Key to the species of Alasagenia from Brazil (females)

1 Forewing mostly darkened or yellow, without two distinct dark bands............................................ 2

- Forewing mostly hyaline or subhyaline, with two distinct dark bands............................. A. erichsoni (Banks)

2 Presence of golden setae on the integument of the head and mesosoma........................ A. curtispinus (Cameron)

- Absence of golden setae on the integument................................................................. 3

3 Forewing entirely darkened with purple reflections............................................ A. difformis (Banks)

- Forewing not fully darkened, without purple reflections....................................................... 4

4 Forewing darkened, except by the partially hyaline cells 1M, 2Cu and 2M; hindwing hyaline, except by anterior margin which is darkened and the apex that is slightly darkened; antennae black.................................. A. cursor (Smith)

- Forewing yellow, median portion darkened, apex lighter; hindwing dull yellow; antennae black, antennal segment seven yellow............................................................................. A. flavipennis (Banks)