Who is Gertrude and Hilda from Factotum and what is their importance?

Gertrude and Hilda are two pink, scrubbed boarders in Mrs. Downing's boarding house in St. Louis, Gertrude and Hilda check on Henry Chinaski after they hear him vomiting. Henry takes a liking to Gertrude, kind-faced, dark-haired, and cute, with perfect legs and wearing a low-cut blouse. Hilda blushes a lot. Henry finds that Gertrude drips of sexuality, despite her girlish, perfumed room he visits once for a moment. They go out once for drinks and return angry. Henry is sure neither will have trouble attracting a husband when the troops come home. When Henry announces he is moving back to Los Angeles, Gertrude introduces him to her boyfriend Joey.