Abstract
Fine structure of the integument in the silkworm larvae was studied in thin sections with electron microscope, using ‘S mottled’ strain. In the outer endocuticle dense bands of laminae having average thickness of 0.3μ ranging from 0.2 to 0.4μ were observed, and the dense bands are made up of double layers.
From the light and electron microscopical studies on the cuticle of the silkworm, it has been postulated that Ito's ‘wedge-shaped structure’ should be called pore canal. The pore canals in the silkworm are arborescent near their outer ends, and the shape is similar to that of Ephestia and Diataraxia. They are 2-6μ in diameter and 10-20μ in length, and filled up with filamentous substance.
In some parts of the endocuticle, thread like substance which has the appearance of micro protrusion from epidermal cell was observed in the electron micrograph.
Dense bodies supposing to be composed of melanin pigments or osmophillic substances such as lipoprotein, were observed only in the outer endocuticle of the melanin pigmented part.
In the epidermal cell, mitochondria showing similar structure to that of other insects or mammals were observed. Besides, unidentified bodies, which may be called ‘granulated bodies’ are observed in the cell.
