Key to species of Plagaedessa

1. Gonocoxites 8 with distal margin strongly projected, reaching almost half the length of gonocoxites 8 (Fig. 38).................................................................................................. maranhensis sp. n.

- Gonocoxites 8 with distal margin weakly projected, reaching one third or less the length of gonocoxites 8 (Figs. 26, 31, 36)...................................................................................................... 2

2. Paramere with anterior projection subtriangular and long; posterior process short (Fig. 34).............. nigrovittata sp. n.

- Paramere with anterior projection short and rounded, posterior process long (Figs. 24, 29)............................ 3

3. Posterolateral angles of the pygophore straight (Figs. 23, 25); superior process of genital cup shallowly concave, small, not reaching both apices of the paramere (Fig. 24); Central America (Fig. 52)...................... celsa (Distant) n. comb.

- Posterolateral angles of the pygophore curved (Figs. 28, 30); superior process of genital cup deeply concave, large, reaching both apices of the paramere (Fig. 29); South America (Fig. 52)....................................... distanti sp. n.