Best time to see: late Apr to end May
Key facts
A large black fly, appearing in large numbers around St Mark's day, April 25th
Widespread and common in rough grassland, hedgerows and pond margins
Believed to be important pollinators of fruit trees
Recognition
Large bulbous eyes distinguish the males from the females
Fly sluggishly with legs dangling
Lifecycle
Larvae feed on the roots of grasses and decaying plant material, often in compost heaps
Emerge around the end of April, climbing up plant stems and bushes looking for mates
© Tony Gunton