Rasarnavasudhakara 3.398.p2

3.398.p2

atra nepathya-gataiḥ pātraiḥ prayogānucitasya vānara-viplavādy-arthasya sūcanād iyaṃ madhya-cūlikā |

Here, since an event unsuitable for stage representation—such as the rampaging of a monkey—is indicated by characters behind the curtain, this is an intermediate curtain-speech (madhyacūlikā).