Subclasses

• Subclass Apterygota


  • Wingless insects, the wingless condition being primitive
  • Metamorphosis absent or very slight
  • One or more appendages present other than genitalia and cerci
  • No veterinary importance
• Subclass Pterygota


  • Winged insects, possessing wings in the adult stage or secondarily wingless
  • Metamorphosis very varied, rarely slight or absent
  • No abdominal appendages other than genitalia or cerci
• Exopterygota (outside)

  • The wings develop externally as buds
  • Metamorphosis is simple, rarely a pupal stage
  • The immature stages usually resemble the adults in structure and habit
• Divisions of Exopterygota

  • Orthoptera – grasshopper, cockroaches
  • Dermaptera – earwig
  • Plecoptera – stone flies
  • Isoptera – termites
  • Psocoptera – book lice
  • Mallophaga – biting lice
  • Siphunculata (Anoplura) – sucking lice
  • Odonata – dragon flies
  • Thysanoptera – thrips
  • Hemiptera - bug
• Endopterygota (inside)

  • The wings develop internally
  • Metamorphosis is complete
  • Pupal stage is present
  • The immature stages is totally different from the adult
• Divisions of Endopterygota

  • Coleoptera – beetles
  • Hymenoptera – bees, wasps
  • Lepidoptera – butterflies, moths
  • Neuroptera – lace wings
  • Siphonaptera – fleas
  • Diptera – true flies
• Coleoptera (beetles)


  • Important growth in Parasites