Thread subject: Diptera.info :: Tachinidae - Thelaira?

Posted by tim worfolk on 18-06-2009 16:37
#1

To my untrained eye this looks similar to a Thelaira I posted a few weeks ago, but is it?. Apologies for the poor quality of photo - I couldn't get any closer.

18/6/2009, Devon, England

Thanks

Tim

Posted by tim worfolk on 18-06-2009 16:38
#2

slightly different angle.

Tim

Posted by ChrisR on 18-06-2009 18:23
#3

Yes, Thelaira alright ... and I'll stick my neck out and say T.nigripes, due to the relatively few ad bristles on t2 :)

Posted by tim worfolk on 19-06-2009 08:28
#4

Thanks Chris, T.nigripes was my guess, but it's hard to be sure the bristles aren't there, or are broken, or are just hidden by the angle of view.

Looking back to my previous post of Thelaira solivaga, Theo mentioned a 'distinct ve', this puzzled me then and I haven't been able to find out what he meant - unless it was ventral?

Thanks

Tim

Posted by ChrisR on 19-06-2009 09:30
#5

ve and vi are terms used in the European keys ... I always remember them as "vertical exterior" and "vertical interior". Basically the inner and outer vertical bristles - the tall vertical bristles between the eyes and behind the ocellar triangle, in front of the post ocular hairs. :)

Thelaira can be a bit of a tricky genus because individuals are quite variable but the ve provides another handy feature that can confirm an ID.

Edited by ChrisR on 19-06-2009 09:34

Posted by tim worfolk on 19-06-2009 11:07
#6

Thanks Chris.

I went back to my original Thelaira to see if I could understand what you mean. I've cropped and enlarged and labelled ve and vi; I hope this is correct.

Thelaira solivaga photographed 20/5/2009.

Posted by tim worfolk on 19-06-2009 11:10
#7

Then I did the same with my Thelaira of yesterday - poorer quality as a much greater enlargement but I think I can see enough.

I think I can make out a ve, or am I pushing it too far?

Thelaira sp. 18/6/2009

Posted by ChrisR on 19-06-2009 11:38
#8

Hmm, not entirely sure - we need Theo's vast experience - or a specimen, But I was largely going on the apparent shortage of ad bristles on the mid tibia (I can see 1 so I assumed maybe one was broken off) but if it has been really battered about then perhaps it had more ... difficult one - it's sometimes hard to be sure with worn specimens. The European key says that nigripes has a ve that is "missing or hairlike" so it's possible that yours qualifies as just "hairlike" because it does look a bit small :)

I am not 100% convinced but it's a guess based on what I can see :)

Posted by tim worfolk on 19-06-2009 12:02
#9

Well if you're not 100%, I most definitely don't know. As you say, Theo's opinion would be very welcome. A specimen is not likely, I carry enough gear already without adding a net and tubes (maybe I should get an assistant?). I suppose I'll just have to try for better photos...

BTW the European key I presume is the one I can download from Tachinidae.org. I'll get a copy and email you for a password. Sounds like it would useful even for a photographer.

Thanks again for all your help.

Tim