A female cockroach can be differentiated from a male cockroach, due to the presence of

In females, the 7th sternum is boat shaped and together with the 8th and 9th sterna forms a brood or genital pouch.The abdomen in both males and females consists of 10 segments.In both sexes, the 10th segment bears a pair of jointed filamentous structures called anal cerci.Males bear a pair of short, threadlike anal styles which are absent in females.