(Figs. 18–22)

Type material. Holotype (male): CHINA: “ CHINA SW Sichuan 60 km NE Yanyuan 2500 m nr. Pingchuan 25.–27. Jun 1998 " (YSC). Paratype: CHINA: Sichuan: same data as holotype, 1 ♀ (ASC).

Description. Black, dull; maxillary and labial palpi dark brunneous to brunneopiceous, antennae piceous­black with first segment vaguely paler, legs brownish­red. Head of rounded quadrangular shape, with entirely rounded, obsolete posterior angles, wider than long (ratio 1.31), eyes small, rather flat, tempora considerably longer than eyes from above (ratio 1.61), dorsal surface of head very densely, moderately finely punctate and pubescent, punctation gradually becoming sparser anteromediad; very narrow, impunctate midline present on posterior half of head; interspaces between punctures without appreciable microsculpture. Antenna short, segment 3 longer than segment 2 (ratio 1.20), segments 4–7 longer than wide, becoming gradually shorter, segment 8 about as long as wide, segments 9 and 10 slightly wider than long, last segment shorter than two preceding segments combined. Pronotum about as long as wide, slightly narrowed anteriad, narrow marginal groove disappearing downwards just in front of middle of pronotal length; disc of pronotum with complete, narrow, impunctate midline; punctation and pubescence similar to that on head but slightly finer and even denser, interspaces between punctures without microsculpture. Scutellum finely and densely punctate and setose, more densely so on apical portion, surface with extremely fine, rudimentary transverse microsculpture. Elytra short, not appreciably widened posteriad, at suture considerably (ratio 0.65) at sides distinctly (ratio 0.83) shorter than pronotum at midline; punctation fine and quite dense, finely asperate, interspaces between punctures with fine, dense, granulose microsculpture, elytra therefore appearing dull; pubescence black, dense. Wings each reduced to minute, nonfunctional stump. Abdomen with tergite 7 (fifth visible tergite) lacking pale apical seam of palisade setae; tergite 2 (in front of first visible tergite) entirely, finely and densely punctate; posterior basal line on first three visible abdominal tergites simple, almost straight; all tergites very finely and densely punctate, punctation markedly finer than that on elytra, gradually becoming vaguely sparser toward apex of each tergite and in general toward apex of abdomen; interspaces with extremely fine microsculpture of short transverse striae that become rudimentary toward middle of each tergite; pubescence black, dense.

Male. Sternite 8 with moderately wide, rather shallow, obtusely triangular medioapical emargination. Male genital segment with sternite 9 with moderately wide and deep, arcuate apical emargination (Fig. 18). Tergite 10 moderately large, triangular with differentiated apical portion with obtuse apex bearing long apical and subapical setae, otherwise moderately densely setose (Fig. 19). Aedoeagus small and wide, as in Figs. 20–22; median lobe short with parallel­sided middle portion, with short, subacute apex; paramere situated on median lobe markedly asymmetrically, with obliquely truncate apex distinctly not reaching apex of median lobe; underside of paramere with a few inconspicuous, not pigmented sensory peg setae, with five long apical setae along left lateral margin and with two minute, stout setae situated in middle of apical portion of paramere below apex (Fig. 21).

Length 16.0–17.0 mm.

Geographical distribution. Sphaerobulbus bicolor is at present known only from the type locality in southern Sichuan.

Bionomics. Nothing is known about the habitat requirements of this species.

Recognition. Sphaerobulbus bicolor resembles in external characters small specimens of S. yulongmontis (apparently endemic to Yulongshan), but it differs, in addition to the entirely different shape of the aedoeagus, by the shorter antenna, the more rounded head, by the pronotum which is appreciably narrowed anteriad, and by the absence of the microsculpture on interspaces between punctures both on the head and pronotum.

Etymology. The specific epithet is a combination of Latin bis (twice) and the noun color, ­ is, m. (color). It refers to the color of the body (black) and that of the legs (red).