Key to the known species of Tapajosa (modified from Young 1968)

1. Hindwing with vein R 2+3 complete................................................................ T. doeringi

- Hindwing with vein R 2+3 incomplete...................................................................... 2

2. Aedeagal processes twice-branched at base.......................................................... T. spinata

- Aedeagal processes not as above......................................................................... 3

3. Aedeagal processes unbranched................................................................... T. ocellata

- Aedeagal processes branched............................................................................ 4

4. Aedeagal processes with two subequal branches at apex, basal branches not recurved................... T. fulvopunctata

- Aedeagal processes, if branched apically, with rami unequal and dissimilar, basal branches directed proximally........... 5

5. Aedeagal processes strongly recurved apically, directed cephalad......................................... T. similis

- Aedeagal processes not so.............................................................................. 6

6. Aedeagal processes short, ± same length as aedeagal shaft....................................... T. rubromarginata

- Aedeagal processes long, more than twice the length of the aedeagal shaft......................... T. arawaka sp. nov.