moongirl01's picture

Robber fly or something else?

Observed: 18th April 2011 By: moongirl01moongirl01’s reputation in Invertebratesmoongirl01’s reputation in Invertebratesmoongirl01’s reputation in Invertebratesmoongirl01’s reputation in Invertebrates
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This insect was resting on some vegetation at the side of my pond. Is it a robber fly?

Species interactions

No interactions present.

Species with which St Marks Fly (Bibio marci) interacts


Fenwickfield's picture


I get swarms of these were I live to the extent that it is best to stay indoors some days.


ophrys's picture


Where I am, I have only seen a couple of marci, so far, whereas other species have been very common indeed. They are worth keying out, perhaps, unless obviously large and black.


My Flickr photos...

moongirl01's picture

Thanks for identifying this.

Thanks for identifying this. I must have overlooked it in my insect book (the diagram in there shows an individual with a much smaller head). Upon further reading, I understand that male St Mark's Flies have larger heads so I assume that's what I saw.

Fenwickfield - It's interesting to read that you get swarms of these insects where you live. I think it's the first one I've seen!

ophrys - Thanks for your comments too.

Fenwickfield's picture

Will put them on

I will get some pictures taken and put male and female on.


moongirl01's picture

Thanks! I look forward to

Thanks! I look forward to seeing them.