(adv.) By rites, or by a particular rite.

bleakly ceremoniously decorously demurely dismally drearily earnestly formally funereally gloomily grandly gravely grimly heavily imposingly in due form in set form loftily magisterially majestically nobly pro forma regally ritualistically ritually royally sadly sedately seriously sober-mindedly soberly sobersidedly somberly sombrously staidly stately thoughtfully venerably with dignity worthily