Key to the European larvae of Myrmeleontidae
1 IX abdominal sternite of 2 nd and 3 rd instar with fossoria (Fig. 2A, 7)........................................ Palpares
- IX abdominal sternite without fossoria (Figs. 2, 3, 6).......................................................... 2
2 Mesothorax with a median tuft of hair-like setae; IX sternite conical, longer than wide; mesothoracic spiracle not raised on tubercle (Figs. 3A, 8)........................................................................... Dendroleon
- Mesothorax without a median tuft of setae; IX sternite wider than long (Figs. 3B–H)................................3
3 Mesothorax with pedunculated or sub-peduncolated setiferous processes (Fig. 1C)................................. 10
- Mesothorax with sessile setiferous processes only (Fig. 1B)....................................................4
4 External margin of the mandible with a fringe of long setae reaching the apical tooth; basal setae longer than the width of the mandible (Fig. 1B)....................................................................................5
- External margin of the mandible with a small basal group of setae, not reaching the apical tooth and shorter than the width of the mandible (Fig. 25).................................................................................. 9
5 The median tooth is the largest, IX sternite with prominent rastra (Figs. 2B–D, 21).................................. 6
- The apical tooth is the largest, IX sternite without prominent rastra (Figs. 6, 26).................................... 8
6 Median and apical mandibular teeth directly in contact, without setae between them (Fig. 21)............. Myrmecaelurus
- Median and apical mandibular teeth spaced by 1–2 setae (Fig. 22)...............................................7
7 IX sternite thickly covered with small digging setae, also disposed on the ventral surface of rastra.................................. Nohoveus (from Ábrahám & Papp 1990; Gepp 2010; Krivokhatsky 2011 and verified on non-European species)
- IX sternite covered with few very large digging setae, 1 large digging seta at the base of each rastrum (Figs. 2C–D)................................................................................................... Cueta (key 5)
8 Presence (exclusive or not) of spiniform or stout setae on the posterior margin of the VIII abdominal sternite (Figs. 6A–H)... Myrmeleon (key 6)
- Posterior margin of the VIII abdominal sternite exclusively covered by hair-like setae (Fig. 6I)................. Euroleon
9 Anterior margin of the labrum with a pronounced rounded lobe; mandibles swollen at the base; VIII sternite covered with digging setae (Fig. 24).......................................................................... Acanthaclisis
- Anterior margin of the labrum without a lobe; mandible not swollen; VIII sternite without digging setae (Fig. 25)... Synclisis
10 VIII abdominal sternite with prominent odontoid processes (Figs. 3B–F).........................................11
- VIII abdominal sternite without or with very reduced odontoid processes (Figs. 3G–H)............................. 15
11 Dorsal surface of the head and pronotum covered by white scale-like setae (Figs. 4B, 9)....................... Nemoleon
- Dorsal surface of the head and pronotum covered by dark bristle-like setae (Figs. 4C–H)............................ 12
12 IX sternite with an anterior group of ventral digging setae; mandibles very robust; basal and median teeth closer to each other than to the distal tooth (Figs. 3D, 10)............................................................... Creoleon
- IX sternite without an anterior group of ventral digging setae, mandibles comparatively slender, teeth equidistant (Figs. 3E–F). ................................................................................................... 13
13 Pronotum with 4 dorsal parallel series of large setae (Figs. 4F, 11).................................... Macronemurus
- Pronotum without distinct dorsal parallel series of setae (Figs. 4C, E)........................................... 14
14 Pronotum covered by long setae interspersed by short spiniform ones; rastra of IX sternite with digging setae of similar size (Figs. 3C, 4C, 12)........................................................................ Distoleon (key 2)
- Pronotum covered by long setae interspersed by dolichasters; rastra of IX sternite with inner digging seta long a half of the longest pair (Figs. 3E, 4E)................................................................... Neuroleon (key 3)
15 Distance between the base of the mandible and the basal tooth longer than that between the basal and apical teeth; median and apical teeth equal sized; rastra of IX sternite with inner digging seta long a half the others (Figs. 3H, 20)...... Gymnocnemia
- Distance between the base of the mandible and the basal tooth shorter than that between the basal and apical teeth; apical tooth larger than the median tooth; rastra of IX sternite with inner digging seta long less than a third the others (Figs. 4G, 18)........................................................................................... Megistopus (key 4)