Which of the following features is used to identify a male cockroach from a female cockroach?

Step-by-step solution

In male cockroach, the 9 th sternite bears a pair of small spine-like unjointed caudal or anal styles which are absent in female cockroach. The anal styles are believed to function as a motion detector. Besides this, the other three characters, i.e. anal cerci, boat-shaped sternum on 9 th abdominal segment and forewings with darker tegmina which are found in both male and female cockroaches.