The sex-pheromone-producing gland in female Trichoplusia ni (Hübner) is a modified intersegmental membrane and the gland cells are ductless. Lipid spheres are located throughout gland cells and vary both in number and size relative to the age of the female. Most of the lipid is surrounded by oval to elongate distensions of smooth tubular endoplasmic reticulum which contain the enzyme catalase and are thus microperoxisomes. Lipid spheres evert the apical plasma membrane between microvilli, move away from the gland cells, and are stored in the cuticle as discrete lipid deposits. These deposits, in turn, move to the surface of the gland by tubular structures that differ from epicuticular filaments.