Possible Clues:

• The catch in this is sung
• A cowboy's working rope
• That noose has a song in it
• There may be a catch in it and there is a song in it
• Rope for the cowboy
• It goes around around a roundup
• Given enough rope, there'd be a song in it
• The catch is that there's a song in it
• That lass? O, she's out to catch one
• There's a song in it - and maybe a catch in it, too