Cockroach show characteristic features in segmentation, symmentry and body organization. Its
scientific name is Periplaneta americana.
Morphology – Body is covered with hard chitinous exoskeleton. Size about 25 to 45 mm long cm
and 8 to 12 broad found all over the world colour varies. Body is divisible into three regions. Head,
thorax, abdomen. Each having segmented appedages to perform various functions.
Anatomy : (Internal structure) Body wall cockroach has three layers. Digestive system complete
- hepatic cacae and malpighian tubules present figure blood vascular system. Open type – Heart has 13
units with valved ostia. Haemocoel has two types of cells. Respiratory system is made up of network
of branched tracheal tubes through out the body. Terminal branches are called tracheols. Ten pairs of
spiracles formed and protected by chitinous bristles. Excretory system has malpighian tubules is
haemolymph. Urecotelic animal. Nervous system is made up of paired ganglia, nerve cords and nerves.
Nerve-ring is present sense organs are antenae, eyes, maxillary palps, tarsus of walking legs and anal
circus. Reproductive system unisexual male slightly bigger. Internal fertilization 14-16 eggs are fertilized
in Ootheca vlymphal stage, youngones look alike parents develop into adult by under going ecdytis