In Much Ado About Nothing, Shakespeare uses many allusions in Beatrice's language as one means to characterize Beatrice as an intelligent, socially rebellious wit.
Allusions can be seen in her first speeches found in act 1, scene 1. She makes an allusion to Cupid in order to insult Senior Benedick. More specifically, she relates to a messenger a made-up story about Benedick challenging Cupid to an archery contest, but Cupid did not take him seriously. As a result, her uncle's fool went to the challenge instead of Cupid but only challenged Benedick as a first-level player because Benidick's skills are only at the first level. She then asks the messenger how many people Benedick has "killed and eaten" at the wars, "for, indeed [she] promised to eat all of his killing" (I.i.32-37). The purpose of all of Beatrice's silliness, including the allusion to Cupid, is to poke fun of Benedick by saying he is useless in both love and war (eNotes, "e-text Act 1, scene 1").
Another example of an allusion can be seen in act 2, scene 1. When rebuked for being such a shrew, she makes an allusion to a myth saying that old maids were believed to "lead apes into hell," saying that she would rather lead apes into hell than marry a man either with or without a beard, as we see when she says, "Therefore I will even take sixpence in earnest of the bear-ward, and lead his apes into hell" (Shakespeare-Navigators, note 41). The term "bear-ward" refers to a bear-trainer, which also sometimes trained apes as well as bears; hence, Beatrice is saying she would rather be paid by a bear-trainer to lead his apes into hell rather than marry a man (eNotes, "e-text, Act 2, scene 1").