1a corridor mine => 2

1b blotch mine, from which in the end a circular excision is made, almost as large as the blotch itself => 6

1c blotch without excision; no initial corridor => 7

1d tentiform mine => 11

1e fleck mine => 13

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

2a mine < 1 cm, containing much frass: Bucculatrix thoracella

2b mine longer, not containing so much frass => 3

3a mine upper surface, frass in two rows: “Agromyza alnibetulae”

3b mine full depth, frass in one central line => 4

4a mine long, over its entire length not wide than the larva itself; frass in a narrow central line. Egg not placed deeply in a vein axill: Stigmella microtheriella

4b mine shorter, wider, much wider than the larva; oviposition in a vein exill => 5

5a frass in the second half of the mine scattered, in grains: Stigmella floslactella

5b frass here in thick lumps (unsafe distinction): Stigmella carpinella

6a larva**: pronotum brown, meso- and metanotum each with a pair of dark spots: Incurvaria masculella

6b larva**: entire thorax dorsally yellowish-grey: Incurvaria pectinea

6c larva**: pronotum with a black plate: Incurvaria oehlmanniella

7a on the point of oviposition (almost always the leaf tip) a shining black drop of dried secretion: Trachys minutus

7b no such drop => 8

8a mine begins at the margin of the leaf; frass often in long threads; larva without feet => 9

8b mine begins more centrally; frass in loose granules; larva with feet => 10

9a larva: prothorax entirely white (occurrence on this host plant uncertain): Dyseriocrania subpurpurella

9b larva: pronotum with two irregular black spots: Paracrania chrysolepidella

10a silvery, upper-surface blotch: Phyllonorycter esperella (young mine)

10b small squarish brown blotch; older larva lives free, under a leaf fold: Parornix carpinella

11a mine upper-surface, not limited by lateral veins; starts as a flat, silvery blotch: Phyllonorycter esperella

11b mine lower-surface, between two lateral veins; 1 longitudinal fold => 12

12a cocoon generally without frass; cremaster with 2 pairs of hooks of almost equal size; exclusively on Carpinus: Phyllonorycter tenerella

12b cocoon generally incrusted with frass grains; exterior pair of cremaster hooks ca. 3 x as long and thick as the interior pair; rarely on Carpinus: Phyllonorycter messaniella

13a lobe case => 14

13b composite leaf case => 16

13c tubular leaf case => 18

13d spatulate laf case: Coleophora milvipennis (unusual on the host plant)

13e pistol case => 19

14a rear end of case strongly curved; mouth angle 60-80°: Coleophora fuscocuprella

14b case straight; mouth angle 0°: Coleophora violacea

15a the ringlets that are used to enlarge the case are cut from the upper epidermis of the lea: Coleophora violacea

15b these rings are cut from the lower epidermis: Coleophora ahenella

16a extension of the case by way of narrow rings appended to the mouth; case strongly curved: Coleophora serratella (youth case)

16b extension by way of pieces of plant cuticula; case straight => 17

17a old and new parts of the case of the same colour; cases in August-October: Coleophora orbitella

17b old and new parts differ in colour; cases in September-May: Coleophora binderella (unusual on this host plant)

18a case smooth, flattened-tubular with a narrow dorsal keel; April-June: Coleophora serratella (eindzak)

18b case zeppelin-shaped, untidy with attached leaf fragments; August-July: Coleophora siccifolia

19a case shining black, 7 mm: Coleophora anatipenella

19b case dull black, 9 mm: Coleophora currucipennella