Every tegmina of a cockroach has sclerites which are analogous to the bones of humans.
Every abdominal segment of cockroach consists of two lateral sclerite plates called pleura along with a dorsal terga and a ventral sterna. But what will be the case with the last body segment where 10th sternum is absent?
I mean will, there be any pleuron in the tenth segment because, following our textbook, pleura serve for articulation among sterna and terga and also spiracles are present in the first eight abdominal segments but the 10th sternum is absent in Periplaneta americana.
Actually there is no evidence of the presence of any pleurons in the last segment in our text book.
Moreover, there are no abdominal spiracles in the 9th and 10th segments so there is no particular reason to say that pleura are present in the 9th and 10th segments as well.