Genus Rivudiva Lugo-Ortiz & McCafferty, 1998

Key to the species in the nymphal stage (adapted from Salles & Nascimento 2009)

1. Abdominal sterna with simple setae; hind wing pads present ........................ 2 (minantenna group)

– Abdominal sterna with robust, apically pointed setae (Fig. 3B); hind wing pads absent ................. 3

2. Setae on dorsum of fore femur long (as long as maximum width of femur) and apically pointed (Salles & Nascimento 2009: fig. 32) ....................... R. minantenna Lugo-Ortiz & McCafferty, 1998

– Setae on dorsum of fore femur short (at most ⅓ maximum width of femur) and apically blunt (Salles & Nascimento 2009: figs 7, 30–31) ................................. R. inma Salles & Nieto in Salles et al., 2020

3. Scape and pedicel without apically pointed setae; fore tarsus with long setae (Salles & Nascimento 2009: fig. 17) .................................................................... R. oonirikoperi Cruz in Salles et al., 2020

– Scape and pedicel with apically pointed setae (Fig. 1A); fore tarsus without long setae ................... ........................................................................................................................... 4 (trichobasis group)

4. Labrum with medial emargination (Figs 1B, 12A), hypopharynx with distomedial projection (Figs 1F, 12F) ................................................................................................................................................... 5

– Labrum without medial emargination (Figs 4A, 8A, 16A), hypopharynx without distomedial projection (Figs 4F, 8I) ....................................................................................................................................... 6

5. Maxillary ventral canine not laterally folded over the canines (Fig. 12D); labial palp segment III wide (Fig. 12G) ................................................................................... R. uiara sp. nov. (Central Amazon)

– Maxillary ventral canine laterally folded over the canines (Fig. 1E); labial palp segment III narrow (Fig. 1G) ........................................ R. trichobasis Lugo-Ortiz & McCafferty, 1998 (Pampa Biome)

6. Patella-tibial suture on foreleg absent (Fig. 9A); outer arc of setae on glossae sinuous (Fig. 8K); distal lobe of maxillary palp segment II with half of width of segment II apex (Fig. 8D) .......................... .......................................................................................... R. oxum sp. nov. (Southwestern Amazon)

– Patella-tibial suture on foreleg present (17A); outer arc of setae on glossae not sinuous (Fig. 16G); distal lobe of maxillary palp segment II with the same width of segment II apex (Figs 4E, 16D) .... ........................................................................................................................................................... 7

7. Segment III of labial palp apically pointed (Fig. 4G); paraproct with nine to eleven marginal spines (Fig. 6B) ........................................................... R. amazona sp. nov. (Amazon in southern Roraima)

– Segment III of labial palp broadly pointed (Fig. 16F); paraproct with two marginal spines (Fig. 18B) ......................... R. naia sp. nov. (ecotone between Amazon forest and Roraima savanna)