Key to species of the genus Xanthonomus

1 Pronotum with distinct obtuse hind angles. Abdomen very wide. Habitus as in Fig. 2 in Steel (1955). Body length: 2.50 mm. Malaysia ............................................................................ X. latus Steel, 1955

- Pronotum with widely rounded hind angles. Abdomen distinctly narrower........................................ 2

2 Pronotum slightly transverse, with two median, shallow and oval impressions. Elytra yellow. Habitus as in Fig. 1 in Steel (1955). Body larger: 2.50–2.80 mm. Aedeagus as in Fig. 5 in Steel (1955). Indonesia (Buru)................................................................................................... X. toxopeanus (Bernhauer, 1926)

- Pronotum distinctly transverse, without median impressions. Elytra darker. Body smaller............................ 3

3 Median lobe moderately wide; parameres distinctly not exceeding apex of median lobe (Fig. 152). Habitus asi n Fig. 142. Body larger: 1.87–2.25 mm. Indonesia (New Guinea).............................................. X. guineensis sp. n.

- Median lobe narrow; parameres reaching apex of median lobe (Fig. 159). Habitus as in Fig. 143. Body smaller: 1.61–1.80 mm. Papua New Guinea ...................................................................... X. thayerae sp. n.