Siemssenius rufipennis group

Diagnosis. Length 8.3–12.7 mm, width 3.9–6.4 mm. General color of adults black, only elytra red or reddish brown, last two abdominal ventrites dark reddish brown, sometimes all abdominal ventrites reddish brown (Figs 6 A–6B). Antenna filiform, relatively longer in male (Fig. 9 A), as long as body, antennomeres III–V apically widened, length ratios of antennomeres III to XI about 1.0: 1.3: 1.3: 1.3: 1.3: 1.1: 1.3: 1.2: 1.5, and length to width ratios of antennomeres III to XI about 2.9: 3.7: 4.0: 4.4: 4.6: 4.2: 4.7: 5.1: 7.8; relatively shorter in female (Fig. 9 B), about 0.8x as long as body, antennomeres III–V apically widened, length ratios of antennomeres III to XI about 1.0: 1.3: 1.3: 1.3: 1.3: 1.3: 1.2: 1.1: 1.4, and length to width ratios of antennomeres III to XI about 3.2: 4.1: 3.9: 4.5: 4.5: 4.8: 4.8: 4.6: 6.5. Apical margin of abdominal ventrite V with two well developed incisions in male, surface with deep, wide, longitudinal groove, apically expanding into most of area between incisions; relative longer than in the S. metallipennis group; apical margin of ventrite IV with very small incision midway (Fig. 9 E). Ventrite V not modified in female, apical margin rounded, disc without depression; apical margin of ventrite IV straight. Dense setae along apical margins of triangulate processes on abdominal ventrite VIII in female (Figs 7 D, 8E, 10D, 11D).