Key to genera of aquatic pupae of Nearctic Hemerodromiinae

1 Four bristle-like apical spines on terminal abdominal segment, 2 projecting dorsolaterally and 2 projecting ventrolaterally; femur of fore leg (visible through the pupal cuticle) thin, subequal in width to femur of middle and hind leg (Fig. 5) .......................................................................................................................................... Neoplasta Coquillett

- Two bristle-like apical spines on terminal abdominal segment, each projecting either posteroventrally or posterolaterally; femur of fore leg thick, width 2 x that of femur of middle and hind leg (Figs. 6–8) ....................................... 2

2 Two bristle-like apical spines on terminal abdominal segment projecting posteroventrally; pre-terminal abdominal segments with posterior row of several large spines; dorsal spines of terminal abdominal segment ca. 1/2 length of bristle-like apical spines (Fig. 6).............................................................................................. Hemerodromia Meigen

- Two bristle-like apical spines on terminal abdominal segment projecting posterolaterally; pre-terminal abdominal segments with posterior row of numerous small spines; dorsal spines of terminal abdominal segment no more than 1/ 5 length of bristle-like apical spines (Figs. 7–8)........................................................................................................... 3

3 Pre-terminal abdominal segments with posterior row of spines of nearly alternating longer and shorter lengths (Fig. 7); dorsal spines of terminal abdominal segment ca. 1/5 length of bristle-like apical spines (tend to get broken or dislodged on specimens in alcohol vials) .......................................................................................... Chelifera Macquart

- Pre-terminal abdominal segments with posterior row of short spines of uniform length (Fig. 8); dorsal spines of terminal abdominal segment ca. 1/10 length of bristle-like apical spines ....................................... Metachela Coquillett