1. Entomology
By Dr. Fan dong

2. Insect Thorax
The thorax consists of three segments - the prothorax (front), the mesothorax (middle) and the metathorax (back).
Each of these segments bears a pair of jointed legs.

3. In winged insects, the meso- and metathoracic segments each bear a pair of wings--the forewings and hindwings
forewings
hindwings

4. In many insects one or both pairs of wings have been lost, or modified into other structures, during the course of evolution.

5. Construction of thorax
Prothorax:
Pronotum
Propleuron: pleural sulcus-episternum and epimeron
prosternum

6. Construction of Pterothorax
Notum: three sulcus: antecostal sulcus, prescutal sulcus, scutoscutellar sulcus
Acrotergite, prescutum, scutum, scutellum
Anterior notal wing processes and posterior notal wing processes

7. scutellum

8. Construction of Pterothorax
Pleuron : pleural sulcus-episternum and epimeron
Sternum : two sulcus: presternal sulcus and sternacostal sulcus
Eusternum (presternum , basisternum , sternellum) and intersternite

9. Thoracic legs coxa trochanter femur tibia tarsus pretarsus: claws
pulvillus
arolium

11. Mosquito’s femur (2070x)

12. Drosophila: claw and pulvillus

13. Types of thoracic legs Walking legs : ambulatorial legs
Jumping legs : saltatorial legs
Grasping legs : raptorial legs
Digging legs : fossorial legs
Swimming legs : natatorial legs
Clasping legs
Pollen-carrying legs : corbiculate legs
Clinging legs : scansorial legs

16. Walking legs

17. Digging legs

18. Jumping legs

19. Grasping legs

20. Pollen-carrying legs

21. Clasping legs

22. Swimming legs

23. Clinging legs

24. Insect wings

25. Functional wings exist during the adult stage
Membranous, parchment-like, or heavily sclerotized
Most insects have two pairs of wings -- one pair on the mesothorax and one pair on the metathorax

26. Purpose of Flight in Insects
Search for food or a resting habitat
Escape from enemies and search actively for mates
Be able to spread over the globe; if conditions became unfavorable in one place, they took to the air to find another
                                                         

27. Function of wings serve as organs of flight
protective covers (Coleoptera and Dermaptera)
thermal collectors (Lepidoptera)
gyroscopic stabilizers (Diptera)
sound producers (Orthoptera)
visual cues for species recognition and sexual contact (Lepidoptera).

28. In most cases, a characteristic network of veins runs throughout the wing tissue.  
These veins are extensions of the body's circulatory system.  
They are filled with hemolymph and contain a tracheal tube and a nerve.   In membranous wings, the veins provide strength and reinforcement during flight.  
Wing shape, texture, and venation are quite distinctive among the insect taxa and therefore highly useful as aides for identification.

29. Structure of insect wing

30. Apical angle of a mosquito (80x)

31. Special wing modifications include the structures called halteres found in the Diptera (true flies), and the structures called elytra (singular: elytron) found in the Coleoptera (beetles) and Dermaptera (earwigs):

32. Membranous wings: such wings are very thin and like cellophane
Types of insect wings
Membranous wings: such wings are very thin and like cellophane

33. Elytra -- hard, sclerotized front wings that serve as protective covers for membranous hind wings
Coleoptera

34. Hemelytra -- front wings that are leathery or parchment-like at the base and membranous near the tip
Hemiptera

35. Tegmina -- front wings that are completely leathery or parchment-like in texture

36. lepidotic wings: Scaly wings -- front and hind wings covered with flattened setae (scales)
Lepidoptera

37. Piliferous wings: Hairy wings -- front and hind wings clothed with setae
Trichoptera

38. Fringed wings -- slender front and hind wings with long fringes of hair
                                                

39. Halteres
-- small, club-like hind wings that serve as gyroscopic stabilizers during flight

40. Halteres

41. front wings and hind wings

42. Jugate form

43. Frenulum -- Bristle near base of hind wing that holds front and hind wings together
Lepidoptera

44. amplexi form

45. Hamuli -- tiny hooks on hind wing that hold front and hind wings together
Hymenoptera

46. fold form

47. Wing Venation Insect contained 7 longitudinal veins.
These veins (and their branches) are named according to a system devised by John Comstock and George Needham -- the Comstock-Needham System

48. longitudinal veins Costa (C) -- the leading edge of the wing
Subcosta (Sc) -- second longitudinal vein (behind the costa), typically unbranched
Radius (R) -- third longitudinal vein, one to five branches reach the wing margin
Media (M) -- fourth longitudinal vein, one to four branches reach the wing margin
Cubitus (Cu) -- fifth longitudinal vein, one to three branches reach the wing margin
Anal veins (A1, A2, A3) -- unbranched veins behind the cubitus
Jugal veins ( J )

49. Crossveins crossveins abbreviation longitudinal veins ligated
humeral crossvein
radial crossvein
sectorail crossvein
radiomedial crossvein
medial crossvein
mediocubital crossvein h r s
r-m m
m-cu
C/Sc
R1/R2
R5/R4, or R2+3/R4+5
R4+5/M1+2
M2/M3
M3+4/Cu1

50. Variation of veins Increase：accessory veins –R1a, R1b
intercalary veins—IM1
Decrease: combination

51. Cells
Cell
Enclosed cell
Open cell
Open cell
Enclosed cell

52. Veins and cells

53. Articulation
Articulation is an important condition for wing’s all sort of activities.
At the end of wings there are some ossicles as joints-pteralia
Humeral plate
Axillary plates
First axillary plates;
second axillary plates;
third axillary plates
Median plates
Inner median plate
Outer median plate
tegula

54. Wings’ placement
When insect is resting , wings’placement have three types:
Open and flat: dragonfly ; some moths; mosquitoes
Upright on the back: mayfly ; some butterflies
Fore wings cover the back wings: beetles; bugs,grasshoppers

55. Flying
Wing’s movement: up and down; back and forth