Specialization of the endoplasmic reticulum in the apex of the midgut cells of Aeshna cyanea (Insecta, Odonata).

Lamellar stacks of cisternae regularly spaced and bound to each other by fine filaments are observed in the apex of midgut cells of Aeshna cyanea. These cisternae are connected with the rough endoplasmic reticulum but are devoid of ribosomes except on their terminal sacs. Their location and their structure, quite different in fed and starved animals, suggest that they are involved in intracellular transport.