1. GENERAL CHARACTERS
OF CLASS INSECTA

2. The insects abound in all habitats – water land and air
The insects abound in all habitats – water land and air. Most of them are free-living, but some are parasites on animals and plants.
A few are colonial and social. The class Insecta is the largest class of the animal. Every fifth organism on this earth is an insect.

3. Characteristics of class-Insecta
some characteristics of Insecta are
Body :-
Divided in to three distinct regions
Head , thorax and abdomen
Head :
One pair of antennae (olfactory)
One pair of compound eyes and many simple eyes called ocelli Mouthparts variously modified for piercing and sucking, siphoning, sponging,
biting and chewing
Thorax :-
Three segmented
Each segment with a pair of legs
Two pair of wing on meso and metathorax
Abdomen :-
Consist of eleven or fewer segments ,
with out appendages Except a pair of
anal cerci on last segment
Gential opening at posterior
end of abdomen

4. Classification of insecta
Class inseta is divided into two sub classes
Apterygota ( primitive wingless insects)
Pterygota ( winged and secondarily wingless insects)
The sub class Pterygota is divided in two division
Exopterygota – insects with simple meta mortphosis with out pupal stage
Endopterygota – insects with complete meta morphosis including a pupal stage

5. Apterygota Order Thysanura Bristletails Order Diplura
Diplurans (Two-pronged Bristletails)
Order Protura 
Proturans
Order Collembola 
Springtails

6. Exopterygota Order Ephemeroptera Mayflies
Order Odonata 
Dragonflies and Damselflies
Order Orthoptera *
Grasshoppers, Locusts and Crickets
Order Dictyoptera 
Cockroaches and Mantids
Order Grylloblattodea 
Rock crawlers
Order Phasmida 
Stick insects and Leaf insects
Order Dermaptera 
Earwigs
Order Isoptera *
Termites
Order Embioptera 
Web-spinners
Order Plecoptera 
Stoneflies
Order Zoraptera 
Zorapterans
Order Psocoptera 
Psocopterans (Psocids, Booklice)
Order Mallophaga 
Chewing lice (Biting lice)
Order Anoplura  (= Siphunculata)
Sucking lice
Order Thysanoptera *
Thrips
Order Hemiptera
   suborder Heteroptera *
Bugs
   suborder Homoptera *
Cicadas, Hoppers, Psyllids, Whiteflies, Aphids, and Scale insects
Exopterygota
Order Ephemeroptera 
Mayflies
Order Odonata 
Dragonflies and Damselflies
Order Orthoptera *
Grasshoppers, Locusts and Crickets
Order Dictyoptera 
Cockroaches and Mantids
Order Grylloblattodea 
Rock crawlers
Order Phasmida 
Stick insects and Leaf insects
Exopterygota
Exopterygota
Order Ephemeroptera 
Mayflies
Order Odonata 
Dragonflies and Damselflies
Order Orthoptera *
Grasshoppers, Locusts and Crickets
Order Dictyoptera 
Cockroaches and Mantids
Order Grylloblattodea 
Rock crawlers
Order Phasmida 
Stick insects and Leaf insects
Order Dermaptera 
Earwigs
Exopterygota
Order
Ephemeroptera  Mayflies
Odonata  DragonfliesandDamselflies
Orthoptera Grasshoppers, Locusts and Crickets
Dictyoptera  CockroachesandMantids
Phasmida  Stick insects and Leaf insects
Dermaptera  Earwigs

7. order Isoptera Termites
Plecoptera Stoneflies
Psocoptera  Psocopterans (Psocids,Booklice)
Mallophaga  Chewing lice
Anoplura  Sucking lice
(Siphunculata)
Thysanoptera Thrips
Hemiptera   
suborder Heteroptera Bugs
suborder Homoptera  Cicadas, Hoppers, Psyllids, Whiteflies, Aphids, and Scale insects

8. Endopterygota Order Neuroptera
Alderflies, Dobsonflies, Fishflies, Snakeflies, Lacewings, Antlions, and Owlflies
Order Coleoptera 
Beetles
Order Strepsiptera 
Twisted-winged parasites (Stylopids)
Order Mecoptera 
Scorpionflies
Order Trichoptera 
Caddisflies
Order Lepidoptera 
Butterflies and Moths
Order Diptera 
True Flies
OrderSiphonaptera 
Fleas
OrderHymenoptera
Sawflies, Ichneumons, Chalcids, Ants, Wasps, and Bees

9. Thysanura Include silver fish Soft bodied No wings
Body covered with silver scales hence silver fish
Chewing moth parts and feed on starch
Metamorphosis absent

10. Important characters of the common orders of class insecta
Collembola
Include Spring tails
Soft bodied insect
No wings
Chewing mouth parts and feed on decaying plant and fungis
Furcula present at end of abdomen that helps in leaping like a spring
Metamorphosis absent

11. Orthoptera
Includegrasshopper ,Cricket
Forewings leathery called tegmina
Hindwing thin veined
Chewing mouth parts – herbivorous
Metamorphosis Gradual (Egg,nymph,adult)
Metalegs enlarged for jumping

12. Dictyoptera
Include cockroach and mantis
Forewings leathery called tegmina
Hindwing thin veined
Chewing mouth parts carnivorous , omnivorous
Metamorphosis gradual
Prolegs large grasping ( mantis)

13. Phasmida
Include stick insect, leaf insect
Body modified to mimic twigs or leaves
Forewing leathery , Hind wings thin
Mouthparts chewing –herbivorous
Metamorphosis gradual

14. Forewing short leathery veinless
Dermaptera
Include earwigs
Forewing short leathery veinless
Hindwings large semicircular radially veined
Mouthparts chewing –feed on insects
Metamorphosis gradual
Cerci unjointed and form forceps

15. Plecoptera
Include stoneflies
Forwings thin narrow
Hindwings thin broad
Chewing mouthparts- feed on insects
Incomplete Metamorphosis (Egg, Naiad, Adult)

16. Isoptera
Include Termites
Both wings thin and veined
Chewing mouth parts – feed on wood
Gradual Metamorphosis

17. Odonata
Include dragon and damsel flies
Huge eyes
Both wing thin , alike , richly veined
Chewing mouth parts – feed on mosquito
Incomplete Metamorphosis

18. Ephemeroptera
Include may flies
Both wings thin and large
Chewing mouthparts ( Naiad feed on greenvegetation)
Metamorphosis incomplete
Abdomen has very long two or three terminalfilaments

19. Mallophaga
Include Biting lice
Wings absent , Eyes reduced
Chewing mouthparts –feed on fragments of feather
Metamorphosis gradual

20. Anoplura
Include sucking lice
Wing absents
Piercing and sucking mouthparts
Metamorphosis gradual
Tarsi one jointed with single grasping claw

21. Hemiptera
Include Bugs and its allies
Piercing and sucking mouthparts that from a beak
Large compd. Eyes
Basal portion of forewing thick and apex is thinner and transparent
Gradual Metamorphosis

22. Suborder Homoptera –
Include cicadas , aphids, scale insects
Membranes of fore wings typically translucent
Beak arises from posterior portion of head
Head has tentorium
Plant feeders

23. Suborder Heteroptera :-
Include Bugs
Base of front wings are thinkened and apex is membranous
Beak arises from front end of head
Head without tentorium
Many are predacious

24. Include Antlions, lace wings, alder flies
Neuroptera
Include Antlions, lace wings, alder flies
Look like dragonflies but have knobbed antenna
Wing thin and alike having many veins and crossveins
Chewing mouth parts –mostly predacious
Complete Metamorphosis (Egg, Larva, Pupa, adult)
Alder fly
lace wings

25. Coleoptera
Include Beetles and weevils
Large prothorax
Forewing thick , veinless called elytra
Chewing mouthparts feed on plants, grains
Metamorphosis complete

26. Hymenoptera
Include bees, wasps,ants,
First abdominal segment is fused with the thorax and next two segments are
constricted to from a narrow pedicel
Wings thin, locked during flight with hamuli
Chewing,lapping sucking mouthparts
Metamorphosis complete

27. Diptera
Include flies , Mosquitoes
Forewings are veined , membranous and
transparent
Hind wings reduced to small knobs –Halteres
Mouthparts sponging or piercing and sucking type
Metamorphosis complete

28. Lepidoptera
Include butterflies and moths
Body soft covered with scales ( Modified setae)
Antennae long tapering ( Moth ) Knobbed ( Butterfly)
Both wings membranous covered with powdery scales
Mouthparts siphoning in adults and chewing in caterpillars
Metamorphosis complete

29. Siphonaptera Include ectoparasitic fleas Body laterally compressed
Antennae short
Compound eyes absent , ocelli present
Wings absent
Mouthparts piercing and sucking
Metamorphosis complete

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