low-humidity tolerant cattleya species?

[smweaver]

Does anyone who grows Cattleyas know of any species that are somewhat tolerant of low humidity levels in the winter? In the summer, I have no problem providing good humidity, as the plants all go outdoors and here in the Midwest the humidity is consistently oppressive (to humans at least), averaging between 80% and 90% (and often higher). But in the winter I can only manage to keep the humidity between 43% and (on a good day) 50%. Any suggestions for species (please, no hybrids--and no offense to everyone who loves the hybrids; they're often very nice but I just prefer the species) that could handle these lower winter levels will be very much appreciated. Thank you!

Steve