1a mine ends upon a circular excision: Tachyerges decoratus

1b tentifrom mine => 2

1c upper- or lower-surface blotch => 8

1d full depth blotch => 16

1e corridor => 25

1f full depth corridor that widens so quickly that it can just as well be called a triangular blotch; a elliptic larva always present in the mine: Rhamphus pulicarius

1g very long corridor in the bark of a young twig, ending upon a white upper-surface cocoon at the very base of a leaf: Phyllocnistis canariensis, Ph. ramulicola

1h fleck mine => 32

1i galls, etc => Tables for all parasites per species

2a mine < 8 mm; larva later living free under a folded leaf margin: Caloptilia stigmatella

2b mine > 15 mm, pupation in the mine => 3

3a on creeping willow: Phyllonorycter quinqueguttella

3b on sallows => 4

3c on narrow-leaved willows => 5

4a pupa in a tough, golden or gold-brown cocoon: Phyllonorycter dubitella & Ph. hilarella

4b cocoon thin, white or pale yellow: Phyllonorycter salicicolella

5a pupa not in a cocoon; cremaster with 1 pair of spines; only on Osier: Phyllonorycter viminetorum

5b pupa in a (sometimes thin) cocoon; cremaster with 2 pairs of spines => 6

6a pupa: cremaster smooth; thorns minute, barely visible even under a microscope: Phyllonorycter pastorella

6b cremaster surface rough; thorns not that small => 7

7ainner pair of thorns pointing upwards: Phyllonorycter connexella

7b inner pair of thorns pointing inwards: Phyllonorycter salictella

8a mine black or brown-black => 9

8b mine paler => 13

9a on top of the mine, near a vein, a group of flat, glistening egg shells: Leucoptera sinuella

9b no egg shells to be seen => 10

10a in fresh mines feeding lines well visible; larva a maggot: Agromyza albitarsis

10b no feeding lines apparent; larva with chitinised head => 11

11a mine large; oviposition scars recognisable as light brown transparant points ( Zeugophora-species, difficult to identify) => 12

11b lmine 1-2 cm; no oviposition scars visible: Isochnus sequensi, I. angustifrons, & I foliorum

12a larva: pronotum with 6 pairs of setae: Zeugophora flavicollis

12b pronotum with 9 pairs of setae: Zeugophora subspinosa

13a oviposition site (almost always the leaf tip) covered by a shining black drop of hardened secretion: Trachys minutus

13b no such drop => 14

14a mine > 10 mm, young pale green, larva a maggot => 15

14b mine < 8 mm, silvery, rusty brown or brown; larva with chitinised head: Caloptilia stigmatella

15a Mediterranean species; larva: cephalic skeleton of Agromyzinae type: Japanagromyza salicifolii

15b western and central European species; cephalic skeleton of Phytomyzinae type: Aulagromyza tridentata

16a mine begins at a globular shining black egg shell => 17

16b no egg shell visible => 19

17a primary blotch, always against the midrib (in fact beginning within the midrib); egg on the midrib; frass in two diverging lines, forming a V-pattern; often in a green island: Ectoedemia intimella

17b secondary blotch, free from the midrib; frass not in a V => 18

18a on Sallows: Stigmella salicis

18b on Creeping Willow: Stigmella zelleriella

19a mine begins as a triangle, pressed against the midrib; frass in two diverging lines; often in a green island: Ectoedemia intimella

19b mine free from the midrib, frass not in a V => 20

20a larva without stemmata; pupation in the mine, in a globular cocoon => 21

20b larvae with one (more?) stemmata; a cocoon, if present, never globular => 22

21a oviposition in the midrib or a thick lateral vein: Tachyerges salicis

21b oviposition in the leaf disc, not in midrib or thick vein: Tachyerges rufitarsis

22a mine in early spring; larvae communal; older larvae live free in a common web: Yponomeuta rorrella

22b mine later; larva single, remaining in the mine till (close before) pupation => 23

23a pupa in the mine, in a disc-shaped cocoon; mine a primary blotch, extending from the leaf tip, occupying the entire width of the leaf; larva: feet reduced to short stumps: Heterarthrus microcephalus

23b pupation external; blotch mine does not start from the tip of the leaf; larva with relatively slender feet => 24

24a larva with a lateral black spot on each abdominal segment; mountain species, on all sorts of Salix: Scolioneura tirolensis

24b larva without a row of lateral spots; lowland species on Salix viminalis: Fenusella wuestneii

24c larva without a row of lateral spots; lowland species on Salix lapponum: Fenusella septentrionalis

25a gallery of normal depth, greenish, entirely limited to the lamina => 26

25b gallery epidermal, silvery of yellowish, partly running over the petiole and bark => 31

26a corridor upper- or lower-surface => 27

26b corridor full depth => 28

27a corridor broad: Agromyza salicina

27b corridor remarkably slender: Aulagromyza fulvicornis

28a mine begins at a shining-black globular egg shell => 29

28b no egg shell visible here => 30

29a on Sallows: Stigmella salicis

29b on Creeping Willow: Stigmella zelleriella

29c on other Willows: Stigmella obliquella

30a mine begins at the base of the midrib, ending at globular cocoon in which pupation takes place: Tachyerges pseudostigma & T. stigma

30b mine begins at the leaf tip, descends along the leaf margin, and ends upon a circular excision: Tachyerges decoratus

30c mine winds freely through the leaf: Lyonetia clerkella

31a gallery yellowish, frass line narrow, sharp: Phyllocnistis valentinensis

31b gallery silvery, frass line broader, less sharply defined: Phyllocnistis saligna

32a lobe case: Coleophora potentillae

32b composite leaf case: Coleophora lusciniaepennella

32c pistol case => 33

33a ‘handle’ of the pistol with ear-like appendages: Coleophora currucipennella

33b no such appendages => 34

34a case at either side with grey side-whiskers out of plant hair: Coleophora albidella

34b no side-whiskers => 35

35a case shining black; common, polyphagous species: Coleophora anatipenella

35b case greyish; rare species, only on narrow-leaved Willows: Coleophora zelleriella