It is accepted that male genitalia are not diagnostic, spermatheca are partly diagnostic within the genus Cassida Linnaeus, 1758. However, so far, it appears that genital studies are based solely on stereo microscopy. Ultrastructures of genitalia have been not studied except for a few studies. In this study, female genital structure belonging to three Cassida atrata Fabricius, 1787 specimens collected from Kayseri and Nigde provinces in 1996 and 2018 from Turkey was examined for the first time in SEM in order to determine whether ultrastructural studies are useful from taxonomic point of view. Thus, new diagnostic characters were obtained and it revealed that it was diagnostic for species in other subgenus. Photos of spermatheca taken by both SEM and stereo microscope are also given.