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July 08, 2006.
Size 7mm.
It would take off, cruise for a while and return to sit on the bark (of a pine tree nearby, too). Exposed its long proboscis.

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One more view.

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As far as I know, it is Aphria sp., Tachinidae.
Nikita

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OK thanks (I nicked the family again!)

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I think it looks more like Prosena siberita - was the arista plumose?

(Aphria is smaller and darker and the proboscis isn't as long - see http://tachinidae...rcno=13001)

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In this case Chris
http://www.rosfoto.ru/shop/photo/42525/ and
http://www.rosfoto.ru/shop/photo/42524/
are misID as Aphria?

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Hi Nikita, in my opinion those are both Prosena siberita again - that's certainly what I would call them in England - if the arista is plumose Just look at those legs - they are long and thin, like other dexiines (Thelaira etc)

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In my key Aphria 6-8mm, Prosena - 10-12; but Aphria black legs, Prosena - yellow with black tarsi.
More probable that Black gave us smaller size, as legs colour is clearly visible.

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Well, don't forget that the size they give is the average size for normal specimens. There are always small ones because the development of a parasitoid is dependent on the development of its host - sick, weak host = small parasitoid. I have a tiny Tachina fera here - about 8mm or less.

The difficult thing with these photos is that the antennae and arista are not clear. If it was clearly plumose then the keying would be easy and it would go very fast to Prosena I think

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At least Chris, there are only two genus of Tachinidae with such proboscis, I hope?

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Well, Siphona have a long proboscis but theirs is hinged

I caught Rhamphina pedemontana in the Pyrennes one year (see photo) but this species carries the proboscis under the body I think - and it is mainly southern in distribution. It's a superb fly - the same size as a large Eurithia sp.

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Hi guys I almost missed the case again.
First, I underestimated the size just as Nikita suggested (2 collected specimens are 9mm).
Second, aristae are hairy.
Third, legs are reddish (with tarsi rather dark).
I'll upload more images soon.

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Here's a lateral view.

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A week has passed, and I decided to check this tree. And voila, these nice flies were still swarming there. I also spotted more flies, roughlu the same location eithin the range of 1km, strictly on P. tremula, and just single flies. Those were much calmer, and I easily picked one with my hand.

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Lovely photos, as usual. I saw something similar to Prosena here in England 2 days ago but I didn't get my net on it fast enough - here they much be much faster!

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...or englishmen are much slower. Naah, can't be.

I have never seen this fly in my life. Too fast for me to see - maybe faster than local lightspeed?

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Actually, I don't think I have seen one flying (except maybe that one yesterday - and now we'll never know) ... all the ones in my collection were nice and slow ... and pickled in alcohol from my Malaise trap!

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I remember seeing these and catching them off tree trunks (with a little bit of difficulty) - but that was over thirty years ago!!!
Maybe Irish Prosena are a bit slower?

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Today just in a couple of minutes I collected four more flies on the same aspen using only plastic film boxes. My opinion still is that these flies are not slow but lacking some wit unlike Muscidae which hardly would let one catch them with one's (almost) bare hands.
They were absent at 11a.m. but were alreadt there at 15.30 when I returned to the tree to check again.
I also saw single sitting flies on old poplars, all covered with yellow lichens (Xanthoria parietina I believe), along the railroad.

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Yesterday I've found out that P. siberita occurs as late as late August and also visits flowers (Solidago canadensis, widely introduced here and rich source of flies, especially Syrphidae, Tachinidae, and Conopidae - highly recommended ).