Morphology of Cockroach Questions in English

(N/A) $\rightarrow$ The cockroach has two pairs of wings.
$1$. The first pair of wings,known as the forewings or $Tegmina$,arises from the $Mesothorax$. These wings are opaque,dark,and leathery,and they serve to cover and protect the hind wings when the cockroach is at rest.
$2$. The second pair of wings arises from the $Metathorax$. These hind wings are transparent and membranous,and they are primarily used for flight.

(N/A) The ootheca in a cockroach is a dark reddish to blackish brown capsule that contains fertilized eggs.
It is approximately $8 \ mm$ long.
They are dropped or glued to a suitable surface,usually in a crack or crevice of high relative humidity near a food source.
On average,each female produces $9-10$ oothecae,and each ootheca contains $14-16$ eggs.

(N/A) $1$. Many species of cockroaches are wild and have no economic importance,but a few species thrive in and around human habitats.
$2$. They are considered pests because they destroy food and contaminate it with their smelly excreta.
$3$. They act as vectors for various diseases by carrying pathogens on their bodies and contaminating food and water,which can transmit bacterial diseases to humans.

(N/A) $ \Rightarrow $ The eye of a cockroach is situated at the dorsal surface of the head in the form of black, kidney-shaped patches. It is a compound eye. Each eye consists of about $ 2000 $ hexagonal ommatidia.
$ \Rightarrow $ Each compound eye possesses a dioptric region and a receptor region. It is able to form different images of whatever it sees.
$ \Rightarrow $ Hence, a cockroach can receive several images of an object. This kind of vision is known as mosaic vision. From the inner end of each compound eye, thin nerve fibres emerge. They all unite to form the optic nerve, which connects to the brain.
$ \Rightarrow $ In arthropods, the compound eye is the primary visual organ. Its structural unit is the ommatidium. Each ommatidium consists of a corneal lens, crystalline cone, iris pigment cells, receptor cells (retinula cells), and a rhabdom, all supported by a basement membrane. These units work together to provide a wide field of view and high sensitivity to motion.

(N/A) The mouthparts of a cockroach are of the biting and chewing type. They consist of the following structures:
$1$. $A$ labrum (upper lip).
$2$. $A$ pair of mandibles.
$3$. $A$ pair of maxillae.
$4$. $A$ labium (lower lip).
Additionally,a median flexible lobe,known as the hypopharynx,acts as a tongue and lies within the cavity enclosed by the mouthparts.

(N/A) $\Rightarrow$ On an average,females produce $9-10$ oothecae,each containing $14-16$ eggs.
$\Rightarrow$ The development of $P. \text{ americana}$ is paurometabolous,meaning development occurs through nymphal stages.
$\Rightarrow$ The nymph looks very much like the adult. The nymph grows by moulting about $13$ times to reach the adult form.
$\Rightarrow$ The next-to-last nymphal stage has wing pads,but only adult cockroaches have fully developed wings.

(D) Periplaneta americana is a nocturnal organism that prefers to live in damp and dark places.
Regarding other options:
- Cockroaches have $13$ chambers in their heart,not $6$.
- The thorax consists of only $3$ segments (prothorax,mesothorax,and metathorax),not $10$.
- Anal styles are present only in males,whereas anal cerci are present in both sexes.

(B) The cockroach has three thoracic segments: prothorax,mesothorax,and metathorax. The forewings (tegmina) are attached to the mesothorax (the $2^{nd}$ thoracic segment),not the prothorax (the $1^{st}$ thoracic segment). Therefore,the statement in option $B$ is incorrect.

(A) Complete metamorphosis (holometabolous development) involves four distinct stages: egg,larva,pupa,and adult. Both house-flies and mosquitoes undergo this type of development. In contrast,cockroaches exhibit incomplete metamorphosis (paurometabolous development),which involves three stages: egg,nymph,and adult.

(D) The leg of a cockroach consists of five segments.
Starting from the base (proximal end) to the tip (distal end),the correct sequence of these segments is:
$1$. $Coxa$ (the basal segment attached to the thorax)
$2$. $Trochanter$ (a small segment)
$3$. $Femur$ (the largest and thickest segment)
$4$. $Tibia$ (a long,slender segment)
$5$. $Tarsus$ (the terminal part,consisting of tarsomeres)
Therefore,the correct sequence is $Coxa$,$Trochanter$,$Femur$,$Tibia$,and $Tarsus$.

(C) The head of the cockroach is triangular in shape and lies anteriorly at right angles to the longitudinal body axis.
It is formed by the fusion of $6$ segments.
The neck is a short extension of the prothorax,which is flexible and facilitates a wide range of movement in all directions.

(B) The development of a cockroach is paurometabolous,meaning that its development occurs through a nymphal stage. The nymphs resemble adults closely. The nymph grows by moulting approximately $13$ times to reach the adult form. The last nymphal stage possesses wing pads,whereas adult cockroaches possess fully developed wings (forewings and hind wings).

(A) In the given diagram of the posterior part of a male cockroach:
$A$ represents the $9$th sternum.
$B$ represents the anal cercus (jointed filamentous structure).
$C$ represents the $10$th tergum.
$D$ represents the anal style (short,thread-like structure present only in males).
Therefore,the correct labelling is $A - 9$th sternum,$B$ - Anal cercus,$C - 10$th tergum,$D$ - Anal style.

(C) Based on the morphological structure of the cockroach:
$A$ represents the Pronotum,which is the dorsal sclerite of the prothorax.
$B$ represents the Mesothorax,the middle segment of the thorax.
$C$ represents the Metathorax,the posterior segment of the thorax.
$D$ represents the Tegmina (forewings),which are opaque,dark,and leathery.
$E$ represents the Anal cerci,which are paired,jointed,filamentous structures present in both male and female cockroaches.
Therefore,the correct labeling is $A$- Pronotum,$B$-Mesothorax,$C$-Metathorax,$D$-Tegmina,$E$-Anal cerci.

(B) Based on the anatomical structure of the cockroach mouthparts shown in the figure:
$A$ represents the Labium (lower lip).
$B$ represents the Maxilla.
$C$ represents the Labrum (upper lip).
$D$ represents the Mandible.
Therefore,the correct sequence is $A$-Labium,$B$-Maxilla,$C$-Labrum,$D$-Mandible.

(B) Cockroaches are brown or black-bodied animals.
They belong to the kingdom $Animalia$,phylum $Arthropoda$,class $Insecta$,and order $Blattaria$.
Therefore,the correct classification is class $Insecta$ and phylum $Arthropoda$.

(A) Cockroaches possess biting and cutting type of mouth parts,which are adapted for feeding on a variety of organic matter.
Mosquitoes have piercing and sucking type of mouth parts.
Houseflies possess sponging type of mouth parts,while butterflies have siphoning type of mouth parts.

(C) In cockroaches,both males and females possess a pair of jointed,filamentous structures called anal cerci on the $10$th abdominal segment.
However,males possess an additional pair of short,thread-like structures called anal styles,which are absent in females.
Therefore,in males,both anal cerci and anal styles are present.

(D) Anal style is a pair of short,thread-like structures present in males only. In both sexes,the $10$th segment bears a pair of jointed filamentous structures called anal cerci.
There are about $100-150$ malpighian tubules in each cockroach,not $16$.
The nervous system is present ventrally,not dorsally.
Grinding of food is carried out by the gizzard (proventriculus),not just the mouth parts.

(C) Statement $(i)$ is correct: The body of the cockroach is segmented and divisible into head,thorax,and abdomen.
Statement $(ii)$ is incorrect: Cockroaches have an open type of blood vascular system.
Statement $(iii)$ is incorrect: Cockroaches are dioecious (unisexual),meaning male and female reproductive organs are in separate individuals.
Statement $(iv)$ is correct: The development of $P. americana$ is paurometabolous,which means development occurs through nymphal stages that resemble the adult.

(D) $(i)$ Cockroaches are indeed brown or black-bodied animals belonging to the class $Insecta$ of the phylum $Arthropoda$. This statement is correct.
$(ii)$ Males possess a pair of short,thread-like anal styles,which are absent in females. This statement is correct.
$(iii)$ The heart of a cockroach is an elongated muscular tube that lies along the mid-dorsal line of the thorax and abdomen. This statement is correct.
$(iv)$ The nymph of the cockroach ($Periplaneta$ $americana$) undergoes moulting approximately $13$ times to reach the adult stage. This statement is correct.
Since all statements $(i), (ii), (iii),$ and $(iv)$ are correct,the correct option is $D$.

(C) The mouthparts of a cockroach consist of a labrum (upper lip),a pair of mandibles,a pair of maxillae,and a labium (lower lip).
The pre-oral cavity is the space enclosed by these mouthparts.
The mandibles and the $1^{\text{st}}$ maxillae are located on the lateral sides of the pre-oral cavity,helping in the mastication and manipulation of food.

(A) The correct answer is $A$.
In cockroaches,a ring of $6-8$ blind tubules called hepatic or gastric caeca is present at the junction of the foregut and midgut,not the midgut and hindgut.
Option $B$ is correct: The hypopharynx acts as a tongue and lies within the cavity enclosed by the mouthparts.
Option $C$ is correct: In female cockroaches,the $7^{\text{th}}$ sternum is boat-shaped and together with the $8^{\text{th}}$ and $9^{\text{th}}$ sterna forms a brood or genital pouch.
Option $D$ is correct: The $10^{\text{th}}$ abdominal segment in both male and female cockroaches bears a pair of jointed filamentous structures called anal cerci.

(A) In cockroaches,the thorax consists of three segments: $Prothorax$,$Mesothorax$,and $Metathorax$.
Each thoracic segment bears a pair of walking legs.
The cockroach has two pairs of wings.
The first pair of wings,known as $Tegmina$ or forewings,arises from the $Mesothorax$.
The second pair of wings,known as hindwings,arises from the $Metathorax$.
Therefore,the correct option is $A$.

(A) The body of a cockroach is segmented and divisible into three distinct regions: the head,thorax,and abdomen.
$1$. The head is formed by the fusion of $6$ segments.
$2$. The thorax consists of $3$ segments: prothorax,mesothorax,and metathorax.
$3$. The abdomen in both male and female cockroaches consists of $10$ segments.
Therefore,$P = 6$,$Q = 3$,and $R = 10$.

(A) The thorax of a cockroach consists of three parts: prothorax,mesothorax,and metathorax.
In the provided diagram:
- $P$ represents the prothorax,which is the first segment of the thorax.
- $Q$ represents the mesothorax.
- $R$ represents the tegmina (forewing).
- $S$ represents the abdomen.
Therefore,the correct option is $A$.

(A) The mouthparts of a cockroach consist of the following structures:
$P$ represents the Labrum (upper lip).
$Q$ represents the Mandible (jaws).
$R$ represents the Maxilla (first maxilla).
$S$ represents the Labium (lower lip).
Therefore,the correct sequence is $P$: Labrum,$Q$: Mandible,$R$: Maxilla,$S$: Labium.

(D) In female cockroaches,the genital pouch or brood pouch is formed by the $7^{th}$,$8^{th}$,and $9^{th}$ abdominal sterna. However,in terms of the structural boundaries described in the $NCERT$ textbook,the genital pouch is bounded dorsally by the $9^{th}$ and $10^{th}$ terga and ventrally by the $9^{th}$ sternum. This pouch contains the female gonopore,spermathecal pores,and collateral glands.

(A) In cockroaches,there are two pairs of wings.
$1$. The first pair of wings arises from the mesothorax and is called the forewings or $Tegmina$.
$2$. The second pair of wings arises from the metathorax and is called the hind wings.
$3$. The forewings $(Tegmina)$ are opaque,dark,and leathery,and they cover the hind wings when at rest.
$4$. The hind wings are transparent,membranous,and used for flight.
Therefore,the statement that mesothoracic wings are called hind wings is incorrect.

(B) The mouthparts of a cockroach consist of a labrum (upper lip),a pair of mandibles,a pair of maxillae,a labium (lower lip),and a hypopharynx (tongue).
In the provided diagram of the cockroach head:
- $P$ represents the labrum.
- $Q$ represents the hypopharynx (the median lobe acting as a tongue).
- $R$ represents the maxilla.
- $S$ represents the labium.
Therefore,the hypopharynx is represented by $Q$.

(D) कॉकरोच में सिर के पृष्ठीय भाग पर एक जोड़ी संयुक्त आँखें स्थित होती हैं।
प्रत्येक संयुक्त आँख लगभग $2000$ षट्कोणीय ओमेटिडिया (ommatidia) से बनी होती है।
कई ओमेटिडिया की मदद से कॉकरोच एक ही वस्तु की कई छवियां प्राप्त करता है,जिसे मोज़ेक दृष्टि (mosaic vision) कहा जाता है।
इस प्रकार की दृष्टि में संवेदनशीलता अधिक होती है लेकिन रिज़ॉल्यूशन कम होता है,जो रात के समय देखने के लिए अनुकूलित है।
अतः,दिए गए सभी विकल्प सही हैं।

(B) In cockroaches,the female produces egg cases called oothecae.
Each ootheca is a dark reddish to blackish brown capsule,about $8-10 \ mm$ long.
They are dropped or glued to a suitable surface,usually in a high humidity area near a food source.
On average,each ootheca contains $14-16$ eggs.

(C) The development of the cockroach is paurometabolous,meaning there is development through the nymphal stage.
The nymphs look very much like adults.
The nymph grows by moulting (ecdysis).
The nymphal stage undergoes moulting approximately $13$ times to reach the adult form.
Therefore,the correct option is $C$.

(A) In male cockroaches,the male genital pore is surrounded by a number of chitinous asymmetrical structures called gonapophyses or phallomeres. These structures are involved in copulation and are located ventrally to the anus.

(C) Cockroaches are unisexual organisms,meaning they have separate male and female individuals.
In biological terms,organisms with separate sexes are called dioecious.
Monoecious and hermaphrodite are terms used for organisms that possess both male and female reproductive organs in the same individual (bisexual).
Therefore,the cockroach is dioecious.

(C) Option $C$ is the correct answer because anal styles are present only in male cockroaches and are absent in female cockroaches.
Options $A$,$B$,and $D$ are incorrect because anal cerci,dark brown body colour,and sclerites are common features found in both male and female cockroaches.

(A) The correct answer is option $(A)$.
In both male and female cockroaches,the $10^{\text{th}}$ abdominal segment bears a pair of jointed filamentous structures known as anal cerci.
These structures are sensory in nature and help the cockroach in detecting vibrations in the environment.
Options $(B)$,$(C)$,and $(D)$ are incorrect because the $5^{\text{th}}$,$8^{\text{th}}$,and $9^{\text{th}}$ segments do not possess anal cerci,and the $11^{\text{th}}$ abdominal segment is absent in adult cockroaches.

(A) In cockroaches,the exoskeleton consists of hardened plates called sclerites.
These sclerites are joined to each other by a thin and flexible membrane known as the arthroidal membrane or articular membrane.
This membrane allows for the movement of the body segments and appendages,as it provides flexibility between the rigid sclerites.

(D) In $Periplaneta$ $americana$ (cockroach),the female produces $9-10$ oothecae during its reproductive life.
Each ootheca is a dark reddish to blackish brown capsule,about $8 \ mm$ long,and contains $14-16$ eggs.
Therefore,the correct sequence to fill the blanks is $9-10$ and $14-16$.

(B) In female cockroaches,the $7^{\text{th}}$ sternum is boat-shaped.
It,together with the $8^{\text{th}}$ and $9^{\text{th}}$ sterna,forms a brood or genital pouch.
The anterior part of this pouch contains the female gonopore,spermathecal pores,and collateral glands.

(C) In the female cockroach,the $7^{th}$ sternum is boat-shaped.
Together with the $8^{th}$ and $9^{th}$ sterna,it forms a brood or genital pouch,which contains the female gonopore,spermathecal pores,and collateral glands.

(C) The mouthparts of a cockroach consist of a labrum,a pair of mandibles,a pair of maxillae,a labium,and a hypopharynx.
Each mandible is heavily sclerotized and possesses teeth-like structures used for both incising (cutting) and grinding (crushing) the food.
If the mandibles are removed,the cockroach will lose the ability to perform both of these essential mechanical processes.
Therefore,the correct answer is $C$ (Both).

(A) In the mouthparts of a cockroach,the $Labrum$ is a single,plate-like structure that functions as the upper lip. It is attached to the clypeus and covers the mouth cavity from the front. Therefore,the correct answer is $A$.

(B) The correct answer is $B$. Cockroaches are omnivorous,not herbivorous. They feed on a wide variety of organic matter,including decaying plant and animal material,food scraps,and even paper or glue. They are nocturnal,meaning they are active at night,and they are indeed serious pests and vectors of several diseases. They belong to the class $Insecta$ under the phylum $Arthropoda$,and $Periplaneta$ $americana$ is the most common species found in homes.

(C) In cockroaches, the respiratory system consists of a network of trachea that open through $10$ pairs of small holes called spiracles present on the lateral side of the body.
Out of these $10$ pairs, $2$ pairs are located in the thoracic region and $8$ pairs are located in the abdominal region.
Therefore, the correct answer is $10$ pairs.