Brachinus (Metabrachinus) tetragrammus Chaudoir, 1876

Akhil, S. V., Divya, M. & Sabu, K. Thomas, 2020, Bombardier beetles of genus Brachinus Weber, 1801 (Carabidae: Brachininae Brachinini) from India, Zootaxa 4816 (4), pp. 576-600 : 594

Brachinus (Metabrachinus) tetragrammus Chaudoir, 1876

Fig. 1f

Brachinus tetragrammus Chaudoir, 1876: 54 ; Andrewes, 1924a: 117; 1930a: 52.

Type locality. India: Bengal, coll. Dr. Bacon.

Type depository. MNHN .

Specimen examined (n=1). Syntype labelled “‘Ind.or.bor.’, coll. Dr. Bacon, det. Chaudoir”.

Description. Length 8.5–9.0 mm. Head, pronotum, palpi and first four segments of antennae dark reddish yellow; legs and two spots on each elytron pale reddish yellow; antennal segments 5–11 dark brown; eyes grey; scutellum brownish black; median groove of pronotum dark reddish brown, lateral margin dark brown; elytra black.

Head stout, wider than long, smooth, glabrous, matt; eyes, protruding; apical segment of palpi sub-cylindrical, truncate; antennae, short, stout, not reaching the middle of the elytra, segment 3 longest, equals the combined length of segments 1 and 2.

Pronotum narrow, longer than broad, matt, rough, punctated, pubescent; disc with apical margin straight, lateral region of apical margin slightly projecting forward, basal margin sinuate, convex; anterior two-thirds of lateral margin convex, posterior third divergent, hind angles pointed, not projecting laterally; median groove moderately deep; lateral bead narrow.

Elytra subparallel, flat, matt, punctated, pubescent; humerus rounded; apex with a well-defined re-entrant angle, having a membranous border; scutellum very small, pointed; striations moderately deep, carinate, intervals wide, both striations and intervals covered by setae; two spots on each elytron, first extended oval with transverse elongation, extending between striations 4 and 8, in the middle of elytra, second at the apex, square shaped.

Distribution. INDIA: Bengal; Bihar: Pusa; Maharashtra: Nagpur, Bandra; Odisha: Surada; Karnataka: Belgavi; Kerala: Malabar.

Figures

FIGURE 1. Dorsal habitus of Indian Brachinus species: a) B. dryas Andrewes, 1936 (holotype, BMNH); b) B. inops Andrewes, 1932 (holotype, BMNH); c) B. hexagrammus Chaudoir, 1876 (syntype, MNHN); d) B. sexmaculatus Dejean, 1825 (syntype, MNHN); e) B. tetracolon Chuadoir, 1876 (syntype, MNHN); f) B. tetragrammus Chaudoir, 1876 (syntype, MNHN); g) B. pictus (Hope, 1833) (ZSIM); h) B. cinctellus Chaudoir, 1876 (syntype, MNHN); i) B. eucosmus Andrewes, 1937 (holotype, BMNH)