Ultrastructure of the epithelium lining the smooth cuticle of the cornua glands. (A) Detail of the apical region in a pupa of 11 days. (B) Detail of the cytoplasm in a pupa of 13 days. (C) Detail of the cytoplasm in a just emerged drone. d, desmosomes; CtS, smooth cuticle; CtI, indented cuticle; MV, microvilli; mt, mitochondria; GA, Golgi apparatus; Nu, nucleus; RER, granular endoplasmic reticulum.