Key to the groups of Siobla Cameron 1 Body distinctly metallic blue, head sometimes with reddish or greenish tinge.................................... metallica group - Body colour various, but without distinct metallic tinge.............................................................................................. 2 2 Anterior slope of mesoscutellum almost impunctate, strongly shiny; posterior slope densely punctured, interspaces distinct .................................................................................................................................................... grahami group - Anterior slope of mesoscutellum densely punctured, shiny interspaces distinct or absent, seldom wider than diameter of a puncture; posterior slope extremely densely punctured, without shiny interspaces, matt ............................... 3 3 Mesoscutellum strongly elevated, much higher than level of scutum, with acute peak, posterior slope perpendicular (Fig. 6i); apical 2/5 of fore wing distinctly infuscate; antenna black on apical 2/3, brownish on basal 1/3; lancet broadened before apex, serrulae strongly protruding (Fig.6k); valviceps of penis valve broad, apical 1/3 distinctly narrowed, dorsal margin with a few large teeth, laterally distinctly convex (Fig.6l) .................... acutiscutella group - Mesoscutellum flat or elevated, not higher than level of scutum, apex not acute, posterior slope oblique (Fig.9c); wings hyaline; if mesoscutellum higher than level of scutum or fore wing infuscate at apex, then lancet not broadened before apex and serrulae not strongly protruding; valviceps of penis valve broad, or narrow with many small marginal teeth on dorsum............................................................................................................................................. 4 4 Mesoscutellum black; valviceps of penis valve broad at least on basal 2/3 (Figs.2b, c, d) ........................................ 5 - Mesoscutellum yellowish brown; valviceps of penis valve narrow (Fig.2a) .............................................................. 8 5 Antenna black, middle or apical antennomeres white or pale brown ......................................................................... 6 - Antenna black or reddish, without white ..................................................................................................................... 7 6 1st to 5th antennomeres black, 4 apical antennomeres white; lancet narrowing towards apex, serrulae weakly protruding, not sharp ................................................................................................................................... venusta group - Some middle antennomeres partly white or pale brown, base and apex of flagellum black; lancet distinctly broadened before apex, serrulae strongly protruding, sharp (Fig. 3i) ...................................................... annulicornis group 7 Hind trochanter pale, apical margin of hind coxa and basal margin of hind femur sometimes pale.............................. ............................................................................................................................................................ formosana group - Hind trochanter entirely or mostly black ................................................................................................. sturmii group 8 Antenna black with 4–5 apical antennomeres white; lancet strongly sclerotized, apical 3 annular sutures distinct and complete (Fig. 9g) ...................................................................................................................................... sheni group - Antenna yellow brown, apical antennomeres sometimes black; lancet weakly sclerotized, apical annular sutures vestigial .............................................................................................................................................................. ferox group

Published as part of Niu, Gengyun & Wei, Meicai, 2010, Revision of the Siobla annulicornis, acutiscutella and sheni groups (Hymenoptera: Tenthredinidae), pp. 45-65 in Zootaxa 2643 on pages 47-48, DOI: 10.5281/zenodo.198643