Key to Japanese species of Salka
1. Mesonotum pale, concolorous with vertex................................................................ 2
– Mesonotum dark, not concolorous with vertex............................................................. 4
2. Anteclypeus pale, concolorous with rest of face............................................................ 3
– Anteclypeus infuscated............................................................... S. denticulata sp.nov.
3. Black spot of vertex notched anteriad, nearly reaching laterofrontal suture..................... S. circumflexa sp. nov.
– Black spot slightly emarginate anteriad, not reaching laterofrontal suture....................... S. okinawana sp. nov.
4. Anteclypeus pale, concolorous with rest of face............................................................ 5
– Anteclypeus infuscated, not concolorous with rest of face.................................................... 7
5. Vertex with black spot only (rarely pair of black fasciae anteriorly), lorum pale................................... 6
– Vertex with black spot and pair of black fasciae anteriorly, lorum brownish..................... S. trimaculata sp. nov.
6. Black spot of vertex reaching posterior margin of vertex..................................... S. dimorpha sp. nov.
– Black spot of vertex not reaching posterior margin of vertex.................................... S. diversa sp. nov.
7. Black spot of vertex large, notched anteriad, nearly reaching laterofrontal suture............... S. maesatoensis sp. nov.
– Black spot small, slightly emarginate anteriad or not, not nearly reaching laterofrontal suture...... S. nusukuensis sp. nov.