characters of 30 insect orders

1. welcome

2. INSECT ORDERS
Presented to:
Dr. R S Meena presented by:
Kotresh S
17412EAZ005

3.  Insect is a six legged arthropod. Taxonomist A.D.
Imms proposed a classification of insect.
 Phylum : Arthropoda (with several classes)
 Class: Insecta (Hexapoda)

4. CHARACTERS OF CLASS INSECTA
1. Body is divided into three regions
2. In head a pair of antenna and a pair of compound eyes are
usually present.
3. Thorax is the centre of locomotion with, 3 pairs of five jointed
legs and two pairs of wings.
4. Excretion is mainly through malpighian tubules.
5. Tracheal system of respiration well developed.
6. Brain is divided into protocerebrum, deutocerebrum and
tritocerebrum.

5.  The class Insecta has two subclasses viz., Apterygota
and Pterygota.
Apterygota Pterygota
1. Primarily wingless evolved from
wingless
ancestors
Winged or secondarily wingless- evolved
from winged ancestors. e.g. Flea,
headlouse, bed bug.
2. Metamorphosis is totally absent or
slight.
Present.
3. Mandibular articulation in head is
monocondylic i.e., single
Dicondylic i.e., double.
4. Pleural sulcus in thorax is absent. Present.
5. Pregenital abdominal appendages
Present.
Absent

6. The subclass Apterygota has 4 orders namely
1. Thysanura - Silverfish (Thysan-fringed, Ura-tail)
2. Collembola- Springtail or snowflea (coll-glue; embol-
peg)
3. Protura - Proturans or Telsontail (Pro-first, Ura-tail)
4. Diplura - Diplurans or Japygids (Di-two; Ura-tail)

7. PROTURA
 Protos=first; uros=tail
 Ex. Telson-tails, Acerantomon
 This order includes 90 species.
 They are minute insects with somewhat depressed, soft white
bodies, with prognathous head and without eyes.
 Antennae are also absent.
 They are primitively wingless, with reduced prothorax.
 Tarsus is one-segmented.
 Abdomen is 11-segmented, with telson (that is why called telson-
tails) but without cerci.
 Fore legs have sensory function.
 Telson-tails have worldwide distribution. They are found in damp
and dark places, in decaying matter, in debris, under bark, stones
or in leaf-litter and are photophobous.

9. DIPLURA
 Diplos=double; uros=tail
 Ex. Campodea and Japyx
 They are herbivores or predaceous, found in damp, dark
situations among dry leaves, dead wood or under stones where
they feed on fungus or other matters.
 This is a small group having about 400 species worldwide.
 They have prognathous head without compound eyes or ocelli
and with long moniliform antennae.
 Mouthparts are mandibulate type.
 They are primitively wingless.
 Tarsi one or two segmented.
 Cerci are two long moniliform as in campodeids or short pincer-
like as in japygids. Size 1-2 mm.

11. COLLEMBOLA
 Colla=glue; embolon=peg
 Ex. – Springtails and snow fleas
 Minute, soft bodied insects, 2 mm long, dull whitish in colour.
 Head prognathous. Compound eyes with 8 facets. Ocelli absent.
 Antennae 4-6 segmented, filiform. Maxilla and labium reduced.
 One-segmented tarsus is fused with tibia.
 Abdomen 6-segmented with a telson, which is modified to form a springing
organ.
 ventral tube ("collophore") on segment 1 of abdomen (adhesive in some
groups, but primarily involved with excretion and water transport)
 springing mechanism formed from retinaculum on segment 3, furcula on
segment 4
 It can jump about 3 inches high with the help of furcula. Cerci never present.
 Their food consists of decaying matter in damp soil. They are found in
decaying matter, in damp places, in debris

13. THYSANURA
 Thysanos=bristle; uros=tail
 Ex. – Bristle-tails; silverfish, Lepisma
 The order includes about 350 species.
 Insects have soft elongated bodies covered with silvery scales.
Prognathous head with compound eyes and with or without ocelli.
 Antennae long, multisegmented, filiform.
 Mouthparts biting and chewing type.
 Tarsi 2-4 segmented. Cerci long and multisegmented, filiform,
usually three.
 They are primitively wingless insects.
 They are found in a variety of habitats, usually in damp and dark
places. Silverfish are found on the walls in houses, behind the
pictures and books. They are omnivorous and prefer starchy
material. Many are found in debris

15.  the sub-class pterygota has two division, namely exopterygota
and endopterygota based on the wing development.
Character Exopterygota Endopterygota
1. Wing
development
External Internal
2. Type of
metamorphos
is
Incomplete(Hemimetabola) or
gradual (Pau- rametabola)
Complete (Holome- tabola)
3. Pupal stage Absent Present
4. Immature
stage
Naiad or Nymph Larva
5. No. of orders 16 9

16. EXOPTERYGOTA
01. Ephemeroptera - Mayflies
02. Odonata-Dragonfly, Damselfly
Group I. Paleopteran
orders (1,2)
03.Plecoptera - Stonefly
04. Grlloblatodia - Rock crawlers
05. Orthoptera-Grasshopper, locust,
cricket, mole cricket
06. Phasmida-stick insect, leaf insect
07. Dermaptera-Earwigs
08. Embioptera-Webspinners/Embids
09. Dictyoptera-cockroach, preying mantis
10. Isoptera - Termites
11. Zoraptera - Zorapterans
Group II. Orthopteroid
orders(3-11)

17. 12. Psocoptera - Book lice
13. Mallophaga - Bird lice
14. Siphonculata - Head and body louse
15. Hemiptera - Bugs
16. Thysanoptera - Thrips
Group III. Hemipteroid
orders(12-16)

18. ENDOPTERYGOTA
01. Neuroptera-Antilions, aphidlion, owl flies, mantispid
flies.
02. Mecoptera - Scorpionflies.x
03. Lepidoptera - Butterflies and moths.
04. Trichoptera - Caddisfly.
05. Diptera - True fly.
06. Siphonaptera - Fleas.
07. Hymenoptera - Bees, wasps, ants.
08. Coleoptera - Beetles and weevils.
09. Strepsiptera - Stylopids.
Group IV. Panorpoid
complex (1-6)

19. EPHEMEROPTERA
 Ephemeral=short-lived
 Ex. – Mayflies, Dayflies and Shadflies
 They are small, light-coloured, soft-bodies, light greenish or
yellowish insects.
 Head is prognathous and compound eyes well-developed.
Ocelli three. Short, setiform antennae.
 Mouthparts biting and chewing type by vestigial.
 Weak clinging type of legs, with 5-jointed tarsi.
 Tip of abdomen with two or three long cerci.
 Larvae are aquatic and called “Naiad”, having abdominal gills,
chewing mouthparts. Larvae are mostly herbivorous but
sometimes carnivorous also.
 Adults are found in swarms, particularly in the morning and
evening, near water bodies

21. ODONATA
 Odonus=toothed
 Ex.Dragonflies and damselflies
 Medium to large sized insects
 They are attractively coloured
 Head is globular and constricted behind into a petiolate neck.
 Compound eyes are large.
 Three ocelli are present
 Mouthparts are adapted for biting. Mandibles are strongly toothed
Lacinia and galea are fused to form mala which is also toothed.
 Wings are either equal or sub equal, membraneous; venation is
net work like with many cross veins. Wings have a dark
pterostigma towards the costal apex. Sub costa ends in nodus.
Wing flexing mechanism is absent.

22.  Legs are anteroventrally placed. They are suited for
grasping, holding and conveying the prey to the mouth.
Spinose femora and tibiae are useful for holding the prey.
Forward shift of leg attachments allow easy transfer of prey
items to mouth in flight. Legs are held in such a way that a
basket is formed into which the food is scooped.
 Abdomen is long and slender. In male gonopore is present
on ninth abdominal segment. But the functional copulatory
organ is present on the second abdominal sternite. Before
mating sperms are transferred to the functional penis.
Cercus is one segmented.
 Metamorphosis is incomplete with three life stages. The
naiad is aquatic. Labium is greatly elongated, jointed and
bears two hooks at apex. It is called mask. It is useful to
capture the.

23.  Dragonflies have stout bodies, large eyes, which
almost touch each other; bases of wings are broader
than the apical part; wings are held horizontally while at
rest. They are strong fliers and catch their prey in flight.
Normally fly high in the open air.
 Damselflies possess slender bodies and small head;
their eyes are smaller and widely separated from each
other. Wings are narrower at the base and broader
towards the apex; venation net-like. They usually spend
time under the canopy of the plants, are not very strong
flier and hunt small insects that are feeding on the
plants.

24. Dragon fly
Damsel fly

26. PLECOPTERA
 plekein=to fold; pteron=wing
 Ex. Stoneflies; Salmon flies
 They are medium to large insects, having about 1500 species.
 Head is prognathous, with small to moderate compound eyes. Ocelli
present or absent. Antennae long, either filiform or setaceous.
Mouthparts are mandibulate but weak.
 Wings are transparent, the hind wing a little broader, while resting
they are folded over the abdomen.
 Tarsi 2-3 segmented.
 Tip of abdomen with two long filiform cerci but without an ovipositor.
Males can produce drumming sound with a disc-like percussion on
9th abdominal segment.
 Adults are herbivorous or predaceous found resting on vegetation by
the side of water sources.
 Nymphs are aquatic, predaceous, found in the rapidly flowing
streams.

28. GRYLLOBLATTODEA
 Ex. Grylloblatta
 Only six species, which show primitive features, are known from
North America, Russia and Japan.
 The insects are found beneath stones, up to an altitude of 6,000
feet.
 They are related to Orthoptera from which they must have
separated very early in evolution.
 They are wingless insects, without eyes and ocelli but sometimes
reduced eyes are present.
 Antennae are long and filiform and mouthparts mandibulate.
 All legs are similar and for slow-walking with 5-segmented tarsi.
There is one pair of long, 8-segmented, filiform cerci.
 Female possesses long ovipositor. Head is prognathous and
body dorsoventrally flattened.

30. ORTHOPTERA
 Synonyms: Saltatoria, Saltatoptera
 Etymology: Ortno - straight; ptera-wings.
 Common names: Grasshoppers, Locust, Katydid,
Cricket, Mole cricket
 Characters
 They are medium to large sized insects.
 Antenna is filiform.
 Mouthparts are mandibulate.
 Prothorax is large. Pronotum is curved, ventrally covering
the pleural region.
 Hindlegs are saltatorial
 Forewings are leathery, thickened and known as tegmina.

31.  They are capable of bending without breaking.
 Hindwings are membranous with large anal area. They
are folded by longitudinal pleats between veins and kept
beneath the tegmina.
 Cerci are short and unsegmented.
 Ovipositor is well developed in female.
 Metamorphosis is gradual. In many Orthopterans the
newly hatched frist instar nymphs are covered by loose
cuticle and are called pronymphs. Wing pads of nymphs
undergo reversal during development.
 Specialized stridulatory (sound-producing) and auditory
(hearing) organs are present.

33. PHASMIDA
 Phasmidus=ghost or spectre
 Ex.Leaf insects and stick insects
 They are cryptically coloured, brown or green phytophagous insects.
 Fore wings are leathery while hind wings membranous.
 Mouthparts are biting and chewing type.
 All legs are similar with small coxae and used for slow walking on plants.
 Head having long filiform antennae and small compound eyes. Male genitalia
and ovipositor concealed.
 Leaf insects are superb mimics of the broad-leaved plants.
 Their wings are flattened, green and venation mimicking leaf-venation. Legs
also got flattened leaf-like.
 They are impossible to locate on the plants as the entire body is perfectly
camouflaged. Their movements are slow.
 Stick insects mimic grasses. Their bodies are elongated like strands of grass.
Legs and antennae are thin and long. They feed on grasses perfectly
camouflaged and sometimes sway as if in breeze.

35. DERMAPTERA
 derma=skin; pteron=wing
 Ex. Earwigs
 This order contains 1100 species.
 The insects have narrow, elongated bodies with prognathous head and generally dark
coloration.
 They have prognathous head, with well-developed compound eyes (sometimes absent).
Ocelli absent. Antennae are long and filiform and mouthparts strong mandibulate.
 Forewings are reduced to short leathery tegmina under which large membranous, fan-like
hind wings are kept folded like handkerchief. Before flying they take considerable time to
unfold the hind wings with the help of forceps.
 Legs strong for walking and tarsi are 3-segmented.
 Abdomen is 11-segmented, at the tip of which cerci are modified in the form of forceps,
which are used for defense. Ovipositor is reduced.
 They are nocturnal and prefer moist dark places, sometimes attracted to light in the night.
They are predaceous in tropics and herbivores in temperate areas.

37. EMBIOPTERA
 embios=lively
 Ex. Web-spinners
 They are small slender-bodied insects, with a large prognathous
head.
 Compound eyes are large in male but smaller in female. Ocelli are
absent.
 Antennae are filiform and mouth parts mandibulate.
 Females are wingless and males winged, with membranous,
transparent or sometimes cloudy equal-sized wings.
 Legs short, adapted for crawling. Fore leg with first segment of
tarsus enlarged containing silk-gland. Thorax elongated, almost
equal to abdomen. Cerci 2-segmented, asymmetrical in male.
 They are gregarious insects, which live under bark, in rocks or in
debris, in silken tunnels.

39. DICTYOPTERA
 Synonyms : Oothecaria, Blattiformia
 Dictyon - net work; ptera - wings
 Ex. Cockroaches and preying mantids.
 Head is hypognathous.
 Antenna is filiform.
 Mouthparts are chewing type.
 Tarsus is five segmented.
 Forewings are more on less thickened, leathery with a marginal
costal vein. They are called tegmina.
 Hindwings are large, membranous and folded fanlike and kept
beneath the forewings.
 Cerci are short and many segmented.
 Eggs are contained in an ootheca.

41. ISOPTERA
 isos=equal; pteron=wing
 ex. – Termites
 They are small (2-3 mm long) soft-bodied social insects having caste system.
The castes are queen, which is physogastric (having enormously enlarged
abdomen), males which are apterous in the nest and alate during nuptial flight;
workers having broad, chewing type of mandibles; soldiers having long, pointed
dagger-like mandibles for defence and in some colonies there are nasutes which
bear a long pointed snout for secretion of a highly corrosive fluid that can be
used to defend the colony or to make galleries through hard rocks.
 They are photophobous and live in underground nests called “termatoria” and
always move through galleries.
 Compound eyes are small or sometimes absent; ocelli also either two or absent.
 Head is prognathous and antennae moniliform. Mouthparts are mandibulate
type.
 Abdomen is broadly attached to the thorax. Legs are short adapted for slow-
walking and tarsi 4-jointed. Wings when present are of equal size.

42.  Termites, commonly called white-ants, live in underground nests,
over which they may make huge termite mounds for maintaining the
nest temperature. Some species also live in earthen galleries on the
trees.
 During breeding season termites produce a large number of male
and female winged forms, which come out of the nests and take to
nuptial flight, where mating takes place, after which they shed their
wings and crawl on the ground in search of a new nesting site.
 They excavate a small gallery and lay their first batch of eggs which
all hatch into workers which keep enlarging the nest.
 Once the nest is completed, the queen settles in the royal chamber
and starts enlarging her abdomen and reproductive organs, after
which her only job remains to lay eggs. She lays about 30,000 eggs
per day and survives to do this duty for about 30 years.
 Nuptial flight is the only way these subterranean creatures can
disperse to long distances.

44. ZOROPTERA
 zoros=purely; aptera=wingless)
 Ex. Zoropterans
 (Only one genus Zorotypus containing 20 species)
 They are small, pale, soft bodied insects resembling termites, with
large hypognathous head.
 Antennae moniliform, 9-segmented and the size of the segments
increases gradually from base to the apex.
 Mouthparts biting and chewing type.
 They are mostly without eyes and Ocelli but some species have
eyes.
 Legs are short and adapted for slow walking, with 2-segmented
tarsi. Cerci are short. They are gregarious insects but do not
display caste system. They feed on fungus and some are
predaceous on mites.
 Zorapterans are found in decaying wood or under the bark or in
humus

46. PSOCOPTERA
 The name refers to genus Psocus and its chewing and corroding habits
 Ex. Book lice, Bark lice
 They are small, fragile, light-coloured wingless insects with large hypognathous
head and depressed body.
 They have large compound eyes and 3 ocelli. Antennae are long and filiform.
Mouth parts are manbibulate, used for feeding on debris, book-glue or cereals.
 Book lice are wingless but bark lice are winged, having membranous wings, fore
wing being larger than hind wings. Wings are held tent-like over the abdomen
while at rest.
 Legs are slim, hind femora are enlarged and tarsal segments are1-3 segmented.
 Abdomen is 10-segmented and cerci absent.
 Adults can make ticking sound by striking venter against the loose wood or paper.
That is why sometimes they are called “death watch”. Psocopterans lay very large
egg which measures about one-third of their body size.

47. Bark lice
Booklice

48. MALLOPHAGA
 mallos=wool; phaga=to eat
 Ex.Bird lice
 Bird lice are very common on birds and can be collected from their
feathers by using wet alcohol dipped brush. They should be preserved
in 70% alcohol and mounted on slide in Canada balsam.
 This order contains 2000 species, which are ectoparasitic on birds,
some on mammals.
 They possess dorsoventrally flattened body with a tough integument.
Head is large and distinct, with short filiform antennae and strong biting
and chewing mouthparts.
 Compound eyes reduced and ocelli absent.
 Legs are short and adapted for clinging; tarsi 1-2 segmented, claws
two and curved. Abdominal segments 8-10 and cerci absent. Eggs are
glued to the feather base. There are 3 nymphal instars.
 They feed on feathers, hairs, skin, scales and on dried blood around
wounds.

50. ANOPLEURA/SIPHONCULATA
 anoplos=unarmed; uros=tail
 Ex. Sucking lice, human body and head lice
 There are 400 species in this order, which are all ectoparasites of
mammals.
 They are small grey or pale insects with dorso-ventrally flattened
bodies, with small head. Eyes are rudimentary and ocelli absent.
 Antennae 3-5 segmented and filiform. Mouthparts are modifies for
sucking.
 Legs are short and stout and joined on the side of the thorax. Tarsi
1-segmented. Claw single, long, curved and adapted for clinging
on to the hair. They are secondarily wingless.
 Abdomen 9-segmented and contains no cerci.
 They live on mammals at constant body temperatures and
transmit diseases such as relapsing fever, epidemic typhus and
trench fever.

52. HEMIPTERA
 Hemi - half; ptera - wing
 Ex. True bug
 Head is opisthognathous.
 Mouthparts are piercing and sucking type. Two pairs of bristle like stylets which
are the modified mandibles and maxillae are present. Stylets rest in the grooved
labium or rostrum. Both labial palps and maxillary palps are atrophied.
 Mesothorax is represented dorsally by scutellum.
 Forewings are either uniformly thickened throughout or basally coriaceous and
distally membranous,
 Cerci are always absent.
 Metamorphosis usually gradual; rarely complete.
 Alimentary canal is suitably modified to handle liquid food. (filter chamber)
 Salivary glands are universally present,
 Extra-oral digestion is apparently widespread.
 Abdominal ganglia fused with thoracic ganglia.

54. THYSANOPTERA
 Thysano - fringe; ptera - wings
 Ex. Thrips.
 They are minute, slender, soft bodied insects.
 Mouthparts are rasping and sucking. Mouth cone is formed by the labrum
and labium together with basal segments of maxillae. There are three
stylets derived from two axillae and left mandibles. Right mandible is
absent. Hence mouthparts are asymmetrical.
 Wings are either absent or long, narrow and fringed with hairs which
increase the surface area. They are weak fliers and passive flight in wind
is common.
 Tarsus is with one or two segments. At the apex of each tarsus a
protrusible vesicle is present.
 Abdomen is often pointed. An appendicular ovipositor may be present or
absent.
 Nymphal stage is followed by prepupal and pupal stages which are
analogous to the pupae of endopterygote insects.

56. NEUROPTERA
 Neuro-nerve; ptera - wings.
 Ex. Lace wings, Ant lions, Mantispidflies, Owlflies.
 They are soft bodied insects.
 Antenna is filiform, with or without a terminal club.
 Mouthparts are chewing type in adults.
 Wings are equal, membranous with many cross veins.
 They are held in a roof-like manner over the abdomen.
 They are weak fliers
 Larva is campodeiform with mandibulosuctorial mouthparts.
 Pupa is exarate. Pupation takes place in a silken cocoon.
Six out of eight Malpighian tubules are modified as silk
glands. They spin the cocoons through anal spinnerets.

57. Owl fly Aphid lion
Mantispid fly
Ant lion

58. MECOPTERA
 mekos=long; pteron=wigs
 Ex. Scorpion flies and Panorpids
 This order includes 500 species of small to medium sized, slender-
bodied insects having hypognathous head that is elongated into a
beak form and having strong biting and chewing type of mouth parts.
 Compound eyes are large and ocelli present or absent.
 Antennae are long and filiform. Wings are long and membranous,
held folded over the abdomen at rest.
 Legs are long and slender, with 5-segmented tarsi. Hind legs have
prehensile tarsi which are used for capturing prey.
 Abdomen of male is curved upward like the sting of a scorpion
(hence the name scorpion flies) but in female it is straight. Cerci are
short.

60. LEPIDOPTERA
 Lepido - scale; ptera - wings.
 Ex. Moths, Butterflies, Skippers
 Body, wings, appendages, are densely clothed with overlapping scales, which give colour,
rigidity and strength. They insulate the body and smoothen air flow over the body.
 Mouthparts in adults are of siphoning type. Mandibles are absent. The galeae of maxillae
are greatly elongated and are held together by interlocking hooks and spines. The
suctorial proboscis is coiled up like a watch spring and kept beneath the head when not in
use.
 Wings are membranous and are covered with overlapping pigmented scales. Forewings
are larger than hind wings. Cross veins are few. Wings are coupled by either frenate or
amplexiform type of wing coupling.
 Larvae are polypod-eruciform type. Mouthparts are adapted for chewing with strong
mandibles. A group of lateral ocelli is found on either side of the head. The antenna is
short and three segmented. There are three pairs of five segmented thoracic legs ending
in claws. Two to five pairs of fleshy unsegmented prolegs are found in the abdomen. At
the bottom of the proleg, crochets are present.
 Pupa is generally obtect. It is either naked or enclosed in a cocoon made out of soil,
frass, silk or larval hairs.

63. TRICHOPTERA
 trichos=hair; pteron=wing
 Ex. Caddis flies
 There are 3600 species in this order. They are medium-sized,
cryptically coloured insects with soft bodies, hypognathous head,
large compound eyes and long filiform antennae.
 Wings are covered with hairs and fore wings are larger; otherwise
they look like small moths.
 Mouthparts are poorly developed mandibulate.
 Legs are long and slender, with 5-segmented tarsi. Abdomen
bears 1or 2-segmented cerci.
 Adults feed on nectar and are short-lived.
 Larvae are aquatic and construct cases around their bodies by
secreting silk to which sand particles and debris are attached.

65. DIPTERA
 Di-two; ptera-wing
 Ex. True flies, Mosquitoes, Gnats, Midges,
 They are small to medium sized, soft bodied insects.
 The body regions are distinct.
 Head is often hemispherical and attached to the thorax by
a slender neck.
 Mouthparts are of sucking type, but may be modified.
 All thoracic segments are fused together. The thoracic
mass is largely made up of mesothorax. A small lobe of
the mesonotum (scutellum) overhangs the base of the
abdomen.

66.  They have a single pair of wings.
 Forewings are larger, membranous and used for flight.
 Hindwings are highly reduced, knobbed at the end and are
called halteres. They are rapidly vibrated during flight.
They function as organs of equilibrium.Flies are the
swiftest among all insects.
 Metamorphosis is complete. Larvae of more common
forms are known as maggots. They are apodous and
acephalous. Mouthparts are represented as mouth hooks
which are attached to internal sclerites. Pupa is generally
with free appendages, often enclosed in the hardened last
larval skin called puparium. Pupa belongs to the coarctate
type.

69. SIPHONOPTERA
 siphon=tube; aptera=wingless)
 Ex. Fleas
 This order consists of 1000 species of fleas, which are all parasitic
on birds and mammals and have small, compressed and highly
sclerotized dark bodies.
 Head is hypognathous with spines and sometimes with comb.
Compound eyes are reduced and ocelli absent.
 Antennae are pectinate, short and concealed in a groove.
 Mouth parts are piercing and sucking type.
 They are secondarily wingless insects having small thorax that is
closely united with the thorax.
 Legs are long and strong, hind legs being the longest, modified for
jumping. Claws adapted for clinging. Body covered with orderly
rows of spines.
 They are vectors of plague.

71. HYMENOPTERA
 Hymen - membrane; ptera – wings, Hymeno - god of marriage;
ptera - wings,(Marriage on the wings) (union of fore and hindwings
by hamuli)
 Ex. Ichneumonflies, Ants, Bees, Wasps.
 Mouthparts are primarily adapted for chewing. Mandibles are
very well developed. In bees both labium and maxillae are
integrated to form the lapping tongue.
 Thorax is modified for efficient flight. Pronotum is collar like.
Mesothorax is enlarged. Metathorax is small. Both prothorax and
metathorax are fused with mesothorax.
 Wings are stiff and membranous. Forewings are larger than
hindwings. Wing venation is reduced. Both forwings and
hindwings are coupled by a row of hooklets (hamuli) present on
the leading edge of the hindwing.

72.  Abdomen is basally constricted. The first abdominal segment is
called propodeum. It is fused with metathorax. The first pair of
abdominal spiracles is located in the propodeum. The second
segment is known as pedicel which connects the thorax and
abdomen. Abdomen beyond the pedicel is called gaster or
metasoma.
 Ovipositor is always present in females. It is variously modified for
oviposition or stinging or sawing or piercing plant tissue.
 Metamorphosis is complete. Often the grub is apodous and
eucephalous. Larva is rarely eruciform. Pupa is exarate and
frequently enclosed in a silken cocoon secreted from labial glands.
 Sex is determined by the fertilization of the eggs. Fertilized eggs
develop into females and males are produced from unfertilized
eggs. Males are haploid and females diploid.

74. COLEOPTERA
 Coleo - Sheath ; ptera-wing
 Ex. Beetles, Weevils
 They are minute to large sized insects.
 Antenna is usualy 11 segmented.
 Mouthparts are chewing type. Mandibles are short with blunt teeth at
the mesal face in phytophagous group. In predators the mandibles are
long, sharply pointed with blade like inner ridge. In pollen feeders teeth
are absent and the mandibles are covered with stiff hairs.
 Prothorax is large, distinct and mobile. Mesothorax and metathorax are
fused with the first abdominal segment.
 Forewings are heavily sclerotised, veinless and hardened. They are
called elytra. Forewings do not overlap and meet mid-dorsally to form a
mid-dorsal line. It is not used for flight. They serve as a pair of convex
shields to cover the hindwings and delicate tergites of abdomen.

75.  Hindwings are membranous with few veins and are useful
in flight. At rest they are folded transversely and kept
beneath the elytra. In some weevils and ground beetles
the forewings are fused and hindwings are atrophied.
 A small part of the mesothorax known as scutellum
remains exposed as a little triangle between the bases of
elytra.
 Cerci and a distinct ovipositor are absent.
 Metamorphosis is complete. Larva are often called grubs.
 Pupae are usually exarate and rarely found in cocoons.

78. STREPSIPTERA
 strepsis=twisted; pteron=wings
 Ex. Stylopids
 They are tiny insects having 300 species which are
parasitic on hoppers and bees. They exhibit sexual
dimorphism.
 Male: Small, measuring about one mm. Fore wing
reduced but hind wings large, membranous, fan like.
Mouth parts are vestigial, compound eyes are large,
with few large ommatidia. Ocelli absent. Legs long with
fore and middle coxae elongated.

79.  Female: It is wingless, incompletely developed, without
appendages, parasitic and spends the entire life inside the host
abdomen.
 Head and thorax fused and abdomen enormously enlarged.
Viviparous.
 Larvae are called Triungulin, which possess well developed eyes,
antennae and legs.
 They crawl out through the genital opening and find a new host
and penetrate into it through the intersegmental membrane.
 Then retrogressive metamorphosis takes place and the triungulin
loses appendages and eyes,
 which are regained only in the case of male after the last moult.
 Male mates with the female that continues to live in the host
abdomen through its genital opening and then dies in a day.

81. MANTOPHSMOTEDA
 Heel-walkers are brown, gray, green, or yellow and
are sometimes marked with darker dots or stripes.
The sides of their midsection, or thorax, are
sometimes spiny.
 They measure 0.35 to 0.94 inches (9 to 24
millimeters) in length.
 The males are usually smaller than the females.
Both sexes are wingless and resemble young
mantids or stick insects.

82.  The head is distinct and has chewing mouthparts with
sharp jaws that are directed downward. The antennae
are long, threadlike, and have many segments.
 The compound eyes, are well developed, but simple
eyes, are absent.
 The front and middle legs are slightly enlarged and have
two rows of short, sharp spines. The hind legs are
slender and lack rows of spines. All of the feet have five
segments, but the first three are fused, or joined
together.

83.  The abdomen consists of ten well-developed segments and a
much smaller eleventh segment. The tip of the abdomen has
a pair of projections. In females these projections are short,
but in males they are much longer and curved.
 They are found in dry, scrubby habitats that receive little rain.
Heel-walkers live down inside tufts of grass or grasslike
plants, where they blend in perfectly thanks to their spotted
and striped bodies.
 They eat various kinds of insects, including each other,
grasping and holding their prey with their strong and spiny
front and middle legs. Heel-walkers will eat all but the wings
and legs.