Key to species of Nicolaus Lindberg from the Indian subcontinent

1. Vertex of head with anterior submarginal brown stripe between eyes (Figs 1, 3, 9, 21)............................... 2

- Vertex of head without submarginal brown stripe between eyes, may have brown patches (Figs 5, 41)... N. cornutus sp. nov.

2. Aedeagal shaft anteriorly sclerotized medially (Figs 35, 56); apophysis of style slender, without toothed pigmented border (Figs 34, 53)......................................................................................... 3

- Aedeagal shaft membranous (Figs 17, 25); apophysis of style stouter with toothed pigmented border (Figs15, 23)......... 4

3. Preatrial processes of aedeagus enlarged and strongly serrated subapically on ventral margin (Fig. 56)... N. serratus sp. nov.

- Preatrial processes of aedeagus expanded apically with pair of prominent denticles on ventral margin (Figs 36, 37).......................................................................................... N. bihamatus Xing & Li

4. Preatrial processes of aedeagus with pair of prominent denticles on ventral margin (Figs 24, 25)...... N. bidentatus sp. nov.

- Preatrial processes of aedeagus without prominent denticles on ventral margin (Figs 17, 18)........... N. abuensis sp. nov.