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I photograped this fly in my garden at Rye Harbour in East Sussex, England on 18th May this year. The fly was frequenting ivy leaves in a sheltered hollow filled with a dead wood. The garden itself is relatively small and is bordered on one side by saltmarsh and ex-arable land with brackish pools on another, with the remainder being coastal shingle. Is it by any chance Thelaira solivaga?

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Sorry, seem to be having fun with my attachments!

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Unfortunately you have a classic intermediate specimen - with what looks like 3 anterodorsal bristles on the mid-tibia. Thelaira nigripes should have just 2 ad bristles and T.solivaga (& leucozona) have 4 ad bristles, which isn't very helpful in this case. So, were left with the colour of the abdomen, which isn't a very good character - but it would suggest T. solivaga on the basis that it is very orange. :) Would be nice to see the specimen though and have a closer look at it ;)

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Thanks for that. Unfortunately I don't have the specimen. though I do have a fly caught a few days earlier which keys out to T. solivaga using Bradshaw and definitely has four ad bristles on the mid-tibia. What is the status of T. leucozona? And any advice on separating it from the other two species?

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Thelaira leucozona is known from one museum specimen I think and was added to the UK list last year - I certainly haven't come across anything that keys to it and nobody I know has either! ;)

We're in the process of rewriting the RES book and the following is taken from our latest draft (no figure or page numbers yet). I think it should be OK but we haven't had a chance to test everything yet:

1. Tibia of the middle leg with only 2 long bristles on its antero-dorsal surface (fig.xxx) (possibly also a shorter bristle present nearer the tarsus), male abdomen with smaller orange markings - the intervening black stripe approximately half the maximum width of the abdomen, female tarsus with the second to last segment 1.5-2.0 times as long as broad (fig.xxx) .......... nigripes (F.)
- Tibia of the middle leg with 4 long bristles on its antero-dorsal surface (fig.xxx), male abdomen with large orange markings - the intervening black stripe only approximately one-third the maximum width of the abdomen, female tarsus with the second to last segment only 1.2-1.4 times as long as broad (fig.xxx) .......... 2
2. Outer vertical bristles weak, but about as long as 1/2 of inner vertical bristles. Calyptrae yellowish. Males: middle dorsal hairs of tergites 3 and 4 fine, as long as 1/7 - 1/5 of the marginal bristles; light side spots of the abdomen extended, clearly visible from above. Females: tergite 5 undusted .......... solivaga (Harris)
- Outer vertical bristles missing or hair-like. Calyptrae white (including the edge). Males: middle dorsal hairs of tergites 3 and 4 coarse, about as long as 1/4 of the marginal bristles; abdomen (seen from above) appears dark. Females: tergite 5 dusted at about the anterior 1/3 .......... leucozona Meig.

Key has been created by combining Belshaw (1993) with Tschorsnig & Herting (1994).

Chris R.

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Thanks chris, much appreciated

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This looks like solivaga to me.
Chris Bergstrom is in the process of redescribing Th. leucozona. It's very rare, but it is a bona fide species. With white calypters.

Theo Zeegers