Bolitogyrus cyanipennis (Zheng) (A–D), B. kitawakii Smetana & Zheng (E–H), B. nigerrimus Yuan et al. (I–K) and B. metallicus Cai et al. (L–O). Aedeagus in parameral view (A, E), median lobe in lateral view (B, F, I, L), peg setae of paramere (C, G, K, N), apex of median lobe in parameral view (D, H), paramere (J, M), apical half of paramere in lateral view showing median ridge (O). Figures A–D, M–O modified from Cai et al. (2015). Scale bars: 0.5 mm (A, B, D–F, H–J, L, M), 0.1 mm (C, G, K, N).