Determination key for Larvae of Malachiidae to the level of genera and sometimes species in B. Klausnitzer, "Die Larven der Käfer Mitteleuropas" Vol. 3 Fischer Verl. Jena-Stuttgart 1996

Sounds like Anthocomus coccineus to me - but the Die Käfer Mitteleuropas Larven vol3 suggested earlier will help you for sure.

Thanks a lot. I try to use Klausnitzer and then we'll see :-)

Malachiidae larvae associated with reed galls? For me, this is an important puzzle stone for their ill known biology!!

@ Petr Bogusch: Did you had a result of determination or publications on this?

I recall two papers shedding light on the gall association in Melyridae sensu lato:

http://www.sea-entomologia.org/Publicaciones/PDF/BOLN45/109_121BSEA45JuniperChalcids.pdf

and

http://edepot.wur.nl/347358