Key to male Parathalassiinae in the Australasian Region

Ten species are currently known from the region, although additional species undoubtedly occur. Since a number of species are known only from males, female diagnostic features as they are understood, are summarized in the generic diagnoses above.

1 Wing with vein M 2 present; cell dm usually present (Fig. 52), but sometimes cell dm and crossvein dm-m absent (Shamshev & Grootaert 2005, fig. 12)................................................................................ 5

- Wing with vein M 2, cell dm and crossvein dm-m absent (Fig. 22)............................ Chimerothalassius … 2

2 Palpus elongate and gradually enlarged apically (Figs 12, 14) (New Zealand)..................................... 3

- Palpus abruptly capitate apically, narrow basally (Figs 19, 27, 28) (New Caledonia)................................ 4

3 Head and thorax primarily silver-grey pruinose; mesonotal setae rather short and weak; legs pale yellowish; palpus largely yellow (Fig. 12); genal setae weak and pale (Fig. 12); hypopygium with phallus tip funnel-shaped (Shamshev & Grootaert 2002, fig. 20)................................................................... C. ismayi Shamshev & Grootaert

- Head and thorax primarily dark brown-grey pruinose; mesonotal setae strong; legs brownish; palpus dark brown (Figs 14, 15); genal setae strong and dark (Fig. 14); hypopygium with phallus tip not expanded (Fig. 16).......... C. marshalli sp. nov.

4 Palpus brown (Fig. 19); antennal postpedicel with very short narrow tip (Fig. 20); mesonotum with acrostichal setae absent and dorsocentral setae strong; hypopygium with enlarged hypoproct (Figs 23–25)...................... C. riparius sp. nov.

- Palpus white (Figs 27, 28); antennal postpedicel with long narrow tip (Fig. 27); mesonotum with acrostichal and dorsocentral setae short and weak; hypopygium with short hypoproct (Fig. 33)............................... C. sinclairi sp. nov.

5 Face narrow, about width of anterior ocellus; arista-like stylus lengthened, at least 5X as long as postpedicel (as in Fig. 35; Shamshev & Grootaert 2005, figs 1, 2)...................................................... Eothalassius … 6

- Face broad, about width of combined antennal bases or wider (Fig. 41); arista-like stylus shorter, about 2X as long as postpedicel (Figs 40, 51)....................................................................... Microphorella … 7

6 Wing with cell dm and crossvein dm-m present (as in Fig. 36; Shamshev & Grootaert 2005, fig. 25)............................................................................................ E. gracilis Shamshev & Grootaert

- Wing with cell dm and crossvein dm-m absent (Shamshev & Grootaert 2005, fig. 12)..................................................................................................... E. platypalpus Shamshev & Grootaert

7 Body and legs with pale setation; head and thorax pale grey pollinose; palpus broadly clavate, flattened and pale (New Guinea).................................................................... M. papuana Shamshev & Grootaert

- Body and legs with black setation; head and thorax dark brownish or dark grey pollinose (Figs 39–42, 49–51); palpus narrowly ovate, dark brown (Figs 40, 41, 51) (Australia)............................................................. 8

8 Hypopygium with phallus elongate, tightly curled (Figs 53–55)................................. M. viticula sp. nov.

- Hypopygium with phallus relatively short, not tightly curled (Figs 43–45, 47, 48).................................. 9

9 Hypopygium with phallus tip bent and brush-like (Figs 47, 48)..................................... M. iota Colless

- Hypopygium with phallus tip straight and tubular (Figs 44, 45)................................. M. bungle sp. nov.