The mysterious (and very fertile) Lieutenant Vilix'pran is a character that has always intregued me. Going by what was said about him its a shame we never got to see the winged species.
That has just got me thinking; could he be Betelgeusian? Jake said about babysitting his young, needing to watch that their wings didn't get tangled. Going by the background notes on TMP the Betelgeusians had evolved from avians, and seeing as how we never saw one clearly there's no way to know if they still retain their wings or not.