Morphology of Cockroach MCQ - Practice Questions with Answers

External Morphology of Cockroach: Head and Mouth parts
 

• Cockroaches are brown coloured, nocturnal (more active at night), omnivorous and cursorial (fast runners) insects.
• Cockroaches are found in places of warmth, dampness  and where organic food is available.
• Four common species of cockroaches are Blattella germanica,  Blatta orientalis, Periplaneta americana, Periplaneta australasiae.
• The body of a cockroach is segmented and divisible into head, thorax and abdomen.
• The entire body is covered by chitinous exoskeleton.
• Each segment possesses hardened plates called sclerites.
• Among these, the dorsal ones are called tergites, ventral ones sternite and lateral ones pleuritis. 
• The sclerites are joined together by a thin, soft, flexible articular membrane called arthrodial membrane.

Head

• Head lies anteriorly at a right angle to the longitudinal axis of the body.
• Head is triangular in shape
• Head is formed by the fusion of six segments 
• It is attached to a flexible neck which allows movement in all directions.
• Head bears a pair of thread-like antennae, a pair of compound eyes and a pair of fenestra or photoreceptors.
• Antennae arise from membranous sockets lying in front of eyes. 
• Antennae have sensory receptors that help in monitoring the environment 
• The anterior end of the head bears appendages forming biting and chewing type of mouthparts.

Mouth parts 

• The mouthparts include labrum (upper lip), a pair of mandibles, a pair of maxillae and labium (lower lip). 
• Within the cavity enclosed by the mouthparts, a median flexible lobe is present which acts as tongue (hypopharynx). 
   

 External Morphology of Cockroach: Thorax and Abdomen

Thorax

• The head is connected with thorax by a short extension of prothorax called neck
• It consists of three parts i.e. prothorax, mesothorax and metathorax.
• Each thoracic segment consists of a pair of walking legs.
• From the mesothorax, first pair of wings arises while metathorax gives rise to second pair of wings.
• Forewings are called tegmina and are opaque dark and leathery 
• Hindwings are transparent, membranous and are used in flight.

Abdomen 

• The posterior region of the body is called abdomen and is 10 segment long. 
• In females, the 7th sternum is boat shaped. It together with 8th and 9th segment forms a brood or genital pouch called gynatrium
• The anterior part of genital pouch contains female gonopore, spermathecal pores and collateral glands.
• In males, genital pouch or chamber is present in between 9th and 10th sterna.
• The genital pouch contains dorsal anus, ventral male 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.