Final answer:
Mr. Collins' letter to Mr. Bennet, discussing Lydia's elopement with Mr. Wickham, is not quoted in the provided excerpts, but it contains his views on the impropriety and repercussions of her actions for the Bennet family.
Step-by-step explanation:
The information included in Mr. Collins' letter to Mr. Bennet regarding Lydia's behavior is not directly provided in the excerpts given. However, it is known from Jane Austen's Pride and Prejudice that Mr. Collins writes a letter expressing his concern and condemnation for Lydia's elopement with Mr. Wickham, which is seen as a disgraceful behavior that could tarnish the reputation of the entire Bennet family. Mr. Collins advises Mr. Bennet on the impropriety of Lydia's actions and often includes moral and social advice in his correspondence.