Whoever finds a missing dog will earn a reward, according to police.

“Bing,” a Boston Terrier/Chihuahua mix, was last seen Saturday at Central and Speen streets in Natick, according to a tweet on the Wellesley Police Department’s Twitter page, but police are asking area residents to be on the lookout.

The tweet, which has a photo of “Bing” and the words “Lost Dog” and “Reward,” says “Bing” is 16 pounds with a brindle coat and in need of medication, the tweet says.

Police are telling residents to e-mail BingLostDog@gmail.com or call 919-452-8288 if the dog is spotted.