Order: Diptera
(dis – two & pteron = wing)
E.g. True flies (two winged insects)
Viz. Mosquitoes, Housefly, Horse fly, Fruit fly, Stem fly, Pod fly, Midges etc.

Economic Importance:

Consider number of flies is predaceous, some are blood suckers, some are well known human diseases transmitting agents and some are saprophagous. Fruit flies, leaf miners, Stem fly and Root maggots are crop pests.


1. Insects with single pair of membranous wings, hind pair of wings modified into halters.
2. Mouth parts suctorial, usually forming a proboscis and some times adapted for piercing.
3. Mandibles rarely present, labium usually distally expanded into a pair of fleshy lobes.
4. Prothorax and metathorax small and fused with the large mesothorax.
5. Tarsi commonly 5 segmented.
6. Larva Eruciform / apodous.
7. Pupa either free adecticous obtect / exarate or enclosed in the hardened larval cuticle (Puparium).
8. Metamorphosis complete.
Order Diptera has been classified into three sub-orders.
viz. Nematocera, Brachycera and Cyclorrhapha.

Comparative Characters of these Sub-orders are as Follows:

  1. Maggot with well developed exerted head and horizontally biting mandibles.
  2. Pupa normally obtect free (except in Cecidomyiidae)
  3. Antennae of image usually many segmented longer than the head and thorax, majority of segments not forming an arista.
  4. Palpi pendulous 4 or 5 segmented.
  5. Distal call absent e.g. Paddy gallfly.


  1. Maggot usually with retractile head and vertically biting mandibles.


  1. Pupa obtect free (except Stratio-myidae)
  2. Antennae of imago shorter than the head & thorax, generally three segmented, arista when present terminal.
  3. Palpi porrect 1 or 2 segmented.
  4. Distal cell always present e.g. Horse fly.


  1. Maggot with a vestigial head e.g. Housefly.


  1. Pupation in a puparium, pupa.


  1. Antennae of imago 3- segmented with dorsal arista.



  1. Palpi 1 segmented.
  1. Distal cell usually present e.g. Jowar stem fly.


Important Families:

Sub-order: Nematocera

i. Cecidomyiidae e.g. Paddy gall fly, Sesamum gall fly.
ii. Culicidae     e.g. Mosquitoes.
iii. Chironomidae e.g. Midge fly (midges).

Sub-order: Brachycera

i. Tabanidae e.g. Horse flies.
ii. Asilidae e.g. Robber flies etc.
iii. Bombyliidae e.g. Bee fly.

Sub-order: Cyclorrhapha

i. Tephritidae (Trypetidae)      e.g. Fruit fly.
ii. Agromyzidae                      e.g. Tur pod fly, Pea stem fly.
iii. Tachnidae                           e.g. Tachinid fly.
iv. Anthomyiidae                    e.g. Jowar stem fly.
v. Micropisidae                       e.g. Rhizome fly.

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