Key to males of Platyplastinx

The type species, P. solox, is described only from females.

1 Cerci each with more than one elongated tenaculum, 2 to 8 times longer than the rod-like accessory tenacula............. 2

- Cerci each with only one elongated tenaculum, 2 to 8 times longer than the rod-like accessory tenacula (Figs. 6D; 8D)..... 4

2 Eye bridges contiguous; elongated tenacula numbering three, accessory tenacula numbering five..... P. sycophantos (Quate)

- Eye bridges separated; elongated tenacula numbering 12 to 15, accessory tenacula numbering 10 or 20.................. 3

3 Eye bridges separated by 1.5 facet diameters, interocular suture having inverted Y-shape; accessory tenacula numbering 20............................................................................. P. crossomiscos Quate & Brown

- Eye bridges separated by less than one facet diameter, interocular suture slightly curved; accessory tenacula numbering 10................................................................................. P. culmosus Quate & Brown

4 Cercus pyriform, wider at base, narrowing to the apex, which is tapered (Figs. 2C).................................. 5

- Cercus not pyriform, having other shapes, apex never tapered (Figs. 6D; 8C–D).................................... 8

5 Eye bridge with three facet rows; accessory tenacula numbering five........................... P. obscurus comb. nov.

- Eye bridge with four facet rows (Figs. 1A; 3A); accessory tenacula numbering 6 to 7, 9 or 16–18...................... 6

6 Cercus with accessory tenacula numbering 16–18 (Fig. 4C)................................... P. duckhousei sp. nov.

- Cercus with accessory tenacula numbering 6 to 9............................................................ 7

7 Eyes separated by less than one facet diameter; accessory tenacula numbering 6 to 7 (Fig. 2C)....... P. amazonensis sp. nov.

- Eyes separated by one facet diameter; cercus with 9 accessory tenacula.................... P. apodastos Quate & Brown

8 Cercus with accessory tenacula numbering 14 to 15............................................ P. hirsutus sp. nov.

- Cercus with accessory tenacula numbering 2 to 8............................................................ 9

9 Eye bridges contiguous; accessory tenacula numbering 4; M2 incomplete at base................. P. tango Quate & Brown

- Eye bridges separated by 0.5 facet diameters; accessory tenacula numbering 2 to 8; M2 complete, or incomplete at base.... 10

10 M2 complete; accessory tenacula numbering 2 (Fig. 6D)......................................... P. exiguus sp. nov.

- M2 incomplete; accessory tenacula numbering 3 to 8......................................................... 11

11 Cercus with accessory tenacula numbering 3................................................. P. moragai (Quate)

- Cercus with accessory tenacula numbering 6 to 8............................................. P. plumaris (Quate)