Key to species of Mahellus

1. Subgenital plate with posterior spine-like projection (Fig. 44).................................... .. ungulatus sp. nov.

- Subgenital plate without posterior spine-like projection (Figs 21, 36; Nielson 1982: Figs 260, 267).....................2

2. Pygofer ventral process short, glabrous (Fig. 18); aedeagal shaft robust, tapered apically with lateral processes broad and spinose (Figs 22–24)....................................................................... distanti Nielson

- Pygofer ventral process with dentate ventral margin (Figs 33, 41; Nielson 1982: Fig. 263); aedeagal shaft narrow, with thinner processes (Figs 37, 45; Nielson 1982: Fig. 261)..............................................................3

3. Subgenital plate truncate apically (Nielson 1982: Fig. 260); style with apophysis not produced into a thin process but narrowed (Nielson 1982: Fig. 259)............................................................... determinatus (Distant)

- Subgenital plate rounded apically (Fig. 36); style with apophysis abruptly narrowed and produced into a thin process (Fig. 35)...................................................................................... ... cardoni sp. nov.