In tkam- 4. what do we learn about the ladies in the missionary circle from their discussion of the mruna tribe and the african americans in maycomb?

Based on their discussion, the ladies in the missionary circle prove they are ignorant hypocrites. 

A missionary circle SHOULD be about doing good for others in the name of charity. This circle, however, seems to be only good for gossip. They believe that Africa is full of "sin and squalor" and their words indicate they are extremely prejudiced.

They should be behaving like good Christians but their discussion proves they are not -- especially when one criticizes a servant for not being a good Christian.