An example of situational irony is when the colonel and girl were arguing over how woman panic quickly and a woman acted calm in the presence of a snake.
An example of dramatic irony is when the reader knew that the snake was present and the characters didn't. The hostess, who knew the whole time and stayed calm was the reason she proved the colonel wrong.
The theme of The Dinner Party is that it doesn't matter what gender you are. Both can be brave or cowardly, unlike what the colonel said.