Fundamentals of Entomology

Position of insects in animal kingdom and their relationship with other Arthropods

• Insects are invertebrates grouped in the phylum Arthropoda (Arthro-joint, poda-foot) and subphylum Uniramia. Characters of the Phylum Arthropoda are

  1. Segmented body
  2. Segments grouped into 2 or 3 regions (tagma) known as Tagmosis.
  3. Renewable chitinous exoskeleton
  4. Grow by molting.
  5. Bilateral symmetry of body.
  6. Body cavity filled with blood and called as haemocoel.
  7. Tubular alimentary canal with mouth and anus at anterior and posterior ends.
  8. Dorsal heart with valve like ostia.
  9. Dorsal brain with ventral nerve cord.
  10. Striated muscles (with dark and light bands).
  11. No cilia (hair like vibratile structure on the surface of the cell).
  12. Paired, segmented appendages.
• Phylum Arthropoda is Classified in to 7 classes.

  1. Onychophora (claw bearing) e.g. Peripatus
  2. Crustacea (Crusta - shell) e.g. Prawn, crab, wood louse
  3. Arachnida (Arachne - spider) e.g. Scorpion, spider, tick, mite
  4. Chilopoda (Chilo - lip; poda - appendage) e.g. Centipedes
  5. Diplopoda (Diplo - two; poda- appendage) e.g. Millipede
  6. Trilobita (an extinct group)
  7. Hexapoda (Hexa- six; poda-legs) or Insecta (In- internal; sect – cut) e.g. Insects.