
Appearance
The caterpillars feed on birches and oaks. The full grown larva lives in a black pistol case of about 7 mm long. The mouth angle is about 80°. From the rear end a grey silken cloak hangs down to almost halfway the mouth.Info on Coleophora identifcation based on case appearance:
Patzak, Helmut (1974) Beiträge zur Insektenfauna der DDR: Lepidoptera — Coleophoridae. - Beitr. Ent., Berlin, vol.24(5/8), pp.158-278.
https://www.zobodat.at/pdf/Beitraege-zur-Entomologie_24_0153-0278.pdf
The cases of Coleophora ibipennella and Coleophora anatipennella look quite similar (figs.39 & 40, pg.179) yet Coleophora ibipennella is more likely to occur on oak. Additional visual comparison:
http://www.lepiforum.de/lepiwiki.pl?Coleophora_Ibipennella
http://www.lepiforum.de/lepiwiki.pl?Coleophora_Anatipennella
References:
Some text fragments are auto parsed from Wikipedia.
https://www.zobodat.at/pdf/Beitraege-zur-Entomologie_24_0153-0278.pdf