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#1 2014-06-05 23:35:22

Gateside
DF Members
Name: Nigel Gilligan
From: Cumbria
Registered: 2011-08-26
Posts: 1045

Empididae (maybe), v small, unusual features

I have decided it's probably an Empididae, on the basis of the piercing mouthpart, the shape of the thorax and general appearance. However it's very small, about 4 mm long. It would appear to be a female, with a distended abdomen and pointed tip.
There is no chance of using a key on it - I've tried and given up!

What I have decided is striking about this (hopefully) are:
a) the more or less all yellow legs, except for the black bands on the tarsi (a bit like some Athalia genus sawflies)
b) the large black tibial spurs on the mid leg only
c)  the thorax is a sombre golden colour, with no sign of dark lines.
d) it looks like the 1st antennal segment is yellow, the rest is black


I would be grateful for any comments, including a recommendation to give up!

Nigel


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#2 2014-06-06 00:18:11

jeremyr
DF Members
Name: Jeremy Richardson
From: Tottenham
Registered: 2012-12-31
Posts: 224

Re: Empididae (maybe), v small, unusual features

Platypalpus, so Hybotidae. You can tell by the swollen middle femur, used for gripping prey. Someone might suggest a species - there is a key for them if you get specimens

Jeremy

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#3 2014-06-06 09:53:14

Gateside
DF Members
Name: Nigel Gilligan
From: Cumbria
Registered: 2011-08-26
Posts: 1045

Re: Empididae (maybe), v small, unusual features

Thanks very much, Jeremy.  That is impressive. I did notice the swollen femurs, but then quite a few species have that. I see that some threads about these refer to the problem of having a female, so cannot ID. On the other hand, if I have (unknowingly) seen a playpalpus before, I've not seen one like this.

Nigel

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#4 2014-06-06 13:10:09

afbainbridge
DF Members
Name: Anthony Bainbridge
From: Codford, Wiltshire
Registered: 2008-10-25
Posts: 39

Re: Empididae (maybe), v small, unusual features

Certainly Platypalpus, and I'd go for P. pallidiventris from what one can see on the photo - but an i/d from a picture is always risky.   The strongly annulated tarsi are a good pointer, together with the yellow basal antennal segment, the yellow biserial acrostichals and dorsocentrals and the long thin terminal papillae.  The abdomen is indeed extended and she's is (was?) gravid.

Anthony Bainbridge

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#5 2014-06-06 18:46:07

pbrighto
DF Members
Name: Phil Brighton
From: Warrington
Registered: 2011-10-21
Posts: 363

Re: Empididae (maybe), v small, unusual features

There is a key by Adrian Plant in DF Bulletin No 73 (Spring 2012).

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#6 2014-06-07 10:02:23

Gateside
DF Members
Name: Nigel Gilligan
From: Cumbria
Registered: 2011-08-26
Posts: 1045

Re: Empididae (maybe), v small, unusual features

Thanks very much for your helpful comments. I have found my bulletin (amazingly), and it's a struggle without a specimen. Even placing the insect into the initial groups is doubtful.  The suggestion of P. pallidventris is interesting, but having checked all my images, I see no suggestion of dark satae on T1 & T3, though the ones on T2 are very large and obvious.

I will try a bit more, but strongly suspect I won't be able to ID. However, I have got much further than I could have hoped for.
Thank you!

Nigel

ADDITIONAL. After checking again, I decided that it fitted best (though I can't be pedantically certain) into either the Key G, or Key I. I quickly hit the buffers with key I.

Going through key G, I don't think vein M is bowed, and it has the face silvery-grey (prob), abdomen distinctly dusted on the lateral margins, T2 with apical spur sharply pointed (and T1, T3 not), tarsi strongly annulated, which makes it P. flavicornis.

However, I cannot find any images of this species, just a few random ones from the rest of the genus. I wouldn't like to stick my neck out any further without seeing something that purports to be this species.
Can anyone still advise?

Nigel

Last edited by Gateside (2014-06-07 16:33:51)

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