Eupines (Byraxis) bisulcifrons (Broun, 1914)

Fig. 5; map Fig. 49

Byraxis bisulcifrons Broun, 1914b: 170. Hudson 1923: 364, 1934: 185.

Eupines (Byraxis) bisulcifrons: combination and subgeneric assignment by Nomura and Leschen 2006: 254. Maddison 2010: 417; Shen and Leschen 2019: 259.

Type locality: [MC] Mount Hutt.

Type depository: BMNH LT ♂, 1 PLT.

Diagnosis: Head lacking vertexal foveae; antennae 10-segmented with 2-segmented antennal club; A4, A6, A7, A8 and A10 unmodified, A5 asymmetrical and triangular, excavated at base, A9 asymmetrical, about 3 × longer than A8, inner apical margin expanded, A10 conical, slightly impressed at base, about 1.8 × longer than A9. Abdominal ventrite 2 with pair of small discal protuberances, inserted with strongly curved small apical setae; ventrite 6 unknown. Protrochanters with minute ventral spine, about one-ninth of protrochanteral width; protibiae and mesotibiae unmodified.

Redescription: Body length 1.43 mm; body colour reddish brown with lighter coloured tibiae and tarsi. Head wider than long; frons slightly narrowed at end, about half width of head at eye level; eyes slightly prominent in dorsal view, with about 22 facets; lacking vertexal foveae; antennal tubercles barely visible; lacking postantennal notches; postantennal cavities large, slightly longer than antennal tubercles in dorsal view; antennae 10-segmented with 2-segmented antennal club; A4, A6, A7, A8 and A10 unmodified, A5 asymmetrical and triangular, excavated at base, A9 asymmetrical, about 3 × longer than A8, inner apical margin expanded, A10 conical and slightly impressed at base, about 1.8 × longer than A9. Pronotum about as long as wide, wider than head at eye level; lacking lateral antebasal foveae. Elytra slightly wider than long, widest at apical two-thirds; humeral calli barely visible; sutural stria distinctively extending from base to apex. Abdomen with tergite 1 about 2.3 × longer than tergite 2; ventrite 2 with pair of small discal protuberances, inserted with strongly curved small apical setae; ventrite 6 unknown. Legs with protrochanters modified with minute ventral spine, about one-ninth of protrochanteral width; protibiae and mesotibiae unmodified. Aedeagus unknown.

Comments: Only two type specimens are known. We did not attempt to dissect the syntypes since males of this species have distinctive antennal modifications (Fig. 5B) that separate the species from congeners.

Distribution: South Island. MC.