According to the sentences from paragraph 3 of “The Negro Artist and the Racial Mountain, the narrator talks about how a so-called high class Negro still longs to be like the white man, abandoning his racial identity.
The words that best replace the underlined word "aping to" to retain the same meaning is "imitation of".
This is because, the meaning of the word "aping" means to copy someone or something in a weird, unusual way.
