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Cockroach Cockroach is a common insect living in warm humid places. Cockroaches are quite common in kitchens, bathrooms, gutters and hotel kitchens. They are nocturnal. They are spread worldwide. The scientific name of cockroach is Periplanata americana. Phylum - Arthropoda. Class – insecta Order Dictyoptera es. Cockroaches el kitchens. They ific name of External characters The body of cockroach is long, dorso-ventrally flattened and of reddish brown colour. An adult cockroach is 25 to 45 mm long and 8 to 12 mm broad. The size of male is slightly bigger. The body is protected by an exoskeleton of hard and chitinous material called sclerites. Sclerites are arranged as terga and sterna in all segments of the body. The body is clearly divided into three parts head, thorax and abdomen. . Head The head of cockroach is triangular. It is located at the anterior end and is almost at a right angle to the rest of the body . The head is formed by fusion of six segments. A pair of sessile compound eyes occur on the head. Eyes are kidneyshaped. Two long antennae occur. Antennae can be rotated in all directions At the anterior end of head, mouth is located.Mouth parts consist of a pair of mandibles, a pair of first maxillae, lubium , labrum and . hypopharynx. Salivary glands open at its basal region. Thorax •Thorax consists of three segments prothorax, mesothorax and metathorax •One pair of walking legs having five segments ie. Coxa, trochanter, femur, tibia & tarsus. •The first pair of wings develops from the dorsal side of mesothorax. These wings are horny and protective. •The second pair of wings develops from the dorsal side of metathorax. Abdomen • Abdomen is made up of ten segments. Each segment has a dorsal tergum, a ventral sternum and lateral pleurae. • A pair of anal cerci are associated with the tenth tergum. Anal cerci are phono-receptor structures. • In male cockroach, a pair of anal styles develop from ninth sternum. • In female cockroach, the eighth and ninth sterna jointly form a genital pouch. The seventh sternum is keel-shaped. • The male genital opening occurs in mid-ventral region of ninth segment. The female genital opening opens in the eighth segment. Digestive System • The alimentary canal of cockroach is divided into three parts Foregut, midgut and hindgut. • The cavities of foregut and hindgut are lined with cuticle. Mouth is located at the posterior end of a preoral cavity which is surrounded by mouthparts. • Pharynx follows the mouth. Salivary glands open on the ventral side of hypopharynx. • Oesophagus follows pharynx. The posterior region of Oesophagus expands and forms a crop • The crop opens into a gizzard. The wall of gizzard is muscular. •There are six chitinous teeth in its cavity. Food is grinded in gizzard. •At the posterior end of gizzard a sieve-like structure occurs which is formed by chitinous bristles. •The region upto gizzard constitutes fore-gut. Gizzard opens into midgut. •Eight, tubular hepatic caeca occur in midgut. They secrete digestive juices. •Midgut opens into hindgut where malpighian tubules are present. These act as excretory organs. •Rectum opens to the outside through anus located under the tenth tergum. The circulatory system • The circulatory system of cockroach is of 'open' type, called haemocoel • It consists of plasma and cells known as hemocytes. • In the thoracic and abdominal region, a tubular structure made up of thirteen funnel-like units, occurs along the middorsal region. This keeps the blood circulating. • The first three units occur in thorax and the remaining ten occur in abdominal region. Each unit can be considered a heart. THE RESPIRATORY SYSTEM • The respiratory system of cockroach is well developed. It consists of a branched network of tracheal tubes spread throughout the body. • The tracheal tubes open on the surface of the body through openings called spiracles. Ten pairs of spiracles occur. • Two pairs of spiracles occur in thoracic region and eight pair of spiracles occur in the abdominal region. The excretory system • The excretory units are malpighian tubules present at the union of midgut and hindgut. • They absorb nitrogenous waste and empty them into the cavity of hindgut. • Special nephrocyte cells and fat bodies also help in excretion. • Some excretory substances are stored in the chitinous exoskeleton.These are also discarded alongwith the exoskeleton during moulting. The nervous system • The nervous system of cockroach is made up of paired ganglia, nervecords and nerves. • In the head brain or supraoesophageal ganglia are located. They are connected with suboesophageal ganglia through circum-oesophageal commissures. • Three pairs of ganglia occur in thorax region and ten pairs of ganglia occur in abdominal region. Nerves arise from ganglia. SENSE ORGANS • Amongst sense organs in cockroach, antennae, eyes, maxillary palps, tarsus of walking legs and anal cerci are included. •Eyes of cockroach are compound. A compound eye is made up of about 2000 ommatidia. It creates a mosaic image and locates any movement quickly • The anal cerci are sensitive to sound. •Antennae, maxillary palp and tarsus are tactile in nature Male reproductive system • Male cockroach possesses one pair of testes. They are located in fourth and fifth abdominal segments • Two vasa efferentia run towards posterior side and open into the ejaculatory duct. Seminal vesicle is associated with the ejaculatory duct. • Ejaculatory duct opens to the outside through the male genital opening. • Male gonapophysis are located in the male genital opening. They play an important role in copulation. • A mushroom gland occcurs in segments 6 & 7 • Another long and flat gland called acessory gland occurs on the ventral side of ejaculatory duct The female reproductve system • Female cockroach possesses one pair of ovaries. They are arranged in segments 4, 5 and 6 on lateral sides. • Ovarian tubules of each line join and form an oviduct. Oviducts from two ovaries join and form uterus. Uterus opens into vagina. • Vagina opens through a vaginal opening to the outside through segment number eight • A pair of branched collateral glands occur as accessory reproductive glands which open in the vaginal duct. • Female gonapophysis occur in the female genital opening.