Related Clues:

• Queen's attendant
• Monotonous tone
• Bee in a hive
• Remote-controlled craft
• Sing sans melody
• Plane sans pilot
• Go on (and on, and on ...)
• Queen's mate
• Unchanging intonation
• Ambient sound
• Long hum
• Talk in a monotonous voice
• Go on monotonously
• Remote-controlled plane
• Bee sound