Key to genera of aquatic larvae of Nearctic Hemerodromiinae

1 Terminal abdominal segment ending in a pair of prominent, divided apical lobes; terminal pair of prolegs at least 2 x longer than preceding 6 pairs (Figs. 1 a, 1b) ............................................................................ Hemerodromia Meigen

- Terminal abdominal segment lacking apical lobes; terminal pair of prolegs 1.5– 2 x longer than preceding 4 pairs (anterior 2 pairs may be shorter yet) (Figs. 2–4) ......................................................................................................... 2

2 Body robust, prolegs long and robust (Fig. 2 a), crochets prominent relative to couplet 2- below (see description for actual measurements and ratios); terminal abdominal segment ending in two very small, but distinctly separated processes, each of which bears a pair of setae (Fig. 2 b) ................................................................... Neoplasta Coquillett

- Body slender, prolegs short and slender (Figs. 3 a, 4a), crochets less prominent relative to couplet 2 above (see description for actual measurements and ratios); terminal abdominal segment ending in two pairs of setae that do not arise from distinctly divided processes (Fig. 3 b, 4b) .................................................................................................... 3

3 Setae on terminal abdominal segment and longitudinal cuticular striations strongly developed relative to couplet 3- below (see diagnosis section for explanation and interpretation) (Fig. 3 a) ................................... Chelifera Macquart

- Setae on terminal abdominal segment and longitudinal cuticular striations weakly developed relative to couplet 3 above (see diagnosis section for explanation and interpretation) (Fig. 4 a) ................................ Metachela Coquillett