Fine Structure of the Wax Gland in a Scale Insect, Eriococcus lagerstraemiae KUWANA (Homoptera : Ericoccidae)

Abstract

The dorsal surface of the female Ericoccus lagerstraemiae is covered by a thick shield made of long, thin, tubular wax filaments. The integumentary wax gland producing these filaments are distributed throughout the dorsal surface. Each gland is composed of a cuticular duct, one large main cell, six lateral cells and a ductule cell. The main cell stores in its reservoir a massive secretory substance which shows positive reactions to the tests for lipids, proteins and carbohydrates. The cytoplasm of the main cell contains well-developed rough-surfaced endoplasmic reticulum and numerous secretory globules which are discharged into the lumen of the reservoir. The lateral cells may also contribute some secretion to the covering wax filament, but their precise role is unknown. The ductule cell contains a thin cuticular ductule which is formed by the cell itself. The formative mechanism of the tubular filament is of special interest. The amorphous secretory substance is transported from the main cell to the bottom of the cuticular duct via the ductule, met by the secretion of the lateral cells there, and then is molded into a tube by the trough-shaped cast cuticle present there.