Vietnamella spp. Vietnamella maculosa sp. nov. (A, D, G, J): A outer projection on head (arrow) D inner and outer projections on head G, J tubercle on tergite VII and X; Vietnamella sp. B (B, E, H, K): B outer projection on head (arrow) E inner and outer projections with serration on head H, K tubercles on tergite VII and X; Vietnamella thani (C, F, I, L): C outer projection on head (arrow) F inner and outer projections on head I, L tubercles on tergite VII and X. Scale bars: 1 mm (A–C); 0.5 mm (G); 0.1 mm (D–F, H, I); 0.05 mm (J–L).