In this connection Srila Bhaktisiddhanta Sarasvati Thakura again quotes the following verse from the Sahitya-darpana (6.288):

Thus the technical names for the five kinds of introductory scenes of the drama are listed as udghatyaka, kathodghata, prayogatisaya, pravartaka and avalagita. When Srila Ramananda Raya inquired which of these five Srila Rupa Gosvami had used to accomplish the technical introduction to his drama Lalita-madhava, Rupa Gosvami replied that he had used the introduction technically called udghatyaka. According to Bharati-vrtti, three technical terms used are prarocana, vithi and prahasana. Thus Rupa Gosvami also mentioned vithi, which is a technical term for a certain type of expression. According to the Sahitya-darpana (6.520):

The vithi beginning of a drama consists of only one scene. In that scene, one of the heroes enters the stage, and by means of opposing statements uttered by a voice from the sky (offstage), he introduces the abundant conjugal mellow and other mellows to some degree. In the course of the introduction, all the seeds of the play are planted. This introduction is called udghatyaka because the player dances on the stage. This term also indicates that the full moon enters the stage. In this case, when the word natata ("dancing on the stage") is linked with the moon, its meaning is obscure, but because the meaning becomes very clear when the word natata is linked with Krsna, this type of introduction is called udghatyaka.