Sinclair, Bradley J., Borkent, Art & Wood, D. Monty, 2007, The male genital tract and aedeagal components of the Diptera with a discussion of their phylogenetic significance, Zoological Journal of the Linnean Society 150 (4), pp. 711-742 : 725

publication ID 10.1111/j.1096-3642.2007.00314.x

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Description ( Fig. 6D, E View Figure 6 )

Testis: Each testis is long, slender, and spindleshaped, often yellowish-orange in dissections. The testes of Ptychoptera nr japonica Alexander and Ptychoptera contaminata (L.) are positioned far posteriorly, lying near the accessory gland complex.

Epididymis: Not differentiated.

Vas deferens: In Ptychoptera lacustris Meigen ( Fig. 6E View Figure 6 ), the vasa deferentia extend posteriorly to the level of the posterior chambers of the accessory gland complex, where they turn medially, fuse, and run anteriorly before arching abruptly into the accessory gland complex ( Just, 1973). In Ptychoptera contaminata , the vasa deferentia appear little differentiated from the testes, extending first anteriorly dorsal to the testes. The vasa deferentia of Ptychoptera nr japonica ( Fig. 6D View Figure 6 ) also run immediately anteriorly and empty into the apex of a large three-chambered accessory gland complex.

Accessory gland and seminal vesicle: In Ptychoptera lacustris , the accessory gland complex is divided into an elongate and slender anterior section connected to a rounded posterior gland by a short duct ( Fig. 6E View Figure 6 ). The accessory gland complex of Ptychoptera nr japonica ( Fig. 6D View Figure 6 ) is fused along the midline, forming a three-chambered gland. In Ptychoptera contaminata , the genital tract is folded over itself several times and what appear to be vasa deferentia could in fact be additional sections of the accessory gland complex lying beneath paired, rounded chambers. In this species, the vasa deferentia are quite elongate, extending anteriorly before strongly arching posteriorly as clear, thin-walled ducts that separately enter the paired posterior chambers.

Ejaculatory duct: The ducts are short, lined with thick muscles, and unite prior to entering the sperm pump ( Just, 1973). The ejaculatory ducts of Ptychoptera nr japonica and Ptychoptera contaminata are bent sharply upon exiting the seminal vesicles and then arch to the sperm pump.

Ejaculatory apodeme, sperm pump, and aedeagus: Ptychoptera lacustris and Ptychoptera contaminata possess a large median ejaculatory apodeme and a pair of apodemes extended from the paramere, which compress the sperm pump [see explanation in Just (1973)]. In contrast, Ptychoptera nr japonica possesses a large sclerotized, spherical sperm sac and lacks an ejaculatory apodeme [similar to that of Bittacomorpha clavipes (Fab.) ; see Wood (1991: fig. 10)].

Remarks: The genital tract is quite variable in the genus Ptychoptera . The configuration of the vasa deferentia is similar to that observed in Bibionomorpha and Culicomorpha . The accessory gland complex comprises a number of chambers that are separated, connected by slender ducts or fused into a single gland.