Key to males of Neotropical Atrichopogon with pigmented wings

(Excluding Atrichopogon nebulosus Macfie and A. nubeculosus Macfie known only as females)

1. Wing with distinct spots of pigmentation (Figs. 2C, 2F, 4C, 4F)................................................. 2

- Wing without distinct spots of pigmentation......................................... other 102 spp. of Atrichopogon

2. Wing with two distinct darker spots, one over r-m and second in cell r 3 posterior to apex of R 3 (Figs. 2C, 2F, 4C, 4F)....... 3

- Wing with extensive darker spots........................................................................ 10

3. Gonostylus double or forked (Figs. 3A, 3B, 5A, 6B, 6E, 6H)................................................... 4

- Gonostylus single, not forked (Figs. 6A, 6D, 6G)............................................................ 8

4. Gonostylus double (Figs. 6B, 6E)......................................................................... 5

- Gonostylus forked (Figs. 3A, 3B, 5A, 6H).................................................................. 6

5. Posterior margin of tergite 9 rounded, not surpassing apex of gonocoxite; sternite 9 with lateral group of scattered setae (Fig. 6B).......................................................................... casali Cavalieri & Chiossone

- Posterior margin of tergite 9 elongated as a setose finger-like process, greatly surpassing apex of gonocoxite; sternite 9 with transverse row of setae (Fig. 6E)........................................................ dactilus Felippe-Bauer

6. Inner portion of gonostylus divergent from outer portion, needle-shaped (Fig. 6H)................... pictipennis Clastrier

- Inner portion of gonostylus not divergent and needle-shaped................................................... 7

7. Gonostylus forked near midlength (Fig. 3B)..................................................... nukini sp.nov.

- Gonostylus forked near its base (Fig. 5A).................................................... shawadaua sp.nov.

8. Posterior margin of tergite 9 with a small median lobe (Fig. 6D).......................... clastrieri Spinelli & Marino

- Posterior margin of tergite 9 rounded or bifid................................................................ 9

9. Posterior margin of tergite 9 bifid; posterior margin of sternite 9 strongly concave forming two lateral lobes, each with scattered setae; gonostylus tapered and curved with pointed apex (Fig. 6A)...................... bicuspis Borkent & Picado

- Posterior margin of tergite 9 rounded, posterior margin of sternite 9 without lobes, with middle row of setae; gonostylus thick with blunt apex (Fig. 6G).............................................................. ornatipennis Clastrier

10. Distal 1/3 of the wing dark with two elliptic pale spots, one subapically in r 3 and another extending from apical portion of m 1 to m 2; gonostylus gradually tapering and curved, bearing pointed apex (Fig.6C)...................... cavus Felippe-Bauer

- Entire distal 1/3 of the wing dark; gonostylus thick with two pointed apical prongs (Fig.6F).......... maculipennis Clastrier