1. LOCOMOTION IN INSECTS

2. Thorax
The body section after the head, with the legs and wings attached.
The: the prothorax, the mesothorax, and the metathorax.
Each segment bears a pair of walking legs, the first pair of wings arise from the meso thorax while the second pair from the metathorax

3. Insect leg attachment and structure
Each leg pair is attached to a segment of the thorax.
The front pair to the prothorax,
the second pair to the mesothorax and
the third to the metathorax.
Most insect legs consist of six segments, and they are as follows in order, from the thorax to the tip of the leg:

4. Each segment bears a pair of walking legs,
the first pair of wings arise from the meso thorax while the second pair from the metathorax
The exoskeleton of each thoracic segment is formed by four chitinous sclerites

5. Four Chitinous sclerites
A dorsal tergite or tergum
Lateral pleurite or pleuron
ventral sternite or sternum
Arthrodial membranes ( which join the sclerites from adjacent segments)

6. Walking legs Each leg consists of five segments
Coxa: articulating between the pleuron and sternum
Trochanter : freely movable on the coxa but fixed to the femur
Femur : usually broad and long
Tibia : long and uniformly thick
Tarsus : last segment having five tarsomeres or podomeres or metatarsals with last tarsus having 2 claws

7. Coxa Trochanter Femur Tibia, 1 2 Tarsus (tarsomeres1-5 3 4 5 claws
Coxa Trochanter Femur, Tibia, Tarsus claws 1 2
Tarsus (tarsomeres1-5 3 4 5
claws

8. Cursorial
Cursorial : Periplaneta americana

9. Saltatorial
Grasshopper
Grasshopper hind leg

10. Raptorial Stagmomantis sp (Praying mantis)

11. natatorial leg (predaceous diving beetle hind leg)

12. fossorial leg ) Grylotalpa africana
fossorial leg in Grylotalpa Africana ( cricket foreleg)
Grylotalpa africana

13. WINGS
The wings are actually two layers of epidermis covered by a thin layer of cuticle.
Most of the orders of Pterygota have four wings.
Some, like the Diptera have only two wings.
Each wing pair is attached to a segment of the thorax, more specifically the last two pairs, the mesothorax and the metathorax

14. Wings
The wings are jointed to the second and third thoracic segments and are moved up and down by the action of muscles. As in the case of limbs, the muscles are attached to the inside of the exoskeleton. There are two types of attachment for either direct or indirect flight muscles

15. Section through the thorax to show direct muscle attachment
when this muscle contracts it pulls the wing down
when this muscle contracts it pulls
the wing up

16. Direct flight muscles
One end of each muscle is attached to the inside of the thoracic segment; the other end is attached to the wing near the joint. The muscles act directly on the wing

17. Attachment of indirect flight muscles
these muscles deepen the thorax and flip the wing down
these muscles slightly flatten the thorax and flip the wing up

18. Indirect flight muscles
These act on the thorax and distort it, so flipping the wings up and down. This produces a rapid wing beat. There are also muscles which adjust the angle of the wings

19. Abdomen
Spiracles
Genitalia

20. Diagram of insect tracheal system
main trachea
spiracles

21. The breathing system in insects consists of a series of tubes called tracheae.
The tracheae connect to the atmosphere by openings called spiracles.
Air diffuses through the spiracles and tracheae to all parts of the body supplying the organs directly with air.

22. finely branched tracheae (tracheoles) supplying muscle fibres with air
spiracle
Muscle fibre
main trachae
spiracle
Body cuticle

23. Insect Genitalia
The insect's genital opening lies just below the anus:   it is surrounded by specialized sclerites that form the external genitalia.   In females, paired

24. In females, paired appendages of the eighth and ninth abdominal segment fit together to form an egg-laying mechanism called the ovipositor.
).   In males, the genital opening is usually enclosed in a tube-like aedeagus which enters the female's body during copulation (like a penis).  

25. The external genitalia may also include other sclerites (e. g
The external genitalia may also include other sclerites (e.g. subgenital plate, claspers, styli, etc.) that facilitate mating or egg-laying.   The structure of these genital sclerites differs from species to species to the extent that it usually prevents inter-species hybridization and also serves as a valuable identification tool for insect taxonomists.