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: 722

publication ID 10.1111/j.1096-3642.2007.00314.x

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Description ( Figs 2D View Figure 2 , 5A View Figure 5 )

Testis: Each testis is oval to pyriform, with a thin epithelium continuous with the vasa deferentia.

Epididymis: Not differentiated.

Vas deferens: The vasa deferentia extend posteriorly to the base of the accessory glands, where they arch medially. Each duct abruptly terminates near the anteromedial margin of the accessory gland ( Neumann, 1958; Dahl, 1980).

Accessory gland and seminal vesicle: The accessory glands are paired spherical structures, divided internally into two functionally different chambers ( Neumann, 1958; ‘Samenblase’). The chambers are lined with columnar cells, producing secretions that empty separately into the duct that separates the seminal vesicle and the ejaculatory duct. No spermatozoa have been observed within the chambers of the accessory gland ( Neumann, 1958). The seminal vesicle is interpreted to occur at the apex of each of the vasa deferentia, adjacent to and fused with the accessory glands ( Dahl, 1980). A narrowing of the duct separates the seminal vesicle from the anterior fork of the ejaculatory duct. The seminal vesicle and the accessory gland are enclosed in a continuous sheath of circular muscle ( Neumann, 1958).

Ejaculatory duct: Anteriorly, the ejaculatory duct is paired for a short distance before fusing into a single duct. The circular muscle is very thin and does not function as a pump ( Neumann, 1958).

Ejaculatory apodeme, sperm pump, and aedeagus: There is a small flexible ejaculatory apodeme at the base of a narrow sclerotized aedeagus ( Neumann, 1958; Wood, 1991). The ejaculatory apodeme rotates, compressing the sperm pump and forcing the spermatozoa out through the narrow opening of the phallotrema.

Remarks: The configuration of the male genital tract of the Trichoceridae   was thoroughly investigated by Neumann (1958). Our examination of material confirms his interpretation. The male genital duct of Trichoceridae   is somewhat similar to Culicidae   and Chaoboridae   in basic configuration and no preformed spermatophore is produced. Matsuda (1976) assumed that one of the chambers in the accessory gland corresponded to the seminal vesicle in Aedes Meigen. This   appears unlikely as spermatozoa are not stored in the accessory gland chambers of Trichocera Meigen.