Pollenia species Pollenia sp
Flies belonging to the genus Pollenia look much like ordinary flies. Most species are black, but softly glisten in the sunshine. That is because they have short, goldenbrown hairs on the thorax. The adults can be found on excrements, including those of humans. The larvae live a parasitic life in earth worms. In autumn the adults fly into our houses. They look for a place in attics to hibernate. Once hibernating the flies sit very still and it is almost impossible to wake them. They do no harm to you or your house, but can be a nuisance when appearing in great numbers. The fly in the top pictures certainly belongs to the Pollenia genus and could very well be Pollenia rudis. Pollenia rudis is the most common species in Central Europe. often appearing in buildings in large numbers, looking for a place to overwinter. So does the Autumn (or Face) Fly and various Blow Flies. Collectively these species are known as Cluster Flies or Clustering Flies. The larvae of Pollenia rudis are parasitic to certain earth worms. Grey Fleshflies may complete their life cycle in just two weeks, Pollenia rudis takes a whole year. So there is only one generation per year. In common English Pollenia rudis is known as the Attic Fly, the Loft Fly or the Buckwheat Fly. In the bottom pictures Pollenia flies we haven't been able to identify yet. Many species are extremely similar and you have to open them up to study the genitals in order to be able to tell the exact species.