Ginny B's picture

Bibio marci (St Mark's Fly)

Observed: 23rd May 2012 By: Ginny B
S159 Neighbourhood Nature - course complete
Ginny B’s reputation in InvertebratesGinny B’s reputation in Invertebrates
Bibio marci (St Mark's Fly)

Black, between 10 and 15mm long. They seem to like sweet cicely (Myrrhis odorata) crawling over and between the flowers. When flying they dance up and down and dangle their long legs.

Species interactions

No interactions present.


Ginny B's picture

Thanks for the confirmation.

Thanks for the confirmation. Unfortunately I have trouble in getting a good close-up.

Comparing it to other people's photos here, I think that mine must be a female from the small size of the eyes. I have read that the male has much larger eyes.


ophrys's picture


Yes, the females are slightly larger than males and have very small eyes in comparison (males have holoptic eyes...meeting on the top of the head). This is probably marci, but really you need to be able to see the size of the spines on the front tibia and the wing venation, to be certain.


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