Mr. Spragg and Undine discuss the party at the Fairfords in Chapter 2, cracking jokes back and forth. Undine, just before the passage below, has explained that Mrs. Fairford is related to the Dagonets, a wealthy family. Mr. Spragg snaps back:
"What do they want to know you for, I wonder?" he jeered.
"Can't imagine—unless they think I'll introduce you!" she jeered back in the same key, her arms around his stooping shoulders, her shining hair against his cheek.
"Well—and are you going to? Have you accepted?" he took up her joke as she held him pinioned; while Mrs. Spragg, behind them, stirred in her seat with a little moan.
This sort of back-and-forth is typical of Undine and Mr. Spragg's relationship, as they make ample use of verbal irony. There is truth at the core of their jokes, though, and Undine speaks in "a tone between banter and vexation." Their jeering is, it seems, good-natured.
But the ironic moment (when Undine quips that the Dagonets must just be using her to get closer to Mr. Spragg) does point to an important feature of the Spragg parents throughout the novel. Mr. and Mrs. Spragg are as interested in Undine's social prospects as she is. This is due to familial affection, of course, but also due to personal interest. The Spragg parents want to ensure their connections in Fifth Avenue society, both socially and financially, so they live vicariously through Undine. While Undine and her father joke back and forth, they subtly evoke this tension in the family that carries throughout the novel.