Yellow fly identification

[GreenGardener]

We've seen three of these yellow flies on the red stems of a climbing rose yesterday, does anyone know what they are? Apologies for the poor quality of the photograph!

[JRsbugs]

It's a Sawfly, and will be laying it's eggs in the new tender stems of your rose. I took pics of one last year doing it, possibly an Athalia sp. in the Family Tenthredinidae.

I don't worry about them, they don't seem to be spoiling my roses and many get eaten by other predators.

Janet

[oxycera]

I know its a poor photo, but perhaps its more likely to be Arge pagana?

[Jason Green]

I agree, A. pagana.

[JRsbugs]

Originally Posted by oxycera

I know its a poor photo, but perhaps its more likely to be Arge pagana?

I believe Arge pagana has all black legs? I can see some yellow on the hind femur.

Fotogalerie - Hymenoptera Information System (HymIS)

[oxycera]

Originally Posted by JRsbugs

I believe Arge pagana has all black legs? I can see some yellow on the hind femur.

Fotogalerie - Hymenoptera Information System (HymIS)

not according to Quinlan and Gauld, or, indeed, specimens in my collection

[JRsbugs]

Originally Posted by oxycera

not according to Quinlan and Gauld, or, indeed, specimens in my collection

It states on gardensafari legs are "usually" entirely black, so I gather there is the occasional variation? All the pics I'm seeing they are black.

The penny has just dropped, on delta-intkey there is A. pagana ssp. stephensii which has yellow hind femora.

[oxycera]

perhaps you're looking at continental sites where the dark form is prevalent?

[JRsbugs]

Originally Posted by oxycera

perhaps you're looking at continental sites where the dark form is prevalent?

Well, not having the benefit of a book to refer to, and being mindful that these are always tricky with so many being so similar, on top of that I haven't had one of these for two years to notice, but I have had so many new ones this year I tend to go with what is currently in my mind sometimes, a human failure I guess but as I wanted to get outside that also made my decision making a little lax. I'm sure you will understand all these reasons. You did ask!

[oxycera]

...?? did I? you thought it might be an Athalia and I wondered if it might be Arge. It's really no big deal