This study provides a detailed analysis of the male reproductive system of Mylabris cernyi, contributing to a broader understanding of the morphology of the blister beetle. The male reproductive system of M. cernyi consists of an aedeagus, 2 seminal vesicles, 2 vasa deferentia, an ejaculatory duct, 3 pairs of accessory glands, and 2 testes. We examined the structure of these organs using optical and electron microscopy. The testes contain 14–15 radially arranged follicles, with distinct maturation, growth, and differentiation zones progressing from the periphery to the center. The testes give rise to the vas efferens, which subsequently join to form the seminal vesicle and vas deferens. The lumens of the vesicles contain mature sperm masses. There are 3 pairs of accessory glands (Ag1, Ag2, and Ag3). Ag1 is a short, tubular, light yellow gland with columnar epithelium and a muscular layer that secretes basophilic materials. Ag2 is long, coiled, and whitish, containing both basophilic and fibrous secretions, with a squamous epithelial layer. Ag3 is a long, coiled gland that produces eosinophilic chemicals. These glands open into the ejaculatory duct, which is lined by an epithelium, thick muscle layer, and intima. The inner surface of the intima is covered with spines. The aedeagus is the external opening of the ejaculatory duct. This study represents the first morphological description of the male reproductive system of M. cernyi and provides valuable insights for future research in this field.
