Stephen Falk has produced a Flickr collection of British Snail-killing Flies. Hope you find it useful

A family of small to medium-sized acalypterate flies (British species 2-11 mm long) with 72 British species (2016). Many species have patterned wings and the antennae are often elongate, porrect and arising from a projecting frons (notably members of the tribe Tetanocerini) which creates a distinctive ‘alert’ appearance. Sciomyzids often walk in a slow and deliberate fashion which can make them stand out from other acalypterate flies when checking the contents of a net. They are particularly numerous and diverse in lush wetlands.

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