I guess what I have heard called "tiger' lilies are very close to what you call "day" lilies.
One of our friends had a very tough little boy, whose mother thought to protect her tiger lilies by telling him "The tigers would get him if he pulled up any of the flowers". She came back a bit later, and found them all pulled up, and her son proudly told her "The damned tigers didn't get me!"
Here is a URL with pictures of some lilies. Not as good as I hoped for.

http://members3.clubphoto.com/michael262713/118833/guest_icons.phtml