The structure of the fat body in normal and starved cockroaches as seen with the electron microscope

Normal fat-cells in Blaberus discoidalis Serv. are surrounded by a three-layered outer sheath of connective tissue up to 3 μ in thickness. The fibres of the middle layer are set at right-angles to those of the other two layers. The morphology of the sheath suggests that the tracheoblasts do not secrete the connective tissue. In the fat-cells the endoplasmic reticulum and Golgi membranes are only weakly developed. Mitochondria are present of normal appearance. The cells are packed by glycogen granules. The mycetomes are prominent; each bacterium is surrounded by a membrane.