Key to the Philippine species of Brachinus (modified from Tian & Deuve, 2007)

1 Bicolor, head and pronotum yellow, elytra dark brown, body smaller (5.5 mm in length)............ B. luzonicus Chaudoir

- Unicolor, head, pronotum and elytra dark brown, body larger (more than 10.0 mm in length).......................... 2

2 Head with yellow or red spots between eyes, mentum with deep basal pits or furrows, legs with femora dark brown at apex...................................................................................................... 3

- Head without spot between eyes, mentum without basal pits or furrows, legs with entire femora yellowish..................................................................................................... B. piceus Chaudoir

3 Light brown, spots between eyes large and yellow, frontal impressions convergent backwards, mentum with two basal furrows, but without fovea, elytral costae obscure........................................... B. philippinensis Tian & Deuve

- Dark brown, spots between eyes small and dark brown, frontal impressions paralleled backwards, mentum with two basal well-defined foveae, elytral costae more or less distinct....................................................... 4

4 Labial palpiger unisetose............................................................... B. palawanensis n. sp.

- Labial palpiger bisetose................................................................................ 5

5 Apical palps of mouthparts dilated, antennae longer, extending over middle of elytra......... B. solidipalpis Tian & Deuve

- Apical palps of mouthparts normal, antennae shorter, extending at about middle of elytra........................... 6

6 Elytra broad, with shoulders square......................................................... B. grootaerti n. sp.

- Elytra slender, with shoulders broad.................................................... B. mindanaoensis n. sp.