The female postabdomen and internal genitalia of the basal moth genus Agathiphaga (Insecta: Lepidoptera: Agathiphagidae): morphology and phylogenetic implications

The female postabdomen of Agathiphaga vitiensis terminates in a telescope‐type extensible oviscapt with an apial ‘oviscapt probe’ composed of fused segments behind VIII. Exceptionally within the Lepidoptera two pairs of long ‘anterior apophyses’ arise from segment VIII, from the dorsum and venter. Agathiphaga has the most elaborate postabdominal musculature recorded from female Lepidoptera, comprising 24 muscle sets of which nine may be family autapomorphies. Apophysis musculature does not permit unambiguous homologizing of the single anterior apophysis in Lepidoptera–Glossata with either the dorsal or ventral pair in Agathiphaga, but is compatible with an interpretation of the glossatan anterior apophyses as a composite formation. Nine muscle sets shared with rhyacophilid caddisflies are ascribed to the amphiesmenopteran ground plan. The spermathecal duct represents an intermediate stage between the simple type present in Micropterigidae and the ‘two‐compartment type’ characteristic of almost all other Lepidoptera. The spermatheca has no lagena. The bursa copulatrix is small and simple. Accessory glands are very large, simple sacs. There are 40 + ovarioles per ovary. A terminal cloaca is extremely short. The numerous ovarioles potentially support a sister‐group relationship between Agathiphagidae and all other Lepidoptera, whereas the spermathecal duct histology supports the alternative conservative placement of the family as sister group of all nonmicropterigid Lepidoptera. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 159 , 905–920.