Key to species of Thaumastocoris

1 Forecoxae inserted at a distance less than coxal width (Figure 15 B); pronotum weakly constricted medially (Figure 15 D); pronotal disc broader than callosite region (Fig 15 D)........................................................... 2

- Forecoxae inserted at distance equal to or more than coxal width (Figure 10 B; 11B; 12B; 13B; 17B); pronotum weakly to

strongly constricted medially (Figure 10 D; 11A; 12D; 13A; 14D; 16E; 17D); pronotal disc equal to or broader than callosite region (Figure 10 D; 11A; 12D; 13A;14D;16E;17D)......................................................... 3 2 Labium short, reaching anterior margin of prosternum (Figure 15 B); eyes weakly pedicellate (Figure 7 C,D; 15A,D); forecoxae subcontiguous (Figure 15 B); prosternum bipartite (Figure 15 B)............................................ T. petilus

- Labium long, reaching submarginal posterior prosternum; eyes strongly pedicellate (Figure 4 C,D; 8A,B); forecoxae separated by more than half coxal width; prosternum undivided........................................................ 4

3 Pronotum with distinctive tubercle on anterolateral margin of callosite region (Figure 8 C,D; 9A,B; 16E; 17D)............ 5

- Pronotum tuberculate (Figure 10 D; 13A; 14D) to rounded (Figure 11 A; 12D) but never with distinctive tubercle on anterolateral margin of callosite region............................................................................ 6

4 Small species, males 2.37–2.41 mm, females 2.57–2.69 mm; antennae mostly light brown; AII with subapical dark annulations; subapical third AIII and apical two-thirds AIV dark brown to fuscous (Figure 8 A,B); abdominal venter dark brown; paramere with broad medial keel (Figure 19 D).......................................................... T. roy

- Large species, males 2.96–3.24 mm, females 3.24–3.36 mm; antennae mostly straw-coloured; apical half of AIII and all but sub basal ring of AIV dark brown to fuscous (Figure 4 C,D); abdominal venter yellowish brown; paramere with apical hornlike projection (Figure 18 E,F)........................................................................ T. hackeri

5 Small species, males 2.41–2.65 mm, females 2.41–2.69 mm; abdomen narrow, lateral margins subparallel, barely visible from above (Figure 8 C,D); pygophoral lock short, invaginated basally, strongly concave apically (Figure 16 G; 19E).... T. safordi

- Large species, males 3.08–3.20 mm, females 2.96–3.16 mm; abdomen expanded laterally, distinctly evident from above (Figure 9A,B); pygophoral lock elongated, weakly concave apically (Figure 17 G; 19F)........................... T. slateri

6 Distinctive tubercle posteroventrally on propleuron (Figure 10 B,E); abdominal venter strongly expanded (Figure 3 C,D); pronotum strongly constricted medially (Figure 3 C,D; 10D)................................................ T. busso

- Posteroventral angle of propleura without tubercle (Figure 11 B; 12B; 13B); abdominal venter either expanded or narrow; pronotum weakly to strongly constricted medially (Figure 11 A; 13A).............................................. 7

7 Mandibular plates strongly recurved laterally (Figure 6 A,B; 7A,B; 13A; 14A); bucculae strongly explanate, margins thickened, reniform posteriorly (Figure 13 B; 14B).............................................................. 8

- Mandibular plates weakly to strongly recurved (Figure 11 A; 12A); bucculae margin thin to weakly explanate, not thickened or reniform posteriorly (Figure 11 B; 12B)................................................................... 9

8 Apex of pygophoral lock acute (Figure 19 A); AIII yellowish brown (Figure 6 A,B); female pronotal disc fuscous (Figure 6 B), sexually dimorphic............................................................................. T. nadeli

- Apex of pygophoral blunt (Figure 19 B); AIII subapically light brown; (Figure 7 A,B); female pronotal disc cream-coloured (Figure 7 B), male concolorous (Figure 6 A)....................................................... T. peregrinus

9 Labium elongate, reaching just beyond midpoint of forecoxae; medial margin of corium convex; apex of corium at membrane blunt, medial margin more than 45° to costal margin (Figure 5 A; 5B)........................................... 10

- Labium short to moderately long, not reaching beyond midpoint of forecoxae (Figure 11 B; 12B); medial margin of corium straight to excavate (Figure 11 F); apex of corium at membrane weakly to strongly narrowed, never blunt medial margin less than 45° to costal margin (Figure 3 A,B; 5C,D; 6C,D)....................................................... 11

10 Body elongate, costal margins subparallel; dorsum yellowish brown; hemelytra extending to T8; eyes strongly pedicellate; abdomen strongly expanded laterally, visible beyond costal margins from above (Figure 5 B).................. T. kalaako

- Body ovoid; dorsum dark brown; hemelytra covering abdomen; eyes moderately pedicellate; abdomen not expanded laterally, barely visible beyond costal margins from above (Figure 5 A)......................................... T. macqueeni

11 Labium very short, not reaching beyond anterior margin of prosternum; prosternum distinctly swollen, truncate anteriomedially....................................................................................... T. australicus

- Labium reaching beyond anterior margin of prosternum (Figure 11 B; 12B); prosternum flat to weakly swollen, not distinctly swollen............................................................................................ 12

12 Prosternum weakly swollen anteriorly (Figure 12 B); pygophoral lock elongate, weakly concave medially, with a subapical notch; paramere securiform, elongate, weakly spatulate distally (Figure 18 D)................................ T. majeri

- Prosternum weakly excavate anteriorly (Figure 11 B); pygophoral lock weakly trapezoidal (Figure 18 C,G,H), apices variously expanded or pointed, without notches (Figure 18 D); paramere subrectangular or elongate, recurved or distinctly spatulate apically (Figure 18 C,G,H)................................................................................ 13

13 Dorsum yellowish brown with contrasting dark brown to fuscous markings (Figure 6 C,D); labium not reaching anterior margin of forecoxae; pygophoral lock trapezoidal, apices flared and rounded; paramere elongate, spatulate apically (Figure 18 G,H)............................................................................................ T. ohallorani

- Dorsum light golden to yellowish brown with contrasting cream to light brown markings (Figure 4 A,B); labium reaching anterior margin of forecoxae (Figure 11 B); pygophoral lock moderately elongate, weakly trapezoidal, apices strongly flared, medial angles weakly pointed; paramere subrectangular, basal angle recurved (Figure 18 C)............... T. freomooreae