Thread subject: Diptera.info :: Eristalis with 'deep' head?

Posted by Jason G on 01-11-2010 00:48
#1

Evening all,

I collected this fly in May or so, in London. Now, I've tried keying it out using van Veen's key (I'll get S&F once I have a few more RES keys while they're in stock), and got to coup. 9 - http://web.archive.org/web/20070423163827/http://home.hccnet.nl/mp.van.veen/KEYS/Eristalis/eristkey.html#item9

Now, under the microscope the tarsi are dark brown with few pale hairs except for the basal half of the first tarsus which is pale. I think this steers it away from pertinax, and away from arbustorum since the top-half of tibia2 is pale.

Now, the head in profile appears quite deep (to me!), but jugorum isn't on the British list. If it isn't this one, then following it on you come to lineata - except there are no black hairs at all on T3-4 - distal or otherwise.

So... any thoughts on the basis of these images? I don't know how accurate the key is compared to Mark's original work and I will try with the UK key when I get it - but can get additional photographs if they may help.

Thanks for reading.

Take care,

Jason

Edited by Jason G on 01-11-2010 02:23

Posted by Jason G on 01-11-2010 00:49
#2

Lateral... note the apparently dark tarsi and the way the lower part of the head is quite 'inflamed' - it's deeper than my others - E. tenax, arbustorum and intricarius.

Edited by Jason G on 01-11-2010 00:54

Posted by Jason G on 01-11-2010 00:51
#3

Head...

I suspect it IS pertinax, it just looks quite unusual in my limited experience.

Edited by Jason G on 01-11-2010 01:02

Posted by Auratus on 01-11-2010 08:04
#4

It seems the pterostigma is very small. Also an important feature ;)

Posted by Jason G on 01-11-2010 16:32
#5

New views taken today - the Pterostigma...

Posted by Jason G on 01-11-2010 16:33
#6

Side-view of the head...

Posted by Jason G on 01-11-2010 16:34
#7

...and the front tarsi - brownish, not yellow in my opinion.

Posted by Quaedfliegh on 01-11-2010 17:29
#8

I think Jan is referring to a species with small pterostigma; E. nemorum. With Dutch key that is the conclusion.

Posted by Jason G on 01-11-2010 19:37
#9

Sorry Jan! I didn't see your reply. Apologies! That looks great - isn't that now Eristalis interrupta?

Thanks for highlighting that for me + providing the name, Reinoud!

I'll now back-track through the couplets, and find where I went wrong.

Thanks again! :)

Posted by Andre on 03-11-2010 20:48
#10

'Deep head'....? LOL :P