The female genitalic region and gonoducts of Embioptera (Insecta), with general discussions on female genitalia in insects

The exoskeleton of the female postabdomen, including the external genitalia and ectodermal gonoducts, was studied in five phylogenetically distant species of Embioptera from the genera Metoligotoma (Australembiidae), Clothoda (Clothodidae), Aposthonia (Oligotomidae), Biguembia (Archembiidae), and Enveja (without family assignment). The morphological interpretation of the embiopteran postabdominal sclerites and gonoduct components is discussed in a wider context of Insecta. This includes some issues of general importance, such as effects of the translocation of the gonopore from venter 7 to venter 8, the definition of gonopore location, and the definition of the vagina. We then compare the five study species regarding their postabdominal morphology, and define characters that can be used for future phylogenetic and taxonomic work on Embioptera; the corresponding character states are presented in a matrix. Important results on Embioptera are as follows. (1) The gonopore appears to lie in the posterior part of venter 8, but this apparent location probably only results from the median parts of venter 8 having been formed from an extension of venter 7. (2) The ectodermal gonoducts consist of a common oviduct and an extended oviduct, while there is either no vagina or only a very short and wide one. (3) In contrast to earlier reports, accessory glands are absent from venter 9 (although there may be vestiges in Enveja). (4) No support was found in female genital characters for the conventional view that the Clothodidae are the sister group of the remaining Embioptera; instead, we report several character states suggesting Metoligotoma as sister to the remaining Embioptera.