The female reproductive system in Frankliniella fusca (Hinds) consists of 2 ovaries of 4 panoistic ovarioles each, 2 lateral oviducts, a common oviduct, a vagina bearing a spermatheca and opening to the exterior on the 8th segment, and an accessory gland. The imaginal ovipositor comprises a pair of 1st valvulae pertaining to the 8th segment and a pair of 2nd valvulae pertaining to the 9th. The 1st valvifers and 3rd valvulae of other insects are absent.

The female reproductive system in Haplothrips verbasci (Osborn) is similar to that of F. fusca, but there is no accessory gland or vagina, and the ovipositor is reduced to a U-shaped chute at the back of the 8th sternum.

The postembryonic development of these structures and their musculature is described and is compared between the 2 species and with that occurring in other insects. All structures are of ectodermal origin except for the ovaries and the lateral oviducts, both of which arise in the embryo.

The imaginal morphology of the female system in F. fusca and the details of its development are similar to those of other Exopterygota, but its delayed ontogeny recalls endopterygote morphogenesis.

The structures absent in the adult of H. verbasci were likely present in some phlaeothripid ancestor, since there are developmental vestiges of them in the preimaginal instars of this species. The ovipositor of H. verbasci is probably homologous with the first valvulae of F. fusca, since it has a paired origin on the eighth sternum.

A peculiar “anal tube” is present in the first 3 instars of both sexes of F. fusca but is absent in the same instars of H. verbasci.