Possible Clues:

• Be seated, Richard, for a CID
• Acid of oranges and lemons
• Like the acid in limes
• Sounds as if one might sit with Richard of Orange
• Like ugli fruit
• The acid way to tell Richard to be seated
• Caught by one incomplete scam, like a lemon
• Lemonlike
• Derived from eg, lemon
• Take a seat, Richard; this is a CID matter