A mosquito offers to help an old man to discover the tastiest piece of meat, and free him from a terrible snake that wants to eat him. In compensation the old man provides the insect with iron dentures so that no victim can escape, but the smart insect will use them to satisfy its excessive voracity In a humoristic key, this traditional Chinese tale, of an aetiological nature, reveals why the mosquito, instead of speaking, emits a buzzing sound as if it were a war cry and lets us know why snakes eat mice and swallows are mans friends.