Ashok Ji,
From the above list, I was able to verify the following for the presence/absence of the subhAshita in question.
1. chANakya-nIti-darpaNaM : negative
2. chANakya-nIti-sAstraM : negative
3. bhartR^hari's three nItI-s : negative
4. vR^ddha chANakya - half of it : negative
have no access to the rest of chANakya's works mentioned by you nor of bhartR^hari's sayings outside of nIti-trayI. Also please note that 1 and 2 above are the largest collections of chANakya besides artha-sAstra. Therefore if the subhAsita in question is absent in the 3 primary sources on chANakya, chances of it being available in any of the rest is very bleak. likewise is the case about bhartR^hari.
meanwhile,
viSNu-Sarma's panchatantra - positive
nArAyaNa paNDita's hitopadesa - positive
tone in both of the above is indeed as explicitly 'quoting' from an earlier source, in a sense of proving a point by authority of an established and well known nIti... therefore the question remains where from?
From the above list, I was able to verify the following for the presence/absence of the subhAshita in question.
1. chANakya-nIti-darpaNaM : negative
2. chANakya-nIti-sAstraM : negative
3. bhartR^hari's three nItI-s : negative
4. vR^ddha chANakya - half of it : negative
have no access to the rest of chANakya's works mentioned by you nor of bhartR^hari's sayings outside of nIti-trayI. Also please note that 1 and 2 above are the largest collections of chANakya besides artha-sAstra. Therefore if the subhAsita in question is absent in the 3 primary sources on chANakya, chances of it being available in any of the rest is very bleak. likewise is the case about bhartR^hari.
meanwhile,
viSNu-Sarma's panchatantra - positive
nArAyaNa paNDita's hitopadesa - positive
tone in both of the above is indeed as explicitly 'quoting' from an earlier source, in a sense of proving a point by authority of an established and well known nIti... therefore the question remains where from?