Key to nymphs of the genera of Notonectidae occurring in Brazil

1a. Labrum rounded......................................................................... Buenoa Kirkaldy

1b. Labrum triangular..................................................................................... 2

2a (1b). Middle femur without anteapical pointed protuberance.......................................... Martarega White

2b. Middle femur with anteapical pointed protuberance........................................................... 3

3a (2b). Anterolateral margins of pronotum foveate................................................. Enitharoides Brooks

3b. Anterolateral margins of pronotum straight.................................................. Notonecta Linnaeus