Key to the species of Furcilarnaca (not including F. pulex as male subgenital plate badly damaged)

1 Posterior margin of male ninth abdominal tergite without any processes..................................... F. fallax

- Posterior margin of male ninth abdominal tergite with processes................................................ 2

2 Male ninth abdominal tergite with 2 pairs of processes, centre of posterior margin with 1 long, flat spine, lateral margin of apical area with 1 stout conical processes separately........................................................ F. armata

- Male ninth abdominal tergite posteriorly with 1 pair of processes in the middle.................................... 3

3 Processes of male ninth abdominal tergite digitate, widely spaced..................................... F. beybienkoi

- Processes of male ninth abdominal tergite spine-shaped, narrowly spaced......................................... 4

4 Spines of male ninth abdominal tergite with 4 denticles separately; subgenital plate longer than wide, its posterior margin shallowly splited, the lateral lobes spine-shaped, between the lateral lobes narrow and without membranous......... F. forceps

- Spines of male ninth abdominal tergite without denticles; subgenital plate broadly concave........................... 5

5 Lateral lobes of male subgenital plate obviously curved outward.......................................... F. affinis

- Lateral lobes of male subgenital plate obviously curved inward................................................. 6

6 Lateral lobes of male subgenital plate obviously curly, its apex obtuse................................... F. fractiflexa

- Lateral lobes of male subgenital plate obviously sclerotized, its apx acute......................................... 7

7 Processes of tenth abdominal tergite pointing inward; lateral lobes of subgenital plate as long as styli........ F. wufengensis

- Processes of tenth abdominal tergite pointing ventrad......................................................... 8

8 The base of lateral lobes of subgenital plate wider than its apex, membranous area reaching 1/3 of lateral lobes length; styli as long as lateral lobes........................................................................... F. chirurga

- The base of lateral lobes of subgenital plate as wide as its apical part, membranous area reaching mid of lateral lobes; styli shorter than lateral lobes.......................................................................... F. huangi