(Excluding Genus No. 2 sp. 1, sensu Müller-Liebenau, 1984. *Based on the original description)
1. Tarsal claws dentate (Figs 41, 53, 64); posterior marginal spines of tergite IX with broadly interrupted medially (Figs 44, 54)................................................................................ 2 (subgen. Chopralla )
- Tarsal claws edentate (Figs 2, 26); posterior marginal spines of tergite IX contiguous and complete (Fig. 13)........................................................................................... 9 (subgen. Centroptella )
2 (1). Prostheca of right mandible neither bifid nor plumose, situated close to incisors (Figs 35–36, 60)...................... 3
- Prostheca of right mandible forked and plumose, situated relatively far from incisors (Fig. 51)...................... 4
3 (2). Pronotum with a pair of submarginal median tubercles posteriorly (Figs 62–63); labrum surface with simple submarginal setae [China, Vietnam]................................................................. B. (Ch.) liebenauae
- Pronotum smooth without any tubercles; labrum surface with forked submarginal setae (Fig. 37)[China]................................................................................................ B. (Ch.) bifida sp. nov.
4 (2'). Hindwing pads completely absent (cf. Müller-Liebenau 1983:fig. 2b)............................................ 5
- Hindwing pads minute but visible...................................................................... 6
5 (4). Abdominal tergite I uniformly yellow-white (cf. Müller-Liebenau 1983:fig. 6); tergites IX–X with spines on posterior margin (Marle et al. 2016: table 1) [Sri Lanka]...................................................... B. (Ch.) similis *
- Abdominal tergite I yellow-white tinged with irregular brown markings (cf. Marle et al. 2016: fig. 19); tergites VIII–X with spines on posterior margin (Marle et al. 2016: table 1) [Indonesia]............................... B. (Ch.) bintang *
6 (4'). Posterior marginal spines present only on tergites IX–X..................................................... 7
- Posterior marginal spines present on tergites IV–X......................................................... 8
7 (6). Segment II of labial palpus dorsally with a row of 4 long, simple setae on distomedial area, dorsal margin of femora with 11– 15 long, clavate setae (Marle et al. 2016: table 1) [Sri Lanka]................................ B. (Ch.) ceylonensis *
- Segment II of labial palpus dorsally with a row of 3 long, simple setae on distomedial area, dorsal margin of femora with 8– 10 long, clavate setae (Marle et al. 2016: table 1) [Malaysia].................................... B. (Ch.) pusilla *
8 (6'). Prostheca of right mandible bifurcated and plumose; tergites V–X with acute triangular spines on posterior margins; gill I less than 4 times as long as wide [China]..................................................... B. (Ch.) fusina
- Prostheca of right mandible plumose but not forked; tergites IV–X with acute triangular spines on posterior margins (Marle et al. 2016: table 1); gill I more than 5 times as long as wide [Vietnam]............................ B. (Ch.) colorata *
9 (1'). Hindwing pads completely absent..................................................................... 10
- Hindwing pads minute but visible..................................................................... 11
10 (9). Outer incisors of mandibles with a small lateral denticle, segment III of labial palpus rounded with distal margin slightly expanded (Müller-Liebenau 1983) [Sri Lanka]................................................ B. (C.) soldani *
- Outer incisors of mandibles without lateral denticle, segment III of labial palpus subrectangular with distal margin straight and unexpanded (Marle et al. 2016) [Indonesia]........................................... B. (C.) papilionodes *
11 (9'). Length of maxillary palpus approximately 1/2 of galealacinia [China]............................ B. (C.) longisetosa
- Maxillary palpus subequal to galealacinia in length....................................................... 12
12 (11'). Body with relatively uniformly brown colouration (Fig. 31); antennal pedicel about 2 x length of scape (Fig. 16); terminal segment of labial palpus rectangular (Fig. 18); posterior marginal spines present on tergites II–X [China]............................................................................................. B. (C.) quadrata sp. nov.
- Body with relatively contrasting colour pattern (Figs 14–15); anternnal pedicel slightly longer than scape; terminal segment of labial palpus irregular trapezoidal, distal margin truncated (Fig. 8); posterior marginal spines present on tergites IV–X [China]........................................................................... B. (C.) ovata sp. nov.