Structural Organisation in Animals — BIOLOGY STD 11 Science — Question

It is a narrow opening that lies at the base of the preoral cavity. It is bounded by the mouth parts and leads into the pharynx. The mouth parts of cockroach are of biting and chewing type. They also help in swallowing. The mouth parts are attached to the head capsule. The mouth parts include the following structures:

1. Labrum is also called upper lip that helps in holding food particles during feeding.
2. Mandibles lie on the sides of the mouth just behind the labrum. The two mandibles work against each other in a horizontal plane to crush and cut the food into pieces.
3. First maxillae are a pair of maxillae that lie beneath the andibles, one on either side of the head.
4. Second maxillae or labium is also called lower lip. It is a single structure, but it is formed by the fusion of a pair of second maxillae. It lies behind the mouth and forms a type of lower lip.

A median flexible lobe, acting as tongue (hypopharynx) lies within the cavity enclosed by the mouthparts.