Key to the Lonchaeidae of Vanuatu

1. Lunule without setulae......... Tribe Earomyiini .. .. Lamprolonchaea .........................................2.

- Lunule with setulae........................... Tribe Lonchaeini ..........................................6.

2. Basal tarsomeres mainly pale, darkened only at apex.........................................................3.

- All tarsomeres brownish-black...........................................................................4.

3. Male terminalia: Phallus a slender curved J-shape, apical section sinuous half twisted to the left, apex bulbous (Fig. 10). Surstylar plate with two pointed posterior processes (Fig. 11)........................ Lamprolonchaea photinia McAlpine

- Male terminalia; phallus with a distinct basal bulge, apical section straight and simple, apex slightly flared (Fig 2). Surstylar plate without pointed posterior processes (Fig. 3)........................... Lamprolonchaea conchapinna McAlpine.

4. Male terminalia: Phallus with two basal bulges (Fig. 14). Surstylus rather triangular, not rectangular or rounded (Fig. 16).......................................................................... Lamprolonchaea ustulata McAlpine.

- Male terminalia: Phallus without basal bulges (Figs. 6 & 18). Surstylus rectangular or rounded (Figs. 8 & 19)............5.

5. Male terminalia: Phallus relatively short and wide, without spicules on apical half (Fig. 6). Surstylus relatively large and rectangular (Fig. 8)......................................................... Lamprolonchaea lustrata McAlpine.

- Phallus a slender, open J-shape, with an obvious group of small spicules apically. (Fig. 18) Surstylus small and rounded (Fig. 19)......................................................................... Lamprolonchaea vila sp. nov.

6. Male terminalia: inner surface of surstyli without an obvious row of prensisetae (teeth) (Fig. 27). Katepisternum usually with one seta near dorsal margin and arista bare........................................................ 7. Lonchaea .

- Male terminalia: inner surface of surstyli with an obvious row of prensisetae (Figs. 35 & 37). Katepisternum usually with two setae near dorsal margin and plumose arista......................................................... 11. Silba .

7. Legs entirely black. Arista plumose. Male; mid leg, tibia and basal tarsomere with an anteroventral fringe of setulae longer than width of tibia (Fig. 28). Large species, wing length more than 4mm. Male terminalia; epandrium 2x higher than wide (Figs 26 & 27).......................................................................... Lonchaea malekula sp. nov.

- At least some tarsomeres yellow. Arista bare. Male mid leg and basal tarsomere not setulose. Small species wing length approximately 2.5mm. Male terminalia; epandrium not 2x higher than wide.………..( L. impressifrons species-group).......8.

8. Male terminalia: cerci without basal stalk (Figs. 10, 37, 38). Disc of scutellum setulose. Surstyli relatively broad, mitten-shaped with a V-shaped notch on posterior margin..................................................................9.

- Male terminalia: cerci with narrow basal stalk (Figs. 21 &31). Disc of scutellum bare. Surstyli simple, pregonites relatively small and asymmetrical...............................................................................10.

9. Male terminalia: Pregonites, apex broad, blunt and medially directed, without a medial projection (Figs. 23–25)........................................................................................ Lonchaea iridala McAlpine.

- Male terminalia: Pregonites, apex slender and slightly curved, medially with a large, triangular inwardly directed process (Fig. 29).......................................................................... Lonchaea pentecosti sp. nov.

10. Male terminalia: Phallus an open J-shape, apex simple (Fig. 22). Pregonites both long and blade-like, without medial projections (Fig. 20)...................................................................... Lonchaea efate sp. nov.

- Main stem of phallus bent back towards base, apex flared (Fig. 32). Pregonites, shorter and broader with medial processes (Fig. 31)............................................................................... Lonchaea tanna sp. nov.

11. Calypteres greyish with a darker margin, fringe short and dark. Male terminalia; hypandrium with numerous finger-like ventral projections, phallus simple (Figs. 33–35)................................................ Silba erromango sp. nov.

- Calypteres white with a white fringe. Hypandrium without numerous ventral projections............................12.

12. Male terminalia; epandrium wider than high (Figs.36–37), phallus complex (Figs. 38–39)......... Silba hebridensis sp. nov.

- Male terminalia; epandrium higher than wide. Phallus a simple J-shape, with a very characteristic angled apex (Fig 40)..................................................................................... Silba perplexa (Walker) .