This ppt deals with brief description of Cockroach (Periplaneta americana) including morphology, anatomy, physiology, etc. Useful for NEET, NET, SET, PGT, TGT, TET, PG, UG, other competitive exams including 10+2 All boards. if you have any Question in Biological Sciences you can call or Whatsapp on 9839119920 without any fee or charges just to help needy students.

1. General Description of
Cockroach
(Periplaneta americana)
• By – Dr. Mohit Tiwari

2. The Cockroach
Periplaneta americana
Basic details for NET, SET, NEET, PGT,
TGT, TET, PG, UG, Other exams and
10+2 all boards
By - Dr. Mohit Tiwari

3. Cockroach (Periplaneta americana)

4. Classification-
Kingdom - Animalia
Phylum – Arthropoda
Class – Insecta or Hexapoda
Genus – Periplaneta
Species – americana
Also called as Bombay canary or Ship
cockroach or American cockroach
Other Indian forms of cockroaches are Blatta
orientalis , and Blattella gemranica

5. General characters – found in tropical, subtropical regions,
Lives in damp, cool, dark places, where large quantity of
decomposing organic material is available as food. Nocturnal,
cursorial (speed- 75-125mt/sec)
Six legs, Thick chitinious cuticle as exoskeleton, jointed
appendages, two pair of wings, and one pair of antenna.

6. Body divisible in Head, Thorax and Abdomen.
Head is made up of 6 segments. Thorax of 3 segment (Prothorax,
Mesothorax and Meta thorax). Abdomen of 10 segments, In female only
7 segments are visible, 3 segments are modified to form genital
chamber.
Wings 2 pair dorsal, 1st pair from junction of pro and meso thorax
leathery, Protective in nature called Elytra, 2nd pair true wings soft and
small for flight originate from junction of Meso and Meta thorax.

7. Cockroach is a unisexual animal, sexual dimorphism
present –
1.Male with anal style, anal cerci and 10 segments.
2.Female with boat shape tapering 7th terga and
anal cerci only, no anal style.

8. Head -
• Frontal view of Head
Made of 6 segments-
Clypeus -1
Frons – 1
Epicranial plates - 2
Gena – 2
Head bears -
Compound Eye – 1pair
Ocellar spot – 1pair
Multisegmented
antenna – 1pair in
antennal socket

9. • Posterior view of head
Head is attached
with thorax
posteriorly, through
occipital foramen, by
help of cartilaginous
endoskeleton called
Tentorium.

10. Mouth parts – 5 type
A. Labrum 1 soft plate
as upper lip.
B. Mandible 1 pair
hardest part in
cockroach for cutting
of food.
C. Maxilla 1 pair for
holding the food.
D. Labium – 1 as lower
lip.
E. Hypo pharynx 1 in
between mouth
parts. Functions as
tongue.

11. Legs – 3 pair (6)
Legs found attached with
thorax attached on
ventrolateral side 1 pair from
each segment i.e. From Pro
thorax, Meso thorax & Meta
thorax.
Leg is made up of Coxa
Trochanter, Femur, Tibia,
Tarsus, Pretarsus, Claws and
Aerolium. Tarsus bearing
Plantullae the sensory
structures.
Femur and Tibia bears bristles
like Chitineous structures.

12. Alimentary canal
Salivary gland 1 pair
Oesophagus -> Crop -> Gizzard
With 6 Chitinious teeth for
grinding of food -> 8 hepatic
caeca -> Mesentron with 60-80
Malpighian tubules -> Ileum ->
Colon -> Rectum with 6
longitudinal rectal folds on inner
surface opens out by anus on 10
segment.
Stomodaeum up to gizzard,
Mesodaeum upto colon and
Proctodaeum from rectum to
anus.

13. Anatomy of Stomodaeum or foregut

14. Circulatory system - 13 chambered heart with 1 pair Ostia in each
chamber, large Perivisceral sinus or Haemocoel , dorsal Pericardial
sinus separated by dorsal diaphragm , Ventral Perineural sinus
separated by ventral diaphragm. 13 pair dorsal alary muscles to
help in blood circulation. Blood is called as Haemolymph or
Haemocoelomic fluid, Lymph like watery bluish white in colure.
Haemocynine is a Cu containing blood pigment. Which is not a
respiratory pigment.

15. Excretion – Uricotelic , storage excretion
Excretion by –
1. Malpighian tubules – 60-120, in 6-8 groups,
fine yellow tubules attacached with intestine.
2. Fat bodies – contain urate cells for storage
excretion of Uric acid.
3. Uricose gland – of male reproductive system
passes out uric acid with spermatophore.
4. Cuticle or body wall - helps in excretion as
nitrogenous waste are removed with cuticle
during molting.

16. Respiratory system-
Respiratory system
is made up of tube
like tracheal
system, opens out
on lateral side of
the body by 10
pair of circular
openings called
spiracles

17. Spiracles open in
atrium which bifurates
in dorsal, ventral and
longitudinal branches
of Trachea, which
further divides in fine
tubular structures
called tracheole which
enters in different
organs and tissues
giving direct supply of
air/ oxygen to them.

18. Nervous system
Made up of dorsal brain like
bilobed supra oesophageal
ganglion composed of 3 pair
of ganglions, lateral
circumoesophageal
connectives fuse to form
sub oesophageal ganglion
followed by paired ventral
nerve cord, with 3 ganglion
in thoracic region(Pro, Meso
and Meta) and 6 ganglions
in abdominal region, 6th
abdominal ganglion is
largest.

19. Sense organs –
Tactile – for feeling of touch present on antennae,
maxillary and labial palps etc.
Olfactory – for smell on antenna and palps.
Gustatory - for taste on Palps and mouth parts.
Auditory or chordotonal – for hearing on anal cerci.
Thermoreceptive – for temperature on pulvulli in legs.
Photoreceptors – for light are of two type A- Simple and
B- Compound eyes.
A. Simple eye – one pair frontal, non image forming, for
detection of intensity of light.
B. Compound eye – one pair, bean or kidney shape,
dorso-lateral in position.

20. Compound eye -
Made up of about 2000
ommatidia or Eyelets.
Image is formed in pieces so
called mosaic image.
Vision –
In presence of light - clear
but dull image is formed
called Apposition image.
In dark or dim light – dark
but hazy image is formed
called Superposition image.

21. Structure of
Ommatidia or Eyelet
Outer most
transparent cuticle
followed by Lens,
Corneagen cells,
1 Crystalline cone,
4 Cone cells,
followed by central
Rhabdom,
surrounded with
7 Retinular cells
and Retinal
pigment sheeth.

22. Cockroach is unisexual
or dioecious.
Male Reproductive
System -
Externally - Anal cerci on last
segment.
Internally -
Testes- 1 pair on dorsal side.
Vasdiferens- 1pair
Utricular or mushroom gland-
Made up of – Utriculi majors, utriculi
breviores and seminal vesicles
Ejaculatory duct- 1
Phallic gland- 1
Genital plates- 3 as left phallomere,
right phallomere and ventral
phallomere
Utricular glands and phallic gland
forms Spermatophore filled with
sperms.

23. Female reproductive
system -
Ovary – 1 pair, each ovary
is divided in 8 ovarioles.
Oviduct - 1 pair fused to
form 1 common oviduct.
Spermatheca made up of 2
lobes left large and right
small lobe.
Collateral glands one pair
left is large and right is
small.
Gynovavular plates and 3
pair gonapophysis in
genital chamber.

24. Copulation in night. During copulation spermatophore is
transferred in female genital chamber, Where sperms are
released in spermatheca and empty spermatophore passed out
from body. Sperms from spermatheca are used in fertilization.
Fertilization internal in common oviduct. Fertilized eggs are
passed out in ootheca containing two rows of 8 eggs (8+8 = 16).

25. Otheca is formed by Dihydrxyphenol from right collateral
gland and protein from left collateral resulting formation
of scleroprotein capsule around the fertiliged eggs.
Ootheca is laid by female in dark and dry place.
Metamorphosis – after some time ootheca hatches and
several nymph are released. In about 1 year by help of
prothoracic hormone after 9-11 moulting adult cockroach
is formed. Metamorphsis in cockroach is hemimetabolous
or incomplete.
END