四分比丘戒本疏 2.116

2.116

七八覆頭戒，《祇》云「和上闍梨前不得覆頭坐。風寒等不得全覆，當覆半頭一耳，見長老當挽却。」

Rules seven and eight, on covering the head: the Mahāsāṃghika-vinaya says: "Before an upādhyāya or ācārya, one must not sit with the head covered. During wind and cold and the like, one must not cover it completely; one should cover half the head and one ear. Seeing an elder, one should pull it back."