The fine structure of the colleterial glands of Hyalophora cecropia (Lepidoptera)

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Abstract
The structure of cells in the colleterial glands of the Cecropia silkmoth was examined. Morphologically and functionally the gland is divided into two regions, a tubular one in which columnar protein‐synthesizing cells are located, and an expanded region in which flattened cells with very different structure are most prominent. The fine structure of the latter cells which are presumed to secrete a phenolic glucoside, closely resembles that of cells described in the colleterial glands of orthopterans. The protein‐secreting cells have many features normally associated with pancreatic acinar, and other cells of similar function. Among these are extensive rough endoplasmic reticulum, an elaborate Golgi complex, and a modest number of mitochondria. Other features which are less usual in cells of this type are an elaborate secretory apparatus consisting of a cuticular tubule inserted into a microvilli‐lined cavity at the apical end of the cell, and large numbers of cytolysomes, myelin figures, and lipid droplets. A chitogenous cell with a very distinct and specific type of ultrastructure is found associated with the secretory cell. This cell type is attached to the cuticular elements of the gland, and the main features of its cytoplasm are extensive bundles of microtubules which presumably serve as supportive elements for the secretory cells.