Insect legs are segmented and consist of 5 segments - coxa, trochanter, femur, tibia, and tarsus. Legs are modified for different habitats and behaviors, including walking, running, jumping, climbing, digging, grasping, swimming, sticking, basket-like, sucking, and food collecting. The document describes the structure and modifications of each leg type.

1. Insect Leg
Structure and Modification
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2. Insect legs are typically segmented type
Legs are present in pro, meso and metathoracic
segments
Each leg consists of 5 segments
1. Coxa
2. Trochanter
3. Femur
4. Tibia
5. Tarsus
Pretarsus
Legs are modified into severaltypes based on
habitat and food habit
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Legs of Insect

3.  First or proximal leg segment
 It is freely movable and attached with
thoracic pleuron
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1. Coxa (Pl. Coxae)
Legs of Insect
2. Trochanter
Second segment of leg which is small
and single segmented
Seems to be 2 segmented in dragonfly,
damselfly etc
The apparent 2nd trochanter is called
“trochantellus” (actually a part of
femur)

4. Largest and stoutest part of leg closely attached to
trochanter.
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3. Femur
Legs of Insect
4. Tibia
Long and provided with downward projecting
spines (help in climbing and footing). Tibia in many
insects armed with large movable spurs near apex
5. Tarsus
Segmented structure, Individual segment known as
tarsomere (1-5) except in protura, diplura and some
larval forms. Basal tarsomere is larger and called
basitarsus

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Legs of Insect
Pretarsus
It is the 6th segment or last part of legs representing the
foot. It is characterized by possessing a pair of terminal
little curved, claws. The claw is also known as ungues.
The tarsus at its end consists of pretarsus which is in the
form of a pair of claws and cushion like pulvilli.
The pulvilli bear a large number of pores and hairs which
secreate the adhesive secreation that help in walking on
the slippery surfaces.
In between the claws, if there is lobe like structure, it is
known as “aroleum” as in Orthoptera (grass hopper).
If bristle like structure, it is called “empodium” as in
Diptera.

6. Adapted for walking
Femur flat, long tibia & well defind femoro-
tibial joint. It can move perfectly on smooth &
rough surfaces
Ex- Dermaptera, Bugs, some beetles, Fore and
middle legs of grasshopper
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1. Ambulatorial (Walking) leg

7. Adapted for running
Thin & tubular with flattened femur
Highly muscular coxa
Tibia & tarsi slender & elongated
Ex- Cockroach, Tiger beetle
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2. Cursorial (Running) leg

8. Adapted for leaping or jumping
Trochanter fused with femur.
Femur is enlarged to accommodate
powerful extensor muscles of tibia
Long and slender tibia with two rows of
spines along the ventrolateral edges
At tibial end, four spurs are fopr gaining
grip against substratum.
Ex- Hind leg of Grasshoppers, Crickets
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3. Saltatorial (Jumping) leg

9. Adapted for clinging
Single segmented tarsus bears a long
hook like curved claw with ventral
pad.
Tibia possess a thumb like fleshy lobe
at its apex
 Ex-head louse, body louse, bird lice
(Mallophaga)
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4. Scansorial (Climbing or Clinging) leg

10. Adapted for digging
Fore legs/front legs are modified for digging into
the soil & for cutting the roots inside the soil
Front tibia & tarsus are modified for this
purpose. They are flattened & as shaped like
shovels
Coxa, trochanter & femur are short & strong but
not modified
Front tibia is divided in to server finger like
branches & each branch is modified into strong
pointed tooth like lobe are used for digging
 Ex-Mole cricket, Nymphs of Cicade
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5. Fossorial (Digging) leg

11. Forelegs are for capturing the prey, not used for
locomotion
Coxa is long and mobile (helps in capturing prey)
Femur is large and grooved along the ventral
surface with spines
Spiny tibia fits into femoral groove when it snaps
down over the prey
Tarsus consisting of 5 tarsomeres
 Ex- Forelegs of preying mantids
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6. Raptorial (Grasping) leg

12. Hind legs are adapted for swimming
Femur, tibia, and first four tarsomeres
are broad and flattened.
Edges are provided with flattened setae
 Ex- Hind legs of water bug and water
beetle
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7. Natatorial (Swimming) leg

13. Pairs of lateral adhesive pads under claw
called pulvilli
Arolium is absent but median spine like
structure empodium is present
Pulvilli covered with glandular tenant hairs.
Secretions of these tenant hairs help the
insect I walking and clinging to smooth
surface
 Ex- All legs of housefly
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8. Sticking leg

14. Legs are situated just behind the head and
are anterior in position
Legs are spiny and closely placed useful for
seizing the prey and captured insects are
kept in the leg basket.
vesicle- Modified arolium
Legs are not useful for locomotion.
 Ex- Legs of dragonfly and damselfly
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9. Basket like leg

15. The forelegs of same aquatic beetles are
provided with suckers on the metatarsi &
stumpy tarsomers in males for holding the
female during mating.
Tarsus id flattened with adhesive disc
A viscous secretion from the sucker in the
tarsus is discharged so that they adhere to
surfaces they are applied.
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10. Suctorial (Clasping) leg

16. Thick, fleshy and not segmented (found
in caterpillar, 2-5 pairs)
They are shed with larval moult
Tip of proleg is called planta, clawas are
known as crochets
Last pair of abdominal proleg is Clasper.
 Ex- Abdominal legs of caterpillar
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11. Prolegs/ False legs/ Pseudolegs

17. Corbiculate legs
Ex- All legs of honeybee
Fore legs
(Eye brush, Antenna cleaner,
Pollen brush)
Middle legs
(Pollen brush, Tibial spur)
Hind legs
(Pollen basket, pollen packer,
pollen comb)
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12. Foragial (Food collecting) leg

18. Corbiculate legs
Ex- All legs of honeybee
Fore legs
(Eye brush, Antenna cleaner,
Pollen brush)
Middle legs
(Pollen brush, Tibial spur)
Hind legs
(Pollen basket, pollen packer,
pollen comb)
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12. Foragial (Food collecting) leg

19. Corbiculate legs
Ex- All legs of honeybee
Fore legs
(Eye brush, Antenna cleaner,
Pollen brush)
Middle legs
(Pollen brush, Tibial spur)
Hind legs
(Pollen basket, pollen packer,
pollen comb)
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12. Foragial (Food collecting) leg

20. Corbiculate legs
Ex- All legs of honeybee
Fore legs
(Eye brush, Antenna cleaner,
Pollen brush)
Middle legs
(Pollen brush, Tibial spur)
Hind legs
(Pollen basket, pollen packer,
pollen comb)
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12. Foragial (Food collecting) leg

21. Thank You…