Key to males of Pachyopsis

(excluding P. taracta Blocker and P. chilensis Linnavuori only known from females)

1. Aedeagus with ventral margin of aedeagus distinctly excavated (Figs 35, 54)...................................... 2

- Aedeagus with ventral margin of aedeagus not or slightly excavated (Fig. 73)..................................... 4

2. Aedeagus with apex acute (Fig. 54)................................................. P. nigrifacis sp. nov. (Brazil)

- Aedeagus with apex rounded (Fig. 35)..................................................................... 3

3. Ventral process of pygofer short, reaching the apical third of pygofer (Coelho 1999: 240, fig. 1); aedeagus with preatrium robust, not constricted near atrium (Coelho 1999: 240, fig. 2) (Brazil).............................. P. vicosensis Coelho

- Ventral process of pygofer long, almost reaching pygofer apex (Fig. 30); aedeagus with preatrium elongated, constricted near atrium (Fig. 35) (Brazil)................................................................. P. fasciatus sp. nov.

4. Aedeagus with ventral margin broadly rounded or straight (Fig. 73)............................................. 5

- Aedeagus with ventral margin with rounded protrusion on preatrium or base of shaft (Kramer 1963: 44, figs 13, 18)...... 11

5. Ventral process of pygofer long, almost reaching or surpassing the apex of pygofer (Freytag 2019: 345, fig. 5)........... 6

- Ventral process of pygofer distinctly short, not reaching the apex of pygofer (Fig. 68)............................... 8

6. Pygofer with ventral margin straight; ventral process of pygofer extending outside pygofer for half its length (Freytag 2019: 345, fig. 1) (Colombia)................................................................ P. colombiana Freytag

- Pygofer with ventral margin broadly rounded; ventral process of pygofer not extending outside pygofer or only its apex (Freytag 2019: 345, fig. 5).................................................................................. 7

7. More than 7 mm in length; ventral process of pygofer surpassing pygofer apex; (Freytag 2019: 345, fig. 5) (Colombia).......................................................................................... P. elongata Freytag

- Less than 6 mm in length; ventral process of pygofer not extending outside pygofer (Kramer 1963: 44, fig. 11) (Mexico and Guatemala)............................................................................. P. foratus Kramer

8. Aedeagus with ventral margin straight (Blocker 1982: 641, fig. 1) (Panama and Colombia)............ P. nomanus Blocker

- Aedeagus whit ventral margin broadly rounded (Fig. 73)...................................................... 9

9. Ventral process of pygofer upturned distally forming a right angle (Kramer 1963: 44, fig. 17) (Brazil)..... P. similis Kramer

- Ventral process of pygofer gradually recurved or slightly bent dorsad (Fig. 68).................................... 10

10. Less than 7 mm in length; ventral process of pygofer gradually recurved (Fig. 68); style with blade slightly curved dorsally (Fig. 72) (Brazil)............................................................................ P. pallidus sp. nov.

- More than 7 mm in length; ventral process of pygofer slightly bent dorsad (Freytag 2019: 345, fig. 8); style with blade straight (Freytag 2019: 345, fig. 5) (Peru and Bolivia)................................................. P. wappesi Freytag

11. Ventral process of pygofer hooked with apex curved ventrally (Kramer 1963: 44, fig. 19) (United States)..... P. laetus Uhler

- Ventral process of pygofer with a proximal, blunt, tooth-like expansion on distal portion (Kramer 1963: 46, fig. 14) (Ecuador)...................................................................................... P. calceus Kramer