About St Mark's Fly
A small black fly that swarms in May. Males have large heads with huge eyes that almost meet on top.
Did You Know?
Often confused with the larger Bibio marci but emerges slightly later and has entirely dark legs.
Distribution
Where St Mark's Fly can be found
Seasonal Activity
Peak activity
Moderate
Low / dormant
Cite This Page
APA:
Orbitrock. (2026). St Mark's Fly (Bibio johannis). Retrieved from https://orbitrock.com/insect/st-marks-fly
MLA:
"St Mark's Fly." Orbitrock, https://orbitrock.com/insect/st-marks-fly.