The question "Minah Hani Mili?", with reference to the Beraisa that the Gemara just cited, is asking from where we know that Eidim Zomemin of a ben Gerushah or ben Chalutzah receive Malkos, rather than doing to them what they attempted to do to the defendant (i.e. declare them b'nei Gerushah or b'nei Chalutzah).

Be'Virchas Kol Tuv,

Eliezer Chrusler