Mystery solved over plague of flies near Horsham

St Mark's fly. Photo: Buglife.org.uk SUS-190430-155243001
St Mark's fly. Photo: Buglife.org.uk SUS-190430-155243001

Mystery swarms of ‘horrible black flies’ that have been plaguing a village near Horsham have finally been identified.

People in Billingshurst say that the gardens of their homes suddenly became infested by the insects last week.

Many took to social media to complain about the menace.

But now local author Pauline Emsley has revealed that the bugs are insects known as St Mark’s flies. “They’re absolutely harmless,” she said.

St Mark’s flies - Bibio marci - are also known as hawthorn flies. The insects emerge every year around St Mark’s Day - April 25. They are found around woodland edges, hedges, rough grassland and wetlands and can be seen throughout the UK in spring.

There were reports last week of the flies being spotted all over Billingshurst, particularly the Penfold Grange area of the village, in Morris Drive and Parbroom.

Meanwhile, Pauline, who has studied botany, zoology and biology, said she herself had spotted one of the flies when she was out with an art group in Rogate last week. “I knew straight away what it was. They all come out at the same time.”

She said many people didn’t like the look of the little black flies. “The modern human doesn’t like creepy crawlies, but they are harmless.”

Pauline, who lives at Coneyhurst, is the author of several children’s books, including Rag Doll Lost and The Tear Dragon.