help finding a gemara

Someone (ds) emailed me the following to post on the blog. Any help would be appreciated. My memory isn't so good but maybe someone else remembers to what he is referring.

I would appreciate if you can post my question thanks.

I started learning Bruchois and Shabbos with the daf yomi on the cd daf, I came across a gemeruah or at least that the maggidei shiur read with the actual text, its so clearly in my mind that I even think I remember the layout of that daf, I confirmed with my friend who also learned the daf and he too told me that he remembers it from Bruchois and Shabbos, but both of us couldn’t find it. Don’t get me wrong we tried for hours on end.

I did find that it’s the last piece in Makkos. (in Makkos it doesn’t reference back to Shabbos or Bruchois) I would appreciate if anyone can help me.

The gemruah says a story of when R' Akiva with other tannuim came up to Yerushaleim after the Chorbin when they saw it, they rant their cloths, when they came to the beis hamikdoish they saw a fox emerge. The tannuim started crying while R' Akiva started laughing…….they asked why are you laughing? he asked why are you crying? He said that since the Nuvi Yermiah became true so too will the Nuvi Zachari where it says "old men and women will……" (Zachari 8)

Any help would be appreciated it, but remember only in Bruchois or Shabbos.