What is the fly on the Pyramidal Orchid? It appears to be pollinating the flower -is that correct?
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Looks like a muscid or anthomyid fly to me but the photo isn't really clear enough to go further, I think. It is probably drinking nectar from the orchid but they are not particularly important as pollinators. If you can get closer, more detailed photos then an expert might be able to go further :)
I can't go any further on the fly, but it is not pollinating the orchid. Orchids don't have loose pollen like most flowers, but have it in two sticky masses (pollinia) that stick like horns to the head of a large insect or the proboscis of a bee or fly. You can see a pair of detached pollinia just below the fly, stuck to the orchid lip (not in the plan!). See also http://2.bp.blogspot.com/-Ckk2M8BkmEk/ThzHlgg9SPI/AAAAAAAABKY/2ft6X6o10h....
recording wildlife with The Recorder's Year on www.hbrg.org.uk/TRY.html.
Lat/Lng: 52.2202, 0.3328
OS grid ref: TL594605