College of Agricultyre,Rewa,(M.P.)
Class- B.Sc.(Hons.) 1st year, Semester-2nd
Course title – Fundamental of Entomology
Lecture note by Alam M A April 2, 2020
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CONTENTS ( 05 Lectures)
1 LEC.6. Body segmentation: Structure of head & its types
2 LEC7. Body segmentation: Structure of thorax and abdomen
3 LEC 8. Structure and modifications of insect antennae
4 LEC 9. Structure, function and modifications of insect mouth parts: biting and
chewing andpiercing and sucking types ( bug type)
5 LEC 10. Structure and modifications of insect legs
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Lecture 6&7
LEC.6. Body segmentation: Structure of head & its types
LEC7. Body segmentation: Structure of thorax and abdomen
Lec 6 Structure of head & its types
Insect body is divided into three separate regions i.e. head, thorax and abdomen
and these region are called tagmata and grouping of body segments into distinct
regions is acknowledged as tagmosis .
, ( source- internet fig.)
I. HEAD ;It is first and anterior part of the body which shows great
variation in shpe and size in insects of different orders . it is formed by
the fusion of six segments namely pre-antennary,antennary, intercalary,
mandibular, maxillary and labial segments. Head is attached or
articulated to the thorax through neck or Cervix. Head capsule is a
sclerotized structure and formed by the fusion of several hard plates
(sclerites) and weak lining called suture.
( source- taken from internet)
, posterior view of insect head capsule
( source-taken from internet)
Sclerites of Head
i. Vertex: it is the top sclerite of the head capsule and situated between
compound eyes.
ii. Frons: It is the facial area below the vertex and above the clypeus.
iii. Clypeus: it is the scleritesituated below the frons and the labrum is attached
to it.
iv. Gena: it is the Lateral cranial area located below the compound eyes.
v. Occiput : the posterior part of the Cranial area is the occiput
vi Post occipital ; it is inverted “u”shapedsclerite situated posterior to occiput .
Sutures of Head:
i. Epicranial suture: it is Inverted `Y' shaped suture located medially on the top of
head . The stem of the suture is known as a median suture /coronal suture while
two branches are called lateral suture /frontal suture. It is the place through
which molting take place.
Class- B.Sc.(Hons.) 1st year, Semester-2nd
Course title – Fundamental of Entomology
Lecture note by Alam M A April 2, 2020
--------------------------------------------------------------------------------------------------------------------
CONTENTS ( 05 Lectures)
1 LEC.6. Body segmentation: Structure of head & its types
2 LEC7. Body segmentation: Structure of thorax and abdomen
3 LEC 8. Structure and modifications of insect antennae
4 LEC 9. Structure, function and modifications of insect mouth parts: biting and
chewing andpiercing and sucking types ( bug type)
5 LEC 10. Structure and modifications of insect legs
---------------------------------------------------------------------------------------------------------------------------------
Lecture 6&7
LEC.6. Body segmentation: Structure of head & its types
LEC7. Body segmentation: Structure of thorax and abdomen
Lec 6 Structure of head & its types
Insect body is divided into three separate regions i.e. head, thorax and abdomen
and these region are called tagmata and grouping of body segments into distinct
regions is acknowledged as tagmosis .
, ( source- internet fig.)
I. HEAD ;It is first and anterior part of the body which shows great
variation in shpe and size in insects of different orders . it is formed by
the fusion of six segments namely pre-antennary,antennary, intercalary,
mandibular, maxillary and labial segments. Head is attached or
articulated to the thorax through neck or Cervix. Head capsule is a
sclerotized structure and formed by the fusion of several hard plates
(sclerites) and weak lining called suture.
( source- taken from internet)
, posterior view of insect head capsule
( source-taken from internet)
Sclerites of Head
i. Vertex: it is the top sclerite of the head capsule and situated between
compound eyes.
ii. Frons: It is the facial area below the vertex and above the clypeus.
iii. Clypeus: it is the scleritesituated below the frons and the labrum is attached
to it.
iv. Gena: it is the Lateral cranial area located below the compound eyes.
v. Occiput : the posterior part of the Cranial area is the occiput
vi Post occipital ; it is inverted “u”shapedsclerite situated posterior to occiput .
Sutures of Head:
i. Epicranial suture: it is Inverted `Y' shaped suture located medially on the top of
head . The stem of the suture is known as a median suture /coronal suture while
two branches are called lateral suture /frontal suture. It is the place through
which molting take place.
