Abigail deflects blame onto Tituba, Reverend Parris's Barbadian slave, near the end of Act One. When Hale asks her what she is hiding and if she's sold her soul to the devil, she points at Tituba, shouting, "She made me do it! She made Betty do it!" Abigail proceeds to lie and claim that Tituba forced her to drink blood; that Tituba sends her spirit onto her at church and forces her to laugh during prayer; that Tituba compels her to stand naked in the doorway. Abigail clearly gets nervous that she is going to be accused of some pretty big sins/crimes, so she blames one person who has even less power than she does. This is located on pages 43-44 (in my edition).
Abigail deflects blame onto Mary Warren in Act Three. She obviously fears that suspicion will alight on her as a result of Mary's new testimony. She begins to point and act afraid, speaking to a "yellow bird" that "want[s] to tear [her] face." She calls the bird "Mary" and speaks as though it could understand and respond; Abigail says to it that she "cannot stop [her] mouth; it's God's work" she is doing in the court. The ruse works, and Mary eventually turns on John Proctor, accusing him of witchcraft and declaring that she, herself, loves and wants to return to God. This begins on pages 114-115.