Key to genera of Mythicomyiinae of the World

(modified from Rafael & Limeira-de-Oliveira (2014)) and to Brazilian species of Pieza

1 Antenna with one flagellomere; stylus distal, tiny, inconspicuous (visible only in higher magnification); postcranium produced, subequal to eye length............................................. Tamanduamyia Rafael & Limeira-de-Oliveira

- Antenna with two flagellomeres and stylus placed apically or subapically on second flagellomere; postcranium not produced2

2 Antenna with stylus placed apically on second flagellomere.................................................... 3

- Antenna with stylus placed subapically on second flagellomere................................................. 4

3 Vein A 1 complete, reaching wing margin; costal vein incomplete, ending between R 4+5 and M 1 veins................................................................................................. Mythenteles Hall & Evenhuis

- Vein A 1 short, incomplete, reaching alular incision level; costal vein circumambient... Mitinha Rafael & Limeira-de-Oliveira

4 Costal vein circumambient; cell dm fairly short, closed apically............................. Reissa Evenhuis & Baéz

- Costal vein incomplete, ending just beyond end of vein R 4+5; cell dm much longer than wide or open apically............ 5

5 Wing with well-developed keel-shaped anal lobe; vein separating basal cells not evident; males holoptic... Mythicomyia ... 6

- Wing with anal lobe normal, not keel-shaped; vein separating basal cells distinct, often well sclerotized; males dichoptic... 7

6 Males with secondary sexual character modifications on the legs (modified shapes of and notches in mid and/or hind legs and presence of pegs and large setae).......................................... Mythicomyia (Mythicomyia) Coquillett

- Males without secondary sexual character modifications of legs.................... Mythicomyia (Heterhybos) Brèthes

7 Wing with cell dm open, distal veins faint or effaced; head as wide as or wider than thorax......... Nexus Hall & Evenhuis

- Wing with cell dm complete; distal veins not faint; head usually narrower than thorax............................ Pieza Evenhuis. ........................................................................................... 8

8 Mesopleura brown to dark brown, with yellow areas on proepimeron, anepisternum, katepisternum and meron........... 9

- Mesopleura entirely brown, without yellow areas................................................ P. kake Evenhuis

9 Ejaculatory apodeme not oval medially (Figs 5, 14, 22, 31, 47, 56, 65).......................................... 10

- Ejaculatory apodeme oval medially (Fig. 39) in ventral view.................................. P. parnasecon sp. nov.

10 Gonostyli present (Figs 5–6, 14–15, 22–23, 31–32, 39–40, 56–57, 65–66)....................................... 11

- Gonostyli absent (Figs 47–48).............................................................. P. rafaeli sp. nov.

11 Pseudo-surstyli without strong setae (Figs 5, 14, 22, 31, 65) in ventral view...................................... 12

- Pseudo-surstyli with three strong setae (Fig. 56) in ventral view.................................. P. silvanae sp. nov.

12 Basiphallus about 1½–2.0X longer than distiphallus (Figs 15, 23, 32, 66); gonostylus not geniculate proximally in lateral view (Figs 14–15, 22–23, 31–32, 65–66)...................................................................... 13

- Basiphallus about ½ length of distiphallus (Fig. 6); gonostylus geniculate proximally in lateral view (Figs 5–6)................................................................................................... P. ankh sp. nov.

13 Gonostyli not trifurcate distally (Fig. 65)...................................................... P. yeatesi sp. nov.

- Gonostyli trifurcate distally (Figs 14, 22, 31).............................................................. 14

14 Cerci sub-hemispherical with distal end spiniform, pointed posteroventrally; gonostyli slender, exceeding posterior margin of epandrium (Fig. 15)................................................................... P. aurislepus sp. nov.

- Cerci oval without spiniform distal end pointed posteroventrally; gonostyli short, not exceeding posterior margin of epandrium (Figs 23, 32)........................................................................................ 15

15 Ejaculatory apodeme with sub-oval ventromedial projection in lateral view (Fig. 23); gonocoxites with anterior ventral margin not protuberant medially in anteroventral view (Fig. 24)...................................... P. bittencourti sp. nov.

- Ejaculatory apodeme with subquadrate ventro-medial projection in lateral view (Fig. 32); gonocoxites with anterior ventral margin protuberant medially in anteroventral view (Fig. 33).................................... P. parakake sp. nov.