Key to the genera of the tribe Ptinini from Madagascar, Mascarenes and adjacent regions

1 Pronotum with one distinct central bump; species rather slender, ratio of length to width of elytra 1.4–1.6; without sexual dimorphism.......................................................................................... 2

- Pronotum with two lateral bumps; species more robust, wide, ratio of length to width of elytra 1.5–2.0; with sexual dimorphismfemales slightly wider.................................................................................. 3

2 Pronotum with more or less distinct lateral depressions on the sides of central bump................................................................................................................ Xylodes Waterhouse, 1876

- Pronotum with only distinct central bump, without lateral depression........................ Trymolophus Bellés, 1990

3 Two lateral bumps distinct; species without sexual dimorphism, ratio of length to width of elytra 1.5–2.0................................................................................................. Sulcoptinus Bellés, 1988

- Two lateral bumps indistinct, but visible; species with feeble sexual dimorphism (shape of body—ratio of length to width of elytra 1.5–2.0 in male, ratio of length to width of elytra 1.5–1.7 in female)....... Ptinus (Gynopterus) Mulsant & Rey, 1868