Cockroach - Abdomen and Abdominal Appendages

Abdomen in both males and females consists of 10 segments. A typical abdominal segment has a dorsal tergum ventral sternum and between them a narrow membranous pleuron on each side which bears spiracles. In females the sclerites of 8th and 9^th are overlapped corresponding sclerites of the 7^th segment. The seventh sternum is boat shaped and together with eighth and ninth sterna forms a brood or genital pouch. In males only 8^th are overlapped by the 7^th segment. The tenth segment bears a pair of 15 jointed filamentous structures called as anal cerci. Ventral to these in the males, the 9^th segment bears a pair of short, thread like anal styles, which are absent in females. Between one sclerite and the other there is a flexible arthrodial membranes.

1. It is the largest and the broadest, relatively more flattened and softer part behind the thorax.
    
2. There are ten tergites. In both males and females, the 8th and 9^thtergites are mostly covered by the 7^th. The 10^th tergum is somewhat bowl-shaped and posteriorly bifurcated into two lobes.
    
3. Ventrally, the abdomen has 9 sternites in male and 7 in females.
    
4. In females the last sternite (7^th) is the larger and boat shaped and together with distinct 8th and 9th sternites it formes a chamber like structure called gynatrium, Posterior part of this chamber is called oothecal chamber. Behind this chamber, 7^th sternite bifurcates into two prominent oval plates called apical lobes. Female gonopore is located between them.
    
5. In males, the 9th sternite bears a pair of spine like anal styles.
    
6. In both male and female cockroaches, several small chitinous appendages are located around the ganopore. These help in reproduction and hence called gynapophyses.
    
7. At several places, certain processes of exoskeleton extend into the body and form endoskeletal elements which provide attachment to muscles and hence called apodemes.

Abdominal Appendages

1. Abdominal segments lack locomotory appendages. These are certain small structures associated with gonopore, which are different in male and female cockroaches.
    
2. The 10th tergite posteriorly bears a pair of many jointed anal cerci. They bear minute sensory hair sensitive to sound and other vibrations.
    
3. The 9th sternite of males bear, in addition, a pair of small and spine-like unjointed anal styles.