The Society for the study of flies (Diptera)

So many male Syrphus that I find key out to S torvus, due to the hairy eyes, that I began to get a bit suspicious and checked a wing for microtrichia today.  Sure enough, the second basal cell was mostly bare of microtrichia, ruling out S torvus.

The other Syrphus species are said to be bare-eyed in Stubbs & Falk and in all other sources that I can locate, except for an obscure comment on http://www.wildaboutbritain.co.uk/forum … orvus.html where it is said "The only problem is S.ribesii and S.vitripennis also have scattered hairs on the eyes although less than S.torvus."

Is this correct, or are they totally bare-eyed?  I must say the specimen I'm currently looking at does not have the hairs quite as dense as usual, but they are close enough to fit the description "eyes densely hairy" rather than "eyes bare".

If the other species do have hairy eyes, it will still be easy to separate male vitripennis/rectus from torvus (only to have to discard the record due to not knowing whether it's vitripennis or rectus), but is there any way to separate male ribesii from torvus?

Many thanks

Carl