The male accessory reproductive glands and spermatophore in Hydrophilus olivaceus (Polyphaga-Coleoptera).

1 In Hydrophilus olivaceus two pairs of accessory glands of mesodermal origin are associated with the male reproductive apparatus. The inner pair of glands (AG1) are thin-walled, recurved tubes of uniform diameter. Their histology and histochemistry was described. They elaborate muco-or glyco-t proteins with no RNA component and some free glycogen. The mode of secretion is merocrine. The secretory products are used for the formation of sperm capsules packed inside the spermatophore and possibly for nourishing the spermatozoa. 2. The outer pair of massive, thick-walled accessory gland (AG2) is distinguishable into 4 zones of varied histological structure, which was described in detail. The powerful external muscular coat projects inwards in the form of septa that divide the secretory epithelial cells into compartments, each having its own lumen and all the lumina lead into a central lumen. The mode of discharge of secretory products involves both merocrine and holocrine methods. The secretory cells seem to undergo endopolyploid growth of their nuclei before participating in the synthetic activities. The secretory products of AG2 are muco- or glyco proteins that tend to be coupled with RNA. These are probably utilized for the formation of the massive eosinophilic ring and pigment granules that surround the helically coiled sperm column of the spermatophore. 3. Morphology and histology of the spermatophore, after its deposition in the female genital tract, was described in detail. 4. Possible mechanisms of spermatophore disintregration and its removal from the spermathecal barrel are discussed.