Differentiate between tergum and a sternum.

Explanation

1. In cockroach the entire body is covered by a hard, brown coloured, chitinous exoskeleton.
2. In each segment, exoskeleton has hardened plates calledsclerites, which are joined together by a delicate and elastic articular membrane called arthrodial membrane.
3. The sclerites of the dorsal side are called tergites (singular- tergum), those on the ventral side are called sternites (singular- sternum) and those of lateral sides are called pleurites