The Morphology and Histology of New Sex Pheromone Glands in Male Scorpionflies, Panorpa, and Brachypanorpa (Mecoptera: Panorpidae and Panorpodidae)
The n~orphology and histology of a previously undescribed sex pheromone gland in male scorpionflies of the genus Panorpa (Mecoptera: Panorpidae) and a morphologically similar gland in Brachypat~orpa (Mecoptera: Panorpodidae) are described and discussed. The gland and the associated pheromone dispersing structure consist of an eversible pouch that lies in the ventral part of the male genital bulb at the point where the basistyles diverge. The glandular layer of epithelium is composed of three types of cells that vary in size between species of Panorpa and between Panorpa and Brachyponorpa. It is suggested that the gland may have evolved from a structure that is everted by the male during copulation and used to push the female's terminal abdominal segments out of the way and/or open the female genital aperture.