Key to final instar nymphs of North American Neoephemera species

(modified from Bae & McCafferty 1998 and Berner 1956)

1 All legs with lengths subequal to each other (Fig. 1); tarsal claws sharply curved (Fig. 9); anterolateral projections rudimentary and anterosubmedian tubercles absent on pronotum (Figs 1 & 14) USA: North Carolina, Virginia............... N. eatoni

- Legs increase in length from pronotum to metanotum; tarsal claws gradually curved (Fig. 11); pronotum and mesonotum with moderate or well developed anterolateral projections (Figs 13 & 15–17).......................................... 2

2(1) Distinct, well developed pronotal anterolateral projections present (Fig. 13). Body 14–17 mm, eastern Nearctic USA: Georgia, North Carolina, South Carolina, Tennessee, Virginia, West Virginia..................................... N. purpurea

- Moderately developed anterolateral projections present on pronotum and mesonotum (Figs 15–17). Body 8–11 mm ....... 3

3(2) Small distinct anterosubmedian tubercles present on pronotum (Fig. 15). Rounded anterolateral projections present on mesonotum. Rudimentary rounded projections present posteromedially on abdominal terga VI–VIII, eastern Nearctic USA; Alabama, Florida, Georgia, North and South Carolina.................................................. N. youngi

- Pronotum with large, distinct anterosubmedian tubercles (Figs 16–17). Mesonotum with distinct pointed anterolateral expansions; distinct tubercles present posteromedially on abdominal terga VI–VIII...................................... 4

4(3) Anterosubmedian pronotal tubercles approximate and apically parallel to convergent (Fig. 16) USA: Florida and Georgia .............................................................................................. N. compressa

- Anterosubmedian pronotal tubercles well separated and apically divergent (Fig. 17) Canada: Quebec; USA: Indiana, Michigan (Bae & McCafferty 1998), Wisconsin (Schmude et al. 2012), and Virginia (CSU, see Additional Materials Examined)................................................................................................... N. bicolor