Key to the species of Liostenogaster occurring in the Philippine Islands 1. Claws of all legs simple, without tooth on inner side. Apical margins of female clypeus crenate. Male antenna elongate, all flagellomeres longer than wide. T2 with large lateral rounded spots............................... L. bimaculata Selis -. Claws with tooth on inner side. Apical margins of female clypeus not crenate. Male antenna shorter, some flagellomeres as wide as long or wider.................................................................................. 2 2. Mesoscutum with four yellow lines, two submedian and two lateral. Mandibles bidentate, inner tooth absent or at most visible as shallow elevation of margin, median tooth with convex proximal margin. Propodeum yellow except basal triangular dark brown marking. Dorsal outline of T 1 in lateral view practically straight, except for basal and apical convexity; apical convexity strongly marked...................................................................... L. varipicta (Rohwer) -. Mesoscutum without four yellow lines. Mandibles tridentate, inner tooth in male short but distinctly pointed, median tooth apically truncate. Propodeum less extensively yellow............................................................ 3 3. Frons nearly impunctate. Propodeum with yellow on apical half and on sides of basal half. Apical expansion of T1 weakly convex in lateral view, smoothly passing on base of T2. F10 of female antenna 1.8× as long as basally wide. Male clypeus with basolateral margins parallel-sided.......................................................... L. maculiceps Selis -. Frons densely punctate. Propodeum with yellow restricted to apical half or less. Apical expansion of T1 strongly convex, distinctly sloping down before base of T2. F10 of female distinctly shorter. Male clypeus with basolateral margins converging above......................................................................... L. nitidipennis (de Saussure)

Published as part of Selis, Marco, 2018, Notes on the subfamily Stenogastrinae (Hymenoptera: Vespidae) in the Philippine Islands, with description of nine new species, pp. 383-410 in Zootaxa 4514 (3) on page 391, DOI: 10.11646/zootaxa.4514.3.5, http://zenodo.org/record/2608087