The genus Ophiogomphus Lieftinck, 1964 in Vietnam, with descriptions of the female of O. minimus Karube, 2014 and O. phantoani sp. nov. (Odonata: Gomphidae).

Description of Ophiogomphus phantoani sp. nov. (Holotype ♂: Dak Re Commune, Song Thanh National Park, Quang Nam Province, central Vietnam, 15.5080 N, 107.4720 E, altitude 1105 m) is based on both sexes. Three other species of Ophiogomphus in Vietnam are recorded with description of the female O. minimus Karube, 2014 for the first time. Keys to males and females of four species from Vietnam are also provided.

A review of the Drepanosticta carmichaeli-group, with the description of D. wildermuthi sp. nov. from the Central Highlands of Vietnam (Odonata: Zygoptera: Platystictidae).

A modified and expanded definition of the Drepanosticta carmichaeli-group is given. This includes the species: D. annandalei Fraser, 1924, D. brownelli Tinkham, 1938, D. carmichaeli (Laidlaw, 1915), D. emtrai Dow, Kompier Phan, 2018, D. hongkongensis Wilson, 1997, D. jurzitzai Hmlinen, 1999, D. sumatrana Sasamoto Karube, 2007, D. tenella Lieftinck, 1935, D. vietnamica Asahina, 1997 and D. wildermuthi sp. nov.). The species of the group are reviewed and in most cases illustrated, diagnostic notes are given wherever possible. Drepanosticta polychromatica Fraser, 1931 is considered to be a junior synonym of D. carmichaeli and variation in D. carmichaeli is discussed. Drepanosticta wildermuthi sp. nov. from the Central Highlands of Vietnam (holotype male from Bao Loc district, Lam Dong Province) is described. The female of D. jurzitzai Hmlinen, 1999 is described for the first time. A key to the males of the Drepanosticta carmichaeli-group is provided.

Description of Coeliccia lephuocdieui sp. nov. from the Central Highlands of Vietnam (Odonata: Zygoptera: Platycnemididae) with notes on its congeners.

Coeliccia lephuocdieui sp. nov. (holotype ♂, 14.2586N, 108.3786E, Kon Ka Kinh National Park in Ayun Commune, Mang Yang District, Gia Lai Province, the Central Highlands of Vietnam) is described and illustrated for both sexes. A comparison of the new species with Coeliccia scutellum Laidlaw, 1932 and C. yamasakii Asahina, 1984 is provided with notes on the morphological variation of the Vietnamese C. scutellum. The female of C. yamasakii is described for the first time.

Description of Coeliccia natgeo sp. nov. from Central Vietnam with keys to the males and females of the hayashii-group (Odonata: Zygoptera: Platycnemididae).

Coeliccia natgeo sp. nov. is described from central Vietnam (holotype ♂, 18.2708 N, 105.3431 E, Khe Nhop, Vu Quang National Park, Ha Tinh Province, deposited in the Zoological Collection of Duy Tan University, Da Nang City, Vietnam). The new species differs from other members of the hayashii-group by males lacking antehumeral stripes, spots and pruinosity on the synthorax and female having the central part of the posterior pronotal lobe reduced to a small projection. Keys to the males and females of the hayashii-group are provided.