I don't really know what's going on here. A big mite (4mm!) feeding(?) on a crane fly(?) larva.
There is a kind of mite - Calyptostoma - that specifically parasitises crane flies: the young mites cling to adult crane flies while the adult mites feed on crane fly larvae - like this?
I haven't found much information on them yet, though.
iNaturalist observation 267018079













