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Current Category » Fundamentals to Entomology

Order: Coleoptera

(Coleos = sheeth & pteron = wing)
E.g. Beetles and Weevils

Economic Importance:

Some insects are predators or scavengers; many are crop pests while some are destructive to stored grains.

Characters:

1. Minute large insects.
2. Fore wings modified into horny or leathery elytra which meet to form a mid-dorsal line, fore wings not used in flight.
3. Hind wings membranous, folded beneath the elytra or often reduced or wanting.
4. Mouth parts mandibulate.
5. Prothorax large and mobile, mesothorax reduced.
6. Abdominal tergiles often sclerotized.
7. Larvae campodaidorm or crucidorm, seldom apodous with mandibulate mouth part.
8. Pupal adecticous and exarate, rarely obtect.
9. Metamorphosis complete.

The order is divided into four sub-orders viz.

Archostemata, Myxophaga, Adephaga and Polyphaga Larvae of the insect belonging to sub-order Archostemata are wood feeders while the insect from sub-order Myxophaga are found in wet places by streams Comparative characters of the later two sub-orders are as follows:-

S.O. Adephaga

  1. Notopleural sulcus distinctly present in Prothorax.
  2. Wings usually with (2 cm cu –cross veins defining) an oblongum.
  3. Testes tubular and ovariole polytropic.
  4. Larvae with 6 segments in legs.

S.O. Polyphaga

  1. Notopleural sulcus never distinct in Prothorax.
  2. Wings have no oblongum.
  3. Testes follicular and ovariole acrotrophic.
  4. Larvae with 5 or fewer segments in legs, ending with single claw.

 

Important Families:

i. Cicindelidae e.g. Tiger beetle

ii. Dytiscidae e.g. Water beetle

iii. Carabidae e.g. Ground beetle

Sub-order: Polyphaga

1) Notopleural sulcus never distinct in Prothorax

Important Families:

i. Meloidae e.g. Blister beetle
ii. Coccinellidae e.g. Lady bird beetle, Epilachna beetle
iii. Scarabaeidae e.g. White grub
iv. Cerambycidae e.g. Mango stem borer, Grape stem girdler
v. Chrysomelidae e.g. Rice hispa
vi. Bruchidae   e.g. Pulse beetle
vii. Tenebrionidae e.g. Rust red flour beetle
viii. Dermestidae e.g. Carpel beetle, Khapra beetle
ix. Cucujidae   e.g. Saw toothed grain beetle
x. Bostrychidae e.g. Lesser grain borer
xi.Melolonthidae e.g. Cockchafer beetle
xii.Dynastidae e.g. Rhinoceros beetle
xiii. Curculionidae e.g. Weevils

Current Category » Fundamentals to Entomology