Key to males of Piaroa and Colombiazomus*

1 Fixed cheliceral finger with a conspicuous distal accessory teeth (fig. 1)............................(Colombiazomus*)

- Fixed cheliceral finger without a conspicuous accessory teeth (fig. 2).....................................2 (Piaroa)

2 Flagellum lanceolate, without a defined bulb, (no constriction present between the bulb and lobe of the flagellum) (figs 3,5) 3

- Flagellum with a defined bulb present on the distal region (marked constriction between the bulb and lobe of the flagellum) (figs 7,9,11,13)....................................................................................... 4

3 Bulb of flagellum with two dorsal holes clearly visible (figs 3,4); posterior lobe 1.4 times longer than the bulb; ratio flagellum length/flagellum width 3.0..................................................................... P. villarreali

- Bulb of flagellum with the two dorsal holes slightly visible (figs 5,6); posterior lobe 1.9 times longer than the bulb; ratio flagel- lum length/flagellum width 2.5..................................................................... P. hoyosi

4 Posterior lobe of the flagellum with convergent margins (figs 7, 9, 15–16)......................................... 5

- Posterior lobe of the flagellum with parallel margins (figs 11,13)................................................ 7

5 Ratio flagellum length/flagellum width about 2.7 (figs15–17)............................................... P. pioi

– Flagellum short, ratio flagellum length/flagellum width between 2.0 and 2.3 (figs 7,9)............................... 6

6 Dorsal low holes of the flagellum fused (figs 7,8)..................................................... P. bijagua

- Dorsal low holes of the flagellum separated (figs 9,10)................................................. P. youngi

7 Flagellum more than 6 x longer than broad; seta dm1 located on the pedicel (Figs 11,12)...................... P. virichaj

- Flagellum less than 6 x longer than broad; seta dm1 located on the base of the bulb (Figs 13,14).............. P. guipongai * Colombiazomus is included because the similarity between flagellum of both genera can lead to misidentifications. In order to distinguish between the different species on the genus Colombiazomus see Armas and Delgado-Santa (2013).