Hoverfly

[peterbolson]

From meadow sweet. WL 8-9mm.
My first thought from the markings was Sericomya lappona but the aristae are not plumose and the scutellum is black not reddish. I'm sure someone will immediately recognize it
Peter

[Geoff F]

With those black stigma marks my first thoughts would be Dasysyrphus and quite possibly D. venustus. But there are a couple of other Dasysyrphus and I haven't run this one through the ID keys. So it is just an initial thought.

I have seen a few D. venustus this year; so they appear to be having a good season.

[peterbolson]

Hi Geoff
I thought Dasysyrphus had a yellow scutellum. This is definately black.

[peterbolson]

Geof
I've re-examined this with the microscope & when seen against a dark background with side lighting I can convince myself that the scutellum does look a very dark gold colour.
So you are probably right about it being Dasysyrphus, although it doesn't look a lot like a photo I have of a definate D.venustus.
Peter

[Geoff F]

I have now run this photo through the ID keys and I do wonder about Dasysyrphus hilaris which is almost identical to D. venustus. The dark '2 tone' orange or darker scuttellum is typical of this family.

What I (or a rear expert) requires is a look at the face. Is the facial knob yellow or darkish with a distinctive dark face stripe? D. hilaris has the plain yellow knob, but sometimes with a faint face stripe.

The frons dusting also appears like hilaris, covering at least half the width of the frons; venustus has narrow dusting just at the sides.

The hind tibia of hilaris has some darkening in the middle. I'm not sure about your specimen from that angle.

There are some other points about the length/width of the yellow bars but unless you see both species side by side it isn't completely obvious and I would claim lack of experience here.

So all in all, I suspect D. hilaris but I would like Roger Morris or another of the experts to give a second opinion.

ps. D. friuliensis does occur in your area but has distinctively 'waisted' yellow bands and black, or very dark, antennae.

[peterbolson]

Hello Geoff
Thanks very much for all your input. I took up your suggestion & had a look at the face ( see photo ) & unfortunately it clearly isn't D.hilaris. I think it must be D.venustus with slightly different markings from usual. I hope Roger will have a look at it.
Peter

[Geoff F]

Yes it clearly has the face markings of D. venustus but a rather large area of frons dusting and a faint dark mark on the hind tibia.

But D. venustus is a variable species and there is work afoot, by the hoverfly boffins, to further sub divide the species. So it is all going to get even more complicated.

It is almost getting to a stage like trying to sub divide people living in the same street by using different hair colours.

So D. venustus agg. may be a suitable category for this specimen.