Structure and development of the internal male reproductive organs in the dragonfly Tramea virginia (Rambur).

The internal male reproductive organs of Tramea virginia consist of a pair of testes, a pair of vasa deferentia (which in adult modify distally into seminal vesicles), a median sperm sac and a short ejaculatory duct. The development of the genital tract occurs in the ultimate nymph. Each testicular lobule contains the gametes showing collectively only a single stage of spermatogenesis. The process of spermatogenesis is vigorous in the ultimate nymph and, therefore, the newly emerged imago contains active spermatozoa in its testicular lobules. Spermatophores are not observed in the genital tract of the adults.