In the mouth parts of a cockroach, the labium forms $\underline{\text{I}}$ while$\underline{\text{ii}}$ acts as a tongue.

Answer: DSolution: The mouth parts of cockroach are of biting and chewing type consisting of labrum (uuper lip), pair of mandibles, a pair of maxillae and a labium (lower lip) Within the oral cavity enclosed by the mouthparts, lies a median flexible lobe called hypopharynx (tongue).