Brachytrycherus femoralis (Arrow, 1928)

Chang, Ling-Xiao, Bi, Wen-Xuan & Ren, Guo-Dong, 2019, A review of the genus Brachytrycherus Arrow (Coleoptera, Endomychidae) of mainland China with descriptions of three new species, ZooKeys 880, pp. 85-112 : 85

Brachytrycherus femoralis (Arrow, 1928) Figs 17 , 18 , 19

Engonius femoralis Arrow, 1928: 347.

Diagnosis.

Brachytrycherus femoralis can be separated from all its congeners by having three elytral maculae; sides of elytra strongly converging from its 1/2 length towards apex, lateral margins moderately widely flattened, not vanishing at apex.

Material examined.

China: Guangxi Province: Jinxiu, Yinshan Protection Station, 27.VI.2016, Yu-Yang Lei leg. (1 male, 2 females, CCLX); Huanjiang Yangmeiao Protection Station, 15.VIII.2016, Ling-Xiao Chang leg. (2 males, CCLX); Jinxiu, Dayaoshan, 22-24.IV.2018, Chun-Fu Feng leg. (2 females, CCLX); Jinxiu, Yinshan Protection Station, 1500 m, 12.VIII.2015, Ling-Xiao Chang leg. (2 males, 3 females, MHBU); Jinxiu, Dayaoshan, 17.V.2014, Zhi-Lin Chen leg. (1 female, MHBU); Longsheng, Huaping, 15.X.2005, Ji-Liang Wang & Chao Gao leg. (1 female, MHBU).

Description.

Length 9.4-11.2 mm, width 4.3-5.4 mm. Body oval, about 2.1-2.3 times as long as wide; moderately convex; shiny. Colour black with purple sheen, three orange-red maculae on each elytron.

Head. Antenna long and rather slender, nearly 1/2 body length, with antennomeres 1-8 distinctly longer than wide; scape approximately 4.0 times as long as pedicel; antennomere 3 as long as 4 and 5 combined; antennomeres 4 nearly as long as 5, antennomeres 5-8 gradually shorter; club composed of three antennomeres, moderately broad, flat, loose. Maxilla with terminal palpomere longer than wide, slightly longer than palpomere 3, tapering anteriorly, truncate apically.

Thorax. Pronotum 2.1-2.2 mm long, 3.5-4.2 mm wide; widest near 1/2 of pronotal length; finely and densely punctate; lateral margins rather narrowly bordered, sides undulate; front angles produced anteriorly, rather acute; disc weakly convex, two small round raised area laterally; transverse wrinkle and inflexed laterally; median furrow shallow, extending to 1/2 length of pronotum; lateral sulci linear, deep, extending to basal 1/3 length of pronotum; basal sulcus weakly undulate, deep. Prosternal process moderately separates procoxae; not extending beyond coxae; sides nearly parallel, expanded apically; posterior margin in male truncate and emarginate in female. Mesoventral process transverse, lateral margins weakly widening apically and overlapping part of mesocoxae; posterior margin nearly straight.

Elytra 6.3-7.3 mm long, 3.0-3.3 times as long as pronotum and 1.2-1.3 times as wide as pronotum, sides curved, widest near 1/2 length of elytron; finely and densely punctate; humeri prominent. Each elytron with three irregular orange-red maculae. Anterior two elytral maculae located near basal 1/4, lateral maculae oval, almost confined to umbo; medial macula nearly round, larger than lateral one, sometimes narrowly connected. Posterior macula located near apical 1/4, weakly transverse, nearly cloud-form, outer sides far from elytral lateral margin, inner margin of macula far from elytral suture. Protibia in male with rather long sharp tooth near 1/2 length on inner edge, in female without tooth; mesotibia in male with small sharp tooth behind 1/2 length on inner edge, and then abruptly curved to apex, in female without tooth.

Ventrite V with lateral margins gently converging posteriorly; posterior margin truncate in male and weakly curved in male medially.

Aedeagus ( Fig. 5 ) rather long, heavily sclerotized, straight. Median lobe one branched apically; branch long and strongly reflexed upwardly, acute apically. Tegmen basal, comparatively large, ring-shaped.

Distribution.

China (Guangxi), Laos, Vietnam (Tonkin). First records from China.

Type locality.

Lectotype: Laos, 1 male; Syntype: Vietnam (Tonkin), 1 male.

Biology and ecology.

The adults were found active and feeding on the mould growing on dead bamboos at night ( Fig. 18 ). The adults and larvae were brought back and placed in artificial conditions to rear. The last instar larvae pupated on surface of dead bamboos, from their pupal stage to matured to adults in approximately seven to nine days ( Fig. 19 ).

Figures

Figure 5. Habitus of B. denticulatus sp. nov. (male). A dorsal view B ventral view C lateral view. Scale bars: 2 mm.

Figure 17. Habitus of B. femoralis A male B female; 1 dorsal view 2 ventral view. Scale bar: 1 mm.

Figure 18. Habitats of B. femoralis. A large pile of dead bamboos in Guangxi, China B adult of B. femoralis sp. nov. feeding on the mold growing on dead bamboos.

Figure 19. Living adults, larva, and pupae of B. femoralis in artificial conditions. A last instar larvae B pupae C, D newly emerged adult.