Abstract Coccinellids typically do not show exaggerated sexual dimorphisms, and the only reliable sexing methods for some species have been dissection and behavioral observations. Behavioral methods can potentially lead to sex identification but are very time consuming, require exposing sexually naive individuals to conspecifics, and risk incorrect identification since homosexual mounting in these species has been observed in the laboratory. Research involving use of live specimens requires techniques to non-invasively determine the sex of individuals, but such methods have not been clearly or fully described in the literature. Closer examination of the species Coccinella novemnotata Herbst, Coccinella septempunctata L., Coccinella transversoguttata richardsoni Brown, and Coccinella trifasciata perplexa Mulsant has led to the discovery of a reliable and efficient way to differentiate the sexes by looking at the shape of the seventh sternite (fifth visible), and this method has been demonstrated to be 100%...