● Cockroaches are brown or black bodied animals that are included in `color{Brown}"class Insecta"` of `color{violet}"Phylum Arthropoda"`.

● `color{violet}"Bright yellow, red and green"` coloured cockroaches have also been reported in `color{violet}"tropical regions"`.

● Their size ranges from `color{violet}"¼ inches to 3 inches"` (0.6-7.6 cm) and have long `color{violet}"antenna, legs"` and `color{violet}"flat extension"` of the upper body wall that conceals head.

● They are `color{violet}"nocturnal omnivores"` that live in `color{violet}"damp places"` throughout the world.

● They have become `color{violet}"residents of human homes"` and thus are serious `color{violet}"pests and vectors"` of several diseases.

● The `color{violet}"adults"` of the common species of cockroach, `color{Brown}"Periplaneta Americana"` are about `color{violet}"34-53 mm long"` with wings that extend beyond the `color{violet}"tip of the abdomen"` in males.

● The body of the cockroach is segmented and divisible into three distinct regions – `color{Brown}"head, thorax and abdomen"`.

● The entire body is covered by a `color{violet}"hard chitinous exoskeleton"` (brown in colour).

● In each segment, exoskeleton has hardened plates called `color{Brown}"sclerites"` (`color{violet}"tergites dorsally"` and `color{violet}"sternites ventrally"`) that are joined to each other by a `color{violet}"thin and flexible"` articular membrane (`color{Brown}"arthrodial membrane"`).

● `color{violet}"Head is triangular"` in shape and lies anteriorly at `color{violet}"right angles"` to the longitudinal body axis.

● It is formed by the `color{violet}"fusion of six segments"` and shows `color{violet}"great mobility"` in all directions due to flexible neck.

● The head capsule bears a `color{Brown}"pair of compound eyes"`.

● A pair of `color{Brown}"thread like antennae"` arise from `color{violet}"membranous sockets"` lying in front of eyes.

● Antennae have `color{violet}"sensory receptors"` that help in monitoring the environment.

● Anterior end of the head bears appendages forming `color{Brown}"biting and chewing"` type of `color{violet}"mouth parts"`.

● The mouthparts consisting of a `color{violet}"labrum (upper lip"`), a `color{violet}"pair of mandibles"`, a `color{violet}"pair of maxillae"` and a `color{violet}"labium (lower lip)"`.

● A median `color{violet}"flexible lobe"`, acting as `color{Brown}"tongue (hypopharynx)"`, lies within the cavity enclosed by the mouthparts.

● Thorax consists of three parts – `color{Brown}"prothorax, mesothorax"` and `color{violet}"metathorax"`.

● The head is connected with thorax by a `color{violet}"short extension"` of the prothorax known as the `color{Brown}"neck"`.

● Each thoracic segment bears a pair of `color{violet}"walking legs"`.

● The `color{violet}"first pair of wings"` arises from mesothorax and the `color{violet}"second pair"` from metathorax.

● `color{violet}"Forewings (mesothoracic)"` called `color{Brown}"tegmina"` are opaque `color{violet}"dark and leathery"` and cover the hind wings when at rest.

● The `color{violet}"hind wings"` are `color{violet}"transparent, membranous"` and are used in flight.

● The `color{violet}"abdomen"` in both males and females consists of `color{violet}"10 segments"`.

● In females, the `color{violet}"7th sternum"` is boat shaped and together with the `color{violet}"8th and 9th sterna"` forms a `color{Brown}"brood or genital pouch"` whose anterior part contains `color{violet}"female gonopore"`, `color{violet}"spermathecal pores"` and `color{violet}"collateral glands"`.

● In males, `color{Brown}"genital pouch or chamber"` lies at the `color{violet}"hind end of abdomen"` bounded dorsally by 9th and 10th terga and ventrally by the 9th sternum.

● It contains `color{violet}"dorsal anus"`, ventral `color{violet}"male genital pore"` and `color{violet}"gonapophysis"`.

● Males bear a pair of `color{Brown}"short, threadlike anal styles"` which are absent in females.

● In both sexes, the `color{violet}"10th segment"` bears a pair of `color{violet}"jointed filamentous structures"` called `color{Brown}"anal cerci"`.