Key to species of Porphyrochroa from the Amazon Basin, Brazil, based on males.

1. Mid tibia without long slender dorsal setae; mid basal tarsomere without long posterodorsal setae; tergite 7 without pair of posteroventral protuberances (Fig 13a); sternite 8 divided longitudinally in two narrow plates widely separated (Fig. 13b); hypandrium reduced in size (Figs. 13c; e)..........................................2

- Mid tibia with long slender dorsal setae; mid basal tarsomere with long posterodorsal setae; tergite 7 with pair of posteroventral protuberances (Fig 2a); sternite 8 entire (Fig. 2b); hypandrium normal (not reduced).....................................................................................................................................................................3

2. Midlegs simple, without modifications ...................................................................................... P. elongata

- Modified midlegs, with projections on the tarsomeres (Fig. 13i)........................... P. platypoderis sp. nov.

3. Anterior lobe of cercus projected to the apex (Fig. 4g); posterior lobe wide (Fig. 4g).............................. 4

- Anterior lobe of cercus projected to the base (Figs. 7g; 15g); base of posterior lobe narrow (Figs. 7g; 15g); subepandrial sclerite with arms usually convergent (Fig. 8i); sternite 7 inclined in lateral view (Fig. 11c).....................................................................................................................................................................5

4. Anal lobe of wing weakly developed; hind femur without row of anteroventral spines P. hipandriociliaris

- Anal lobe of wing well developed (Fig. 18 d); hind femur without row of anteroventral spines .................. ............................................................................................................................ P. cercosingularis sp. nov.

5. Ejaculatory apodeme with four projections (Fig. 14f); hind tibia with long dorsal setae...........................6

- Ejaculatory apodeme with three projections (Fig. 3f); hind tibia usually without long dorsal setae; mid tibia with long posterodorsal setae ............................................................................................................. 7

6. Hypandrium without setae (Fig. 14d; g); acrostichal setae absent; mid tibia with long slender setae .......... ........................................................................................................................... P. quadrilamelaris sp. nov.

- Hypandrium with setae in posterior region; acrostichal setae reduced (one or two pair); mid tibia without long slender setae ............................................................................................................................. P. vidali

7. Cercus with bifid apex (Figs. 3h; 5h).........................................................................................................8

- Cercus with simple apex (Fig. 6h).............................................................................................................. 9

8. Tergite 8 with narrow posterior projection (Fig. 3a); sternite 7 square, without lateral projections (Fig. 3b) ............................................................................................................................................ P. bifida sp. nov.

- Tergite 8 without narrow projection at apex (Fig. 5a); sternite 7 with lateral projections (Fig. 5b) ............. ................................................................................................................................... P. dactiloides sp. nov.

9. Mid basal tarsomere with long dorsal setae; anal lobe of wing well developed (Fig. 18 c).......................10

- Mid basal tarsomere without long posterodorsal setae; anal lobe of wing usually weakly developed (Fig. 18 a)............................................................................................................................................................12

10. Semi-circular epandrium in lateral view (Figs. 10; 16e)...........................................................................11

- Subtriangular epandrium in lateral view (Fig. 17e)......................................................... P. xavieri sp. nov.

11. Subepandrial sclerite with fold at arm apex (Fig. 16i) ................................................... P. s i m p l e x sp. nov.

- Subepandrial sclerite without fold at arm apex (Fig. 10i) ......................................... P. manauara sp. nov.

12. Hind femur with row of anteroventral and posteroventral spines .............................................................13

- Hind femur without row of anteroventral spines......................................................................................16

13. Cell dm widened apically in comparison with the base (Figs. 18 a; f); sternite 5 modified, with projections and setae.....................................................................................................................................................14

- Cell dm narrowed apically in comparison with the base (Figs. 18 h; 19b); sternite 5 normal...................15

14. Mild curve at apex of vein R2+3 beneath pterostigma (Fig. 18 f); hypandrium with setae (Fig. 6d; g); sternite 5 as Figures 6b; c ........................................................................................................... P. distincta sp. nov.

- Accented curve at apex of vein R2+3 beneath pterostigma (Fig. 18 a); hypandrium without setae (Fig. 1d; g); sternite 5 as Figures 1b; c ............................................................................................ P. aliena sp. nov.

15. Hind tibia with four posteroventral basal spines ............................................................ P. grandis sp. nov.

- Hind tibia without four posteroventral basal spines ................................................... P. pacaraima sp. nov.

16. Cercus with internal ventral downward projection in dorsal view (Fig. 2i)..............................................17

- Hind tibia with long slender dorsal setae; subepandrial sclerite with arms divergent (Fig. 15g).................. .................................................................................................................................. P. roraimensis sp. nov.

17. Hind femur with ventral spine; epandrium with digitiform projection superiorly (Figs. 2c; 9d)............. 18

- Hind femur without ventral spine.............................................................................................................19.

18. Hind tibia without long slender setae ......................................................................... P. amazonica sp. nov.

- Hind tibia with long slender setae ............................................................................... P. longiseta sp. nov.

19. Epandrium projected anteriorly and superiorly, with setae on dorsal region (Fig. 7e); hypandrium without setae (Figs. 7d; h); hind tibia without long slender setae; anal lobe of wing well developed (Fig. 18 g) ..... ...................................................................................................................................... epandrialis sp. nov.

- Epandrium subsquare (Fig. 11e); hypandrium without setae and apex with three projections in dorsal view (Fig. 11f); hind tibia with four pairs of long dorsal setae; hind basal tarsomere with two long dorsal setae; mid basal tarsomere with two anteroventral spine in basal region.................................. P. n e b l i n a sp. nov