Rod Williams / Thick-headed fly (Conops ceriaeformis) female, Brockley Cemetery, Lewisham, London, UK. August

Rod Williams / Thick-headed fly (Sicus ferrugineus) on Ragwort Grooming Brockley Cemetery, Lewisham, London, UK. August

Nick Upton / Thick-headed fly (Physocephala rufipes), a parasite of bees, feeding on Japanese mock orange flowers (Pittosporum tobira), Lesbos/ Lesvos, Greece, May.

Rod Williams / Thick-headed flies (Sicus ferrugineus) mating pair on Wild marjoram (Origanum vulgare) Hutchinson's Bank, New Addington, London, UK August

Rod Williams / Thick headed fly (Physocephala rufipes) feeding on Black knapweed (Centaurea nigra) flower, Sutcliffe Park, Eltham, London, England, June.

Jussi Murtosaari / Flies (Brachycera) on leaf, Parikkala, Etela-Karjala / South Karelia, Etela-Suomi / South Finland, Finland. June

Jussi Murtosaari / Fly (Brachycera) on Lily of the Valley berries, Parikkala, Etela-Karjala / South Karelia, Etela-Suomi / South Finland, Finland. September

Rod Williams / Thick-headed / Conopid fly (Sicus ferrugineus) feeding on ragwort, Lewisham, England, UK, August.

Rod Williams / Thick-headed / Conopid fly (Sicus ferrugineus) pair mating on ragwort, Lewisham, London, UK, July.

Rod Williams / Thick-headed / Conopid fly (Sicus ferrugineus) covered in ragwort pollen, Lewisham, London, UK, July.

Robert Thompson / Conopid fly (Myopa buccata) near Viscos, Pyrenees National Park, Hautes Pyrenees, France, June.

Nick Upton / Thick-headed fly / Wasp fly / Conopid fly (Myopa sp.) a parasite of bees, sunbasking on a leaf, Wiltshire garden, UK, April.