A volatile female sex pheromone, secreted by the pygidial glands of Blattlla germaniea, which attracts males from a distance was studied. Ultrastructural studies showed common epidermal and canal cells associated with glandular cells, classified as class 3 secretory unit The thickness of pygidial glands from young virgin females Increased progressively and became larger, 10 to 13 days after adult emergence. It decreased markedly after mating and increased again after the release of the ootheca. Based on the morphology of the glands, it was further observed that B. germaniea young virgin females' attractiveness increased gradually, such attractiveness decreased at mating. After larval emergence, females' attractiveness wasonce more enhanced. Dkhktromethane extracts of pygidial glands attracted males from a distance. These results demonstrate the pheromone gradual secretion and similarly pygidial glands evolution during adult emergence.
