Ruth is the character who refers to "marching roaches" at the end of Act II, Scene One. This is the point at which Mama announces that she has taken the insurance money and bought the family a house in Clybourne Park.
Ruth is ecstatic with the news:
Well -- well! -- All I can say is -- if this is my time in life -- MY TIME -- to say goodbye...to these Goddamned cracking walls!...and these marching roaches!...and this cramped little closet which ain't now or never was no kitchen!...then I say it loud and good, HALLELUJAH! AND GOODBYE...
(The entire section contains 300 words.)