1. Prementum cleft nearly halfway to its base; posterolateral margins of abdominal segments 9 and 10 without spines; lateral caudal gills flat or not strongly triquetal in cross section. . . . . . . . . . . . . . . . . . Calopteryx sp.
Prementum cleft only to base of palpal lobes; posterolateral margins of abdominal segments 9 and 10 with small, distinct spines; lateral caudal gills strongly triquetral in cross section. . . . . . . . . . . . . . . . . . Hetaerina sp.
