1. In lateral view, dorsal projections on mesonotal shield weekly to moderately developed, height less than, or subequal to, that of medial hump (Fig 2.1.1). . . . Baetisca lacustris
In lateral view, dorsal projections on mesonotal shield well developed, distinctly taller than medial hump (Fig. 2.1.2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Frontal projection well developed, distinctly extended beyond anterior margin of head (Fig. 2.1.3); ventral margins of mesonotal shield lack dark-brown outline; abdominal sternites 2-6 with prominent dark-brown spots near lateral margins . . . . . .Batisca obesa
Frontal projection developed, not extended beyond anterior margin of head (Fig. 2.1.4); ventral margin of mesonotal shield prominently outlined with dark-brown; abdominal sternites 2-6 lack prominent dark-brown sublateral spots but freckled with brown. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Batisca laurentina
Key to Ohio Baetisca Nymph Species
