Rod Williams / Snail-killing fly (Tetanocera Sp) Sutcliffe Park Nature Reserve, Eltham, London, England, UK. August.

Rod Williams / Black scavenger fly (Sepsis punctum) feeding on minute food particles off bramble leaf, Brockley Cemetery, Lewisham, London, England, UK. October.

Nick Upton / Dryomyzid fly (Dryomyza anilis) on leaf in woodland, Gloucestershire, UK, October.

Nick Upton / Dryomyzid flies (Dryomyza anilis) preparing to mate on a toadstool in woodland, Gloucestershire, UK, October.

Rod Williams / Snail-eating fly (Trypetoptera punctulatus) Brockley Cemetery, Lewisham, London, UK. May

Nick Upton / Marsh fly / Snail-killing fly (Dichetophora obliterata) standing on a Bramble leaf, Wiltshire hedgerow, UK, September.

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

Kim Taylor / Snail-killing fly (Coremacera marginata) pair mating. Surrey, England, September.

Kim Taylor / Snail-killing fly (Coremacera marginata) pair mating, viewed from above. Surrey, England, September.

Terry Whittaker / Arctic fox (Vulpes lagopus) blue colour morph in summer coat, feeding on Kelp fly (Coelopa sp.) larvae along the coast, Hornvik, Hornstrandir, Westfjords, Iceland. July.

Roman Willi / Marsh flies (Tetanocera sp.) mating pair, Lucerne, Switzerland. May.

Andy Sands / Stripe-backed snailkiller fly (Limnia unguicornis), female, in typical head down pose on grass. Buckinghamshire, England, UK. May. Focus Stacked.

Andy Sands / Stripe-backed snailkiller fly (Limnia unguicornis), male, in typical head down pose, with rain drops on grass. Buckinghamshire, England, UK. May. Focus Stacked.

Andy Sands / Stripe-backed snailkiller fly (Limnia unguicornis), male, climbing back up grass after rainy shower. Buckinghamshire, England, UK. May. Focus Stacked.

Andy Sands / Snail-killing fly (Pherbellia cinerella) in typical head down pose on grass stem with rain drops. Buckinghamshire, England, UK. May. Focus Stacked.

Andy Sands / Blue long-horned snailkiller fly (Sepedon sphegea), male, in typical head down pose on sedge stem. Buckinghamshire, England, UK. May. Focus Stacked.

Andy Sands / Blue long-horned snailkiller fly (Sepedon sphegea), male, in typical head down pose on sedge stem. Buckinghamshire, England, UK. May. Focus Stacked.

Doug Wechsler / Marsh fly (Sciomyzidae sp.) on log, La Selva Biological Station, Costa Rica.

Doug Wechsler / Marsh fly (Limnia sp.) on leaf, Philadelphia, Pennsylvania, USA. June.

Andy Sands / Fly (Dryomyza anilis) sitting on Saprotrophic fungus (Mycena sp). Buckinghamshire, England, UK. October. Focus stacked image.

Andy Sands / Snail Killing Fly (Sciomyzidae sp.) perched on reed stem above pond, Hertfordshire, England, UK, August

Andy Sands / Snail killing fly (Sciomyzidae sp.) perched on reed stem above pond, East Sussex, England, UK, July. Focus Stacked