Anybody recognise this sawfly?

Geoff F · #1 (**permalink**) 30-04-2009, 02:29 PM

During a sunny gap between the showers yesterday, I went for a walk along the coast path, S. Devon, but ended up in an interesting corner of a field.

Think this is probably a sawfly but, if so, I can't get a 100% ID. I thought Rhogogaster sp. based on the wide head and mostly black topped abdomen. Maybe R. picta/genistae but I can't get the leg and thorax colouration to match.

Unfortunately not enough detail in those images to follow the keys to an ID so I wondered if anybody might be able to just say 'I recognise that fly'.

Laurence Clemons · #2 (**permalink**) 30-04-2009, 02:33 PM

It is one of the black and yellow Tenthredo species. The species names have changed a lot recently so I will need to get back to you on this. They're out early this year.

Geoff F · #3 (**permalink**) 30-04-2009, 07:49 PM

Thanks, Tenthredo and Cephus (on a yellow flower in a grassfield) were both on my list but I just couldn't narrow things down any closer with that poor photo. Didn't have a 'proper' macro lens with me.

Incidentally, I also saw, and took a very poor photo, of what looks like a Picture Winged Fly. But it wouldn't stay still long enough to get a decent sharp image.

JRsbugs · #4 (**permalink**) 30-04-2009, 10:05 PM

Tenthredo arcuata

Janet

oxycera · #5 (**permalink**) 01-05-2009, 07:43 AM

I wouldn't be happy trying to id one of the 'arcuata group' from a photograph

Laurence Clemons · #6 (**permalink**) 01-05-2009, 09:56 AM

The 'arcuata' group are best identified by looking at the teeth on the female's saw. The usual black and yellow species found at this time of year is Tenthredo temula (also known as celtica) but this has long, thin black antennae.

JRsbugs · #7 (**permalink**) 01-05-2009, 01:40 PM

If you check out the pics of Tenthredo arcuata on Hymis I think you will find this is spot on.

Fotogalerie - Hymenoptera Information System (HymIS)

Janet

oxycera · #8 (**permalink**) 01-05-2009, 05:09 PM

Can't see how it can be 'spot-on' when it's impossible to see the critical features!

JRsbugs · #9 (**permalink**) 01-05-2009, 06:13 PM

Quote:

Originally Posted by oxycera

Can't see how it can be 'spot-on' when it's impossible to see the critical features!

Well if we're getting that technical it is impossible, such as a need to view the teeth on the female's saw as referred to by Laurence. But I think you would agree that the pattern does match, and for the purpose of a simple as-near-as-can-be-got ID I imagine Geoff might be happy enough with that, not having a specimen etc. to confirm, but he could if he wished add a little note that it is not a certain ID. Then again he could ignore it all together!

oxycera · #10 (**permalink**) 01-05-2009, 08:08 PM

Had I realised that only an approximate id was being proffered, then of course I wouldn't have contributed to this thread, as T.arcuata is a strong candidate and as good as anyone could have suggested.