1a blotch mine without preceding corridor; after a short while the larvae live free between spun leaves: Scrobipalpa artemisiella

1b mine is or begins with a gallery => 2

1c fleck mine => 3

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

2a gallery, in the same leaf continued as a blotch: Phytomyza thymi

2b gallery, in a different leaf continued as a blotch: Glaucolepis thymi

3a larva mines from a long silken tube, attached to the plant, into which it can retreat when endangered or during feeding pauses => 4

3b larva mines from a spinning that holds several leaves together: Sophronia humerella

3c larva mines from a transportable case => 5

4a larva grey-green with whitish length lines: Scythris picaepennis

4b larva dark purple with whitish transverse bands: Scythris siccella

5a the case, that is covered with much frass, has an irregular shape: Vulcaniella grabowiella

5b a typcial Coleophora case =>6

6a lobe case: Coleophora struella

6b seed case: Coleophora lixella

6c sheath case => 7

6d composite leaf case => 8

6e tubular silken case: 9

7a larva: metanotum colourless: Coleophora niveicostella

7b metanotum with two dark shields (occurence on thyme uncertain): Coleophora albitarsella

8a mouth angle ± 90°: Coleophora serpylletorum

8b mouth angle ± 45°: Coleophora obtectella

9a case 6-7 mm: Coleophora pyrenaica

9bcase 8-9.5 mm: Coleophora thymi & tolli.