zhouqi's picture


Observed: 14th May 2013 By: zhouqi

I have seen these last week, in more than one places in Cambridge. Near edge of path/railway/hedge/grass, flying in small swamps, pitch black, about 2cm long. Looks nasty but not attacking me. They are not ants.
Sorry not good photos.

Species interactions

No interactions present.

Species with which St Marks Fly (Bibio marci) interacts


Mydaea's picture

Probably St Mark's fly Bibio

Probably St Mark's fly Bibio marci. Nearer 1cm than 2cm.

jeremyr's picture


these all came out on saturday here and scared the life out of me. Certainly a good 18mm. I'm not sure if that means it's a different Bibio. The 1cm flies I found were gifts between mating Empids. I collected both so they might look interesting side by side but I'm not sure if they're the same species

latest pics and diptera videos

Mydaea's picture

No - it is my error. I was

No - it is my error. I was thinking wing-length, not body-length

zhouqi's picture


I read on the web of St Marks fly, I can confirm it mostly like was. It was its flying style that caught my eyes.