(A, B) Semithin longitudinal sections of the cornua in situ of a 0-day old and 9-day old drone, respectively. A: 2 different cuticle types, B: distribution of the secretion. (C) Semithin section of an everted cornua. CtI, cuticle with indentations; CtS, smooth cuticle; FC, fat cells; S, secretion; epS, epithelium on the side of the smooth cuticle; epI, epithelium lining the cuticle with indentations.