Figure 3 in Morphology of the male reproductive tract in the water scavenger beetle Tropisternus collaris Fabricius, 1775 (Coleoptera: Hydrophilidae)

Figure 3 Histology of the male reproductive tract of T. collaris. (A and B) Cross section of the glandular region showing the tubular accessory gland (ag1) and bean-shaped gland (ag2). The arrowhead indicates the epithelial folds, and the arrows point to the region of the secretory epithelium. Note the secretion accumulated in the lumen of the beanshaped gland (asterisk). (C and D) Cross section of a seminal vesicle (sv) with simple epithelium (arrow), and lumen full of spermatozoa (asterisk). In (D) detail of the epithelium (ep) and the external muscular layer (m). Bars: A = 200 µm, B and C = 100 µm, D = 25 µm.