Chrystogaster virescens ?

[peterbolson]

On hogweed along woodland ride behind my house. WL 7mm.
Top of thorax and scutellum greenish & virtually hairless. Pleura glossy above front coxa. Antennae orange.
According to S&F should be found on bogs and wet acid pastures whereas this is in a limestone gorge so I want to be sure of the ID. S&F does say that adults can congregate at flowers some distance away.
Thanks
Peter

[Geoff F]

But what about it's face and is it male or female?

Stubbs also states that C. cemiteriorum is variable and can be confused with C. virescens. Females normally have less darkening on the wings but males are separated by the flatter face of C. cemiteriorum.

It's another tricky species isn't it.

[peterbolson]

Hi Geoff - I like to keep your mind working
Here's a better view of the facial profile, but as it's a female this may not help. Stubbs says the unique character of C.cemiteriorum is the grey dusting above the front coxa & I can see none of that with the microscope. The wings are pretty dark.

Peter

[Geoff F]

Being female is a great help as that weeds out a few possible alternatives.

Much of the following, as frequently occurs with this family, is based on personal thoughts though.

But if you go back to the key on page 131 and section 5 (where females start) 'Wings strongly blackish. Thorasic dorsum with purple reflections'.

Now I would suggest that you specimen has a distinct purplish tinge. It is the first thing which I noticed about it.

So that is making me consider C. solstitialis as a possible answer. Dark wings and bright red eyes. But I'm not sure about antennae colours. However, the face width should settle this one way or another. Relatively narrow for C. solstitialis and quite wide for C. virescens.

Any help, or just adding to the confusion?

[peterbolson]

Geoff - your help is much appreciated. I always learn alot from these didscussions.
Here's a shot of the face. I would say it was wide, but what do you think ?
Peter

[Geoff F]

That certainly appears to be wide spacing. The Stubbs diagram gives the spacing between the base of the antennae and the eye edge as approx the same as the width of the antennae base for C. virescens. Which is similar to your specimen.

C. solstitialis is less.

As it is female, we should be able to rule out C. cemiteriorum on the basis of dark wings in your specimen; and C. solstitialis based on the face width.

So it would appear to be C. virescens with rather dark wings and a poor sense of direction!

[Jason Green]

Evening Peter,

Nice shots - I can't add anything helpful to this this, but just wanted to say there's some great detail there.

Take care,

Jason