The Blandford fly (Simulium posticatum) is a species of black fly, a biting insect found in Europe, Turkey and western Siberia. It spends its larval stage in the weedbeds of slow flowing rivers and when the fly emerges, the female seeks a blood meal before mating. It usually bites the lower legs causing pain, itching and swelling. Scratching the irritated areas can lead to breaks in the skin, after which secondary infection may set in.