| 1 | a Head and thorax mostly reddish (Fig. 17A, B). |
| b Abdomen dorsally mostly black (Fig. 17A). |
| c Frontal area between antennae protruding less abruptly below (Fig. 5I) |
| d Arctic species | 2 |
| - | aa Head and thorax mostly yellowish to mostly black (pale parts can be green in life) (e.g. Figs 4, 14A-D) |
| bb Abdomen completely pale to dorsally mostly black (pale parts usually green in life) (e.g. Figs 4, 14C, 20A) |
| cc Frontal area between antennae protruding more abruptly below (Fig. 5J)dd Temperate and arctic species | 3 |
| 2(1) | a Dorsal margin of lancet angulate at about second or third serrula from apex, apical sutures distinctly inclined apically (Fig. 6B) |
| b Valvula 3 in dorsal view narrow (Fig. 5B) | E. leptocephalus (Euura bergmanni group) |
| - | aa Dorsal margin of lancet not angulate at about second or third serrula from apex, apical sutures not distinctly inclined apically (Fig. 7A) |
| bb Valvula 3 in dorsal view usually broad at base (Fig. 5C, D) | similar species mostly in Euura flavescens group (E. reticulata, E. lienterica in part, E. pallidior ...) |
| 3(1) | a Tip of lancet rather broad and dorsally abruptly narrowing (Fig. 8A-C) or broad and round (Fig. 8D) |
| b Serrulae apically protruding and / or with large microdenticles (Fig. 8) |
| c Malar space 1.5-2.2 times as long as diameter of front ocellus (Fig. 5K, O) | 4 |
| - | aa Tip of lancet usually narrower, acute, and dorsally narrowing less abruptly (Figs 6A, 9) |
| bb Serrulae apically not protruding and with small microdenticles (Figs 6A, 9) |
| cc Malar space 1.1-2.0 times as long as diameter of front ocellus (Fig. 5L-N, P) | 7 |
| 4(3) | a Valvula 3 in lateral view shorter (Fig. 5F) |
| b Lancet shorter and broader (Fig. 8D) | E. brevivalvis |
| - | aa Valvula 3 in lateral view longer (Fig. 5G) |
| bb Lancet longer and narrower (Fig. 8A-C) | 5 [the following three species not definitely morphologically separable] |
| 5(4) | a Slightly larger denticles of serrulae (uncertain) (Fig. 8A) | E. dispar |
| - | aa Slightly smaller denticles of serrulae (uncertain) (Fig. 8B, C) | 6 |
| 6(5) | a On Betula (morphological differences unknown) | E. viridis |
| - | aa On Alnus (morphological differences unknown) | E. glutinosae |
| 7(3) | a Ventral part of 2nd to 4th suture of lancet oblique and more or less straight or weakly curved apically (Fig. 9C) |
| b Gap between serrulae relatively large (Fig. 9C) |
| c Head dorsally more rounded (Fig. 5Q) | E. respondens |
| - | aa Ventral part of 2nd to 4th suture of lancet in most cases weakly or distinctly curved basally (Figs 6A, 9A, B, D) |
| bb Gap between serrulae large or small (Figs 6A, 9A, B, D) |
| cc Head dorsally rounded or rectangular (Fig. 5R-T) | 8 |
| 8(7) | a Lancet usually relatively broad (Fig. 6A) |
| b Sutures of basal annulets usually weakly bent (Fig. 6A) |
| c Gap between serrulae small, relative to length of serrulae (Fig. 6A) | E. bergmanni |
| - | aa Lancet narrower (Fig. 9A, B, D) |
| bb Sutures of basal annulets distinctly bent (Fig. 9A, B, D) |
| cc Gap between serrulae small or large, relative to length of serrulae (Fig. 9A, B, D) | 9 |
| 9(8) | a Malar space more than 1.4 times as long as diameter of front ocellus (Fig. 5P) |
| b Clypeus usually less deeply emarginate (Fig. 5P) |
| c Head in dorsal view more rectangular (Fig. 5S) | E. sylvestris |
| - | aa Malar space less than 1.5 times as long as diameter of front ocellus (Fig. 5L) |
| bb Clypeus usually more deeply emarginate (Fig. 5L) |
| cc Head in dorsal view more rounded (Fig. 5T)... Euura oligospila group | 10 |
| 10(9) | a Gap between serrulae smaller compared to length of serrulae (Fig. 9A) |
| b Terga 1-8 dorsally usually completely black (Fig. 21E) | E. frenalis |
| - | aa Gap between serrulae larger compared to length of serrulae (Fig. 9B) |
| bb Terga 1-8 dorsally usually nearly completely pale or with narrow black median line (Fig. 21A) | E. oligospila |