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Stop ... I'm drooling all over my keyboard! :D No, no - go on - more!! ;)

Other than it looks like subfamily Tachininae (a bold-enough guess for me), I can't say more but I will pass these photos on to Jim in the hope that he might get closer :)

I visited Ecuador twice and went to places like Banos, Misahualli, Rio Topo etc but don't remember seeing such wonderful flies. What habits do they have? Did they come to any particular flowers or were they always on foliage?