MORPHOLOGY

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 MORPHOLOGY:

  The adult of common species of cockroach, Periplaneta Americana are about 34-53 mm long with wings that extend beyond the tip of the abdomen in males. The body of the cockroach is segmented and divisible into three distinct regions - head, thorax and abdomen. The entire body is covered by a hard chitinous exoskeleton (which is brown in colour). In each segment, exoskeleton has hardened plates called sclerites (tergites dorsally and sternites ventrally) that are joined to each other by a thin and flexible articular membrane (arthrodial membrane). 

EXTERNAL FEATURES OF COCKROACH


Head is a triangular shape and lies anteriorly at right angles to the longitudinal body axis. It is formed by the fusion of six segments and show great mobility in all directions due to flexible neck. The head capsule bears a pair of compound eyes. A pair of thread like antennae arise from membranous socket lying in front of eyes. Antennae have sensory receptors that helps in monitoring the environment. Antennae end of the head bears appendages forming biting and chewing type of mouth parts. The mouth parts consisting of a labrum (upper lip), a pair of mandibles, a pair of maxillae and a labium (lower lip). A median flexible lobe, acting as tongue (hypopharynx), lies within in the cavity enclosed by the mouth parts. Thorax consists of three parts - prothorax, mesothorax and metathorax. The head is connected with thorax by a short extension of the prothorax know as neck. Each thoracic segment bears a pair of walking legs. The first pair of wings arises from mesothorax and the second pair from metathorax. Forewings (mesothoracic) called tegmina are opaque dark and leathery and cover the hind wings when at rest. The hind wings are transparent, membranous and used in flight.

       The abdomen in both males and females consists of 10 segments. In females, the 7th sternum is boat shaped and together with the 8th and 9th sterna forms a brood or genital pouch whose anterior part contains female gonopore, spermathecal pores and collateral glands. In males, genital pouch or chamber lies at the hind end of abdomen bounded dorsally by 9th and 10th terga and ventrally by the 9th sternum. It consists dorsal anus, ventral make genital pore and gonapophysis. Males bear a pair of short, thread like anal styles which are absent in females. In both sexes, the 10th segment bears a pair of jointed filamentous structures called anal cerci.

      HEAD REGION OF COCKROACH:-

PARTS OF HEAD REGION


PARTS OF MOUTH REGION


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