"Apropos the removal of chasuble and maniple: I later learned that the ICRSS do that in Italy as well, but the FSSP do not."

I believe that the ICRSS priests in the U.S. do this also, as did--it appears in posted photos--Msgr. Wadsworth at this year's Mater Ecclesiae Mass of the Assumption in Philadelphia's Cathedral Basilica.

My (limited) understanding is that the celebrant may remove the chasuble (in addition to the maniple) if the pulpit at which he is to preach is *outside* the sanctuary. If, however, he preaches from a simple ambo *within* the sanctuary (or simply stands on the predella, Gospel side, facing the people), he does not have to remove the chasuble, but simply removes the maniple. But I'm not really a rubricist, so am willing to stand corrected. Anyone know for sure? Is this merely a matter of local custom?

I believe I once saw an FSSP priest do this in North America - but he had newly arrived from Europe. None of the others do it - just take off the maniple

The ICRSS in the US commonly remove the chasuble as well as the maniple, in my experience. Br. Morrison's note is interesting though; at the locale where I have attended the most ICRSS services, the ambo is outside the Sanctuary. That being said, the priest informed someone who asked in my presence that it is because preaching is a priestly act but not a liturgical act - no reference to Sanctuary vs. not Sanctuary.

Would someone point out the rubric that prescribes the removal of the maniple. I don't believe it exists.

It's a rule that rests on the authority of some renowned liturgists, e.g. de Herdt: “DE CONCIONE. Si ipse Celebrans sit concionaturus in cathedra, semper casulam et manipulum deponit vel in sacristia, vel potius in plano ad cornu Epistolae, et minus congrue in Altari ad cornu Epistolae. (...) Si Celebrans concionetur ad Altare, vel retinet casulam et manipulum, vel illa deponit super Altare in cornu Epistolae, et potius in plano ad cornu Epistolae”.

It seems to have started with St. Charles Borromeo (Concilium Mediolanense IV): “Parochi vero, Praepositi et alii Episcopo inferiores, cum in altari id munus obibunt; tunc capite aperto stare debebunt ad sacerdotalis libri praescriptum. Quo autem facilius a frequenti populo audiantur, suggestum eos ascendere opportunius erit; tuncque casulam deponere, si maluerint, licebit: quam statim sermone habito ad altare reversi induant”.

Thank you, sampras, for tracking down the rubricist. Unfortunately, the authority of one rubricist can be cancelled out by that of another. In the final analysis, there is no rubric that prescribes the removal of the maniple or chasuble, though I completely understand if, for practical reasons, a priest wishes to remove either.