Interestingly, this is Oncidopsis (syn. Vuylstekeara) Cambria x Oncostele (syn. Odontioda) Hambühren, which contains Rhynchostele rossii. The large white lip might be a trait inherited from Rst. Grown by Helmut Sang
'Orchid-Mimicry': Much too good an attempt at that. To be an Orchid, and as if that was not beautiful enough in itself, and then try and mimic a butterfly! Flowers of Lepanthes mariposa mimicking a butterfly - Flickr - Photo Sharing!