Catholic Encyclopedia (1913)/Mantelletta
An outer vestment reaching to the knees, open in front, with slits instead of sleeves on the sides. It is worn by cardinals, bishops, and prelates di manteletta. For cardinals the colour is ordinarily red, in penitential seasons and for times of mourning it is violet, on Gaudete and Laetare Sundays rose-colour; for the other dignitaries, the same distinctions being made, the colour is violet or black with a violet border. Cardinals and bishops belonging to orders which have a distinctive dress, also abbots who are entitled to wear the mantelletta, retain for it the colour of the habit of the order. The vestment is made of silk only when it is worn by cardinals or by bishops or prelates belonging to the papal court. The mantelletta is probably connected with the mantellum of the cardinals in the "Ordo" of Gregory X (1271-1276) and with the mantellum of the prelates in the "Ordo" of Petrus Amelius (d. 1401), which was a vestment similar to a scapular.
The mantellone, the outer vestment of the prelates, differs from the mantelletta by being longer and having wing-like sleeves.