Mouth parts:
On the ventral side of the head mouth is present. The appendages surrounding the mouth which are helpful in feeding are called the mouth parts or trophi. The mouth parts of cockroach are chewing and biting type.
The mouth parts of Cockroach includes labrum (upper lip), mandibles, maxillae, labium (lower lip) and hypopharynx (tongue).
(i) Labrum:
This is also known as upper lip. It is a small flap like structure which covers the mouth dorsally. The inner surface of the labrum bears taste buds concerned with tasting of the food material.
(ii) Mandibles:
The mandibles are a pair of small triangular, stout unjointed sclerotized structures present on either side of the mouth. They have toothed inner edge helps in biting the food materials into small pieces. Hence treated as jaws.
(iii) Maxillae:
A pair of maxillae are present beneath the mandibles and treated as additional jaws. Each maxilla is differentiated into a basal segment consisting of cardo and stipes, terminal segment consisting of outer larger part called galea and inner stouter part called lacinia. The outer border of stipes bears long five jointed maxillary palp which is five jointed structure. The maxillae help in holding and pushing the food into the mouth during swallowing.
(iv) Labium:
The labium or lower lip lies behind the maxillae. It consists of proximal submentum, middle mentum and distal bilobed prementum. The mentum posses a pair of labial palps. The prementum bears a pair of outer paraglossae and a pair of inner glossae.
(v) Hypopharynx:
This is also known as lingua. It represents the tongue of the cockroach. It is a cylindrical and tubular structure present above the labium between maxillae. Common salivary receptacular duct opens at its base.
