Meaning of "It isn't a bit hotter here than in Mrs. Van Osburgh's conservatory—and some of the women are not a bit uglier"

Question

On page 2 in Edith Wharton's The House of Mirth, Lily Bart has missed the three-fifteen train to Rhinebeck when she meets Mr Seldon:

"What luck!" she repeated. "How nice of you to come to my rescue!"

He responded joyfully that to do so was his mission in life, and asked what form the rescue was to take.

"Oh, almost any—even to sitting on a bench and talking to me. One sits out a cotillion—why not sit out a train? It isn't a bit hotter here than in Mrs. Van Osburgh's conservatory—and some of the women are not a bit uglier."

What does Lily mean by the sentence in bold? The way it is phrased suggests that it is a joke, but if so, how does the joke work?

Answer 1

It is indeed a joke. She's saying that at a cotillion (in case, you're not familiar, a dance which is meant to formally introduces men and women in a socially acceptable manner) held at Mrs. Van Osburgh's conservatory, it is hot, and there are a lot of ugly women in it. Thus, in comparison, the train isn't so bad. There is an added implication that his company (which parallels the more socially acceptable matchmaking at the cotillion) also lends to it being considered overall a positive experience.