Key to species of Pelodiaetodes from New Zealand based on males

1. Pronotum with distinct sinuation laterobasally and short subparallel basal constriction............................... 2

- Lateral sides of pronotum not sinuate basally, pronotum without subparallel basal constriction.......................................................................................(genera Zeanillus Jeannel, Nesamblyops Jeannel)

2. Head with obliterated fronto-lateral carinae. Elytra lacking longitudinal grooves..................... Hygranillus Moore

- Head with long and distinct fronto-lateral carinae. Elytra with longitudinal grooves................................. 3

3. Basal constriction of pronotum with distinct tubercle, bearing basolateral pronotal seta, anterior to the posterior angles..... 4

- Basal constriction of pronotum without tubercles or denticles anterior to the posterior angles.......... Pelodiaetus Jeannel

4. With 1 elytral discal seta (Fig. 2 D, ed6). Pronotum moderately constricted basally (Wa/Wp <1.20; Wm/Wp <1.40). Beetles from South Island.................................................... Pelodiaetodes (Monosetodes) nunni, sp. n.

- With 3 elytral discal setae (Fig. 2 C, ed3, ed5–6). Pronotum strongly constricted basally (Wa/Wp> 1.20; Wm/Wp> 1.40). Bee- tles from North Island.................................................................................. 5

5. Apex of median lobe subparallel and rounded at tip (Fig. 7 D, G, J)............................................... 6

- Apex of median lobe tapering and pointed at tip (Fig. 7 A, M)................................................... 7

6. Pronotum (Fig. 6 B) more elongate (Wm/Le <1.15). Beetles larger (1.67–1.76mm). Range to the north of 34.6˚S latitude...................................................................... Pelodiaetodes (s.str.) constricticollis, sp. n.

- Pronotum (Fig. 6 C–D) more transverse (Wm/Le> 1.15). Beetles smaller (1.18–1.51mm). Range to the south of 35˚S latitude......................................................................... Pelodiaetodes (s.str.) moorei, sp. n.

7. Apex of median lobe less tapering with acute tip (Fig. 7 M). Island endemic from the east of New Zealand (Aldermen Islands)..................................................................... Pelodiaetodes (s.str.) aldermensis, sp. n.

- Apex of median lobe more tapering with acuminate tip (Fig. 7 A). Mainland species from the west coast of New Zealand ......................................................................... Pelodiaetodes (s.str.) prominens Moore