also provided.