Key to male Thinolestris

1. Thorax black in ground­colour. Antenna with third segment dark brown .................. 2

­ Thorax yellowish in ground­colour. Antenna yellow (third segment a little darker than basal segments) ............................................................................................................ 3

2. Basal abdominal tergite with a narrow yellow anterior margin. Tip of hypandrium only shallowly indented (Fig. 15). Sulawesi ........... T. obscura Grootaert & Meuffels, 1989

­ Basal abdominal tergite completely black. Tip of hypandrium deeply indented (Fig. 13) Singapore, Malaysia, Brunei .......................................................... T. nigra sp. nov.

3. Hairs on abdominal tergites brownish, marginal hairs black. Setae on thorax black. Tip of hypandrium indented (Fig. 12) Papua New Guinea .................................................... ............................................................................ T. luteola Grootaert & Meuffels, 1989

­ Hairs on abdominal tergites yellowish white. Setae on thorax brown. Tip of hypandrium not indented (Fig. 14). Thailand, Malaysia T. thaica Grootaert & Meuffels, 2001