Biology XI: 7 Stru Orgn in Animals(6 Morphology of the Cockroach)

Morphology of the Cockroach Belongs to: Phylum Arthropoda Class Insect Genus Periplaneta Species Americana Brown or black-bodied animals. Size ranges from 0.6 cm to 7.6 cm Nocturnal; omnivores; live in damp places Have long antennae; flat extension of upper body that conceals the head Serious pests and vectors of several diseases Morphology Adults 34−53 mm long; wings extend beyond the tip of the abdomen in males Body segmented; covered by chitinous exoskeleton (brown-coloured) At each segment, the exoskeleton has sclerites (hardened plates). Sclerites are called tergites dorsally and sternites ventrally. Sclerites are joined by arthrodial membrane (thin and flexible articular membrane) Head Triangular shape Lies anteriorly at right angles to the body axis Formed by the fusion of 6 segments Shows great mobility in all directions due to a flexible neck Head capsule contains: A pair of thread-like antennae (sensory) A pair of compound eyes Biting and chewing type of mouthparts are formed by appendages present on the anterior part of the head. Tongue (hypopharynx) lies within the cavity enclosed by the mouth parts. Thorax Abdomen Present in both males and females; contains 10 segments In females: 7th sternum; boat-shaped The 7th, 8th and 9th sterna form the genital pouch (brood). Anterior part of genital pouch contains gonophores, spermathecal pore and collateral glands. In males: Genital pouch lies at the hind part of the abdomen Genital pouch is bound dorsally by the 9th and 10th terga, and ventrally by the 9th sternum. Genital pouch contains dorsal anus, ventral male genital pore and gonopophysis. Bear a pair of short, thread-like anal styles which are not present in females In both sexes, the 10th segment has a pair of jointed, filamentous anal cerci.