Key to the workers of Labiotermes

Workers of Labiotermes can be readily identified by the presence of a row of short spines on lateral margins of meso­ and metanotum (Fig. 4 C) and the enlarged abdomen. Identification to species level usually requires examination of the enteric valve armature (Fig. 16).

1. Front coxae rounded, without any projection near base (Figs. 3 J, 4D, 8J) ................. 2

­ Front coxae with a rounded or conical projection near base (Figs. 1 G, 7F) ................ 4

2. Enteric valve with 3 large and one small ridge covered with short spines (Fig. 16 D) ... ....................................................................................................................... L. labralis

­ Enteric valve with 3 or 6 ridges partially covered with dense, long hairs (Figs 16 C, 16H) ............................................................................................................................. 3

3. Head with very few hairs (Fig. 3 G); enteric valve with 6 distinct ridges (Fig. 16 C) ..... ..................................................................................................... L. guasu, new species

­ Head with numerous hairs (Fig. 8 G); enteric valve with 3 distinct ridges of unequal and 3 vestigial ridges (Fig. 16 H) .......................................... L. oreadicus, new species

4. Projection on front coxae conical, with a sharp point (Fig. 1 G) ................................. 5

­ Projection on front coxae without a sharp point (Fig. 2 O, 6F) ................................... 6

5. Enteric valve with a single ridge covered with very short spines (Fig. 16 A); width of head 0.95–1.2mm .................................................................................... L. brevilabius

­ Enteric valve with 6 distinct ridges of irregular shape, covered with long, fine and straight spines (Fig. 16 I); width of head 1.25–1.7mm ....................... L. orthocephalus

6. Head and body densely covered with fine, long hairs (Fig. 10); enteric valve with 6 ridges covered with long and curved spines (Fig. 16 J) ............................... L. pelliceus

­ Head with numerous short hairs (Figs. 2 L, 5M); enteric valve with 4–6 ridges covered with straight spines (Fig. 16 B, E–G) ........................................................................... 7

7. Mandibles with very large apical teeth; left mandible index ca. 1.4; enteric valve with 5 elongate ridges (Fig. 16 F) ...................................................................... L. leptothrix

­ Left mandible index less than 1.1; enteric valve with 4–6 ridges ............................... 8

8. Front and middle trocanters with small spines; enteric valve with 6 finger­like ridges (Fig. 16 G) ................................................................................................ L. longilabius

­ Front and middle trocanters without small spines; enteric valve with 4–6 ridges (usually 4) .......................................................................................................................... 9

9. Posterior margin of mesonotum with only a few lateral hairs (Fig. 2 M); head and postclypeus with sparse hairs (Fig. 2 L); length of hind tibia 1.2–1.5mm ........ L. emersoni

­ Posterior margin of mesonotum with a line of 8 or more hairs (Fig. 5 N); head and postclypeus with dense hairs (Fig. 5 M); length of hind tibia 1.5–1.7mm ... L. laticephalus