Key to the soldiers of Rhynchotermes

1 Mandibles larger than head, clearly visible from dorsal view when closed; apical region of each mandible extending well beyond the opposite mandible when closed (Fig. 6 B)........................................................ 2

- Mandibles shorter than head capsule, barely or not visible from dorsal view when closed; apical region of each mandible aligns to the proximal region of the opposite mandible when closed (Fig. 6 A)........................................... 3

2 Proximal region of frontal tube constricted; apical region bulbous (Fig. 3 C, 4C)......................... R. bulbinasus

- Frontal tube elongate, subcylindrical (Fig. 3 H, 4H)................................................ R. perarmatus

3 Mandibles with inner margin serrated, strongly curved (Fig. 5 A, F, G, I).......................................... 4

- Mandibles with inner margin smooth, evenly curved (Fig. 5 B, D, E)............................................ 7

4 In profile, dorsal margin of head and margin of frontal tube almost straight (Fig. 4 F, I).............................. 5

- In profile, dorsal margin of head and margin of frontal tube markedly concave (Fig. 4 A, B, D, E, G).................... 6

5 Length of frontal tube equal or slightly longer than length of head (see setae Fig. 4 I); head capsule without frontal tube wider than longer (Fig. 3 I)............................................................................. R. piauy

- Length of frontal tube much longer than length of head (see setae, Fig. 4 F); width and height of head capsule without frontal tube approximately equal (Fig.3 F)........................................................ R. matraga sp. nov.

6 Head with a slightly constriction behind antennae, antennae articles long (Fig. 3 A, 4A, 5A)...................................................................................................... R. amazonensis sp. nov. ( major)

- Head capsule rounded in dorsal view, antenna articles short (Fig. 3 G, 4G, 5G,)........................ R. nasutissimus

7 Length of frontal tube equal to length of head (Fig. 3 D, 4D, 5D).................................. R. diphyes ( major)

- Length of frontal tube distinctly longer than head........................................................... 8

8 Frontal tube conical, mandible thin, four bristles on head (Fig. 3 B, 4B, 5B).............. R. amazonensis sp. nov. (minor)

- Frontal tube subcylindrical, oriented downwards, six to ten bristles on head (Fig.3 E, 4E, 5E)........... R. diphyes (minor)