Fantastic! Your making me think I need to take a trip to Mexico!
The ID is a bit of a best guess. There are a few similar species, all off whic seem to have been moved to the genus Coilostylis. Apparently Epidendrum nocturnum is the type sp. of Epidendrum, so would be tough to shift but when you compare the flowers, it's hard to see how they seperated the others. Anyway, there's Coilostylis ciliaris, which this clearly isn't: http://en.wikipedia.org/wiki/Coilostylis_ciliaris
Coilostylis parkinsonia, hmm possible but mid lobe of lip I looked at on most pics seems to be a fair bit shorter than your spot: http://www.orchidspecies.com/coilparkinsoniana.htm
and Coilostylis oerstedtii, which I think is the most likely other option from E.nocturnum: http://www.orchidspecies.com/coiloerstedii.htmE.oerstedtii
Would be good to compare this with a proper Mexican Orchid Flora book, but don't have access to one at the moment.
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