Final answer:
Morticia's reaction to hearing that the Beinekes are coming for dinner can be described as feeling worried, grieved, and uncomfortable during dinner.
Step-by-step explanation:
Morticia's reaction to hearing that the Beinekes are coming for dinner can be seen in the text:
Dinner was an agony. She had made a hasty attempt with a curling-iron, and burned her finger and much hair. She could see that her aunt was both worried and grieved, and her uncle kept saying, "Well, I'll be darned!" over and over in a hurt and faintly hostile torte. And Marjorie sat very quietly, intrenched behind a faint smile, a faintly mocking smile.
Morticia's reaction can be described as feeling worried, grieved, and uncomfortable during dinner. She is aware of her aunt's and uncle's negative responses to the news of the Beinekes coming and feels the tension in the air.