Key to species of Bicaubittacus Tan & Hua, gen. nov. (male)

1. Gonocoxites prolonged caudally, then divided into two long columnar prolongations (Figs 1 B, 2A, 3A); apex of proctiger emarginated into two unequal processes, roughly L-shaped, dorsal (subapical) one rounded and broad, ventral (apical) one slender, tapering apically .............................................................................................................. 2

- Gonocoxites not prolonged caudally, with a large flat prolongation on each side (Figs 7 A, C); apex of proctiger

rounded without process; China ................................................ Bi. longiprocessus (Huang & Hua, 2005), comb. nov. 2. Posterior margins of terga VI–VIII deeply emarginate, V-shaped (Fig. 4 D)); posterior angles of terga VI–VII blackish brown....................................................................................................................................................................... 3

- Posterior margin of tergum VII straight; posterior angles of terga VI–VII yellowish brown ...................................... 4

3. Dorsal margin of epandrial appendage extending ventro-mesad into a large subtriangular lobe (Figs 2 A, B); gonostylus short, with an upturned, truncate, flat and broad apex (Fig. 2 C); China ................................................................... ............................................................................................... Bi. appendiculatus (Esben-Petersen, 1927), comb. nov.

- Dorsal margin of epandrial appendage extending caudo-mesad into a long sabre-shaped lobe with a row of black spines (Figs 4 A, D); gonostylus long and slender (Fig. 4 C); China .................................................. Bi. yangi, sp. nov.

4. Epandrial appendage forked apically into a pair of slender prongs, similar size in lateral view; distal prolongations of gonocoxites without thick setae; cerci pointed apically; gonostylus short and slender, oblique straight in lateral view; Myanmar ....................................................................................................... Bi. burmanus (Tjeder, 1974), comb. nov.

- Epandrial appendage strongly cleft apically into a short upper prong and a large lower elongation, distinctly longer and broader than the upper prong from lateral view (Figs 5 B, 6A); distal prolongations of gonocoxites with a row of long thick black setae (Figs 6 A, G); cerci flat and broad, apex rounded (Fig. 6 A); gonostylus long, L-shaped in lateral view (Fig. 6 F); China .................................................................................................... Bi. mengyangicus, sp. nov.