Nymphs
Squash Bugs go through five nymph stages (instars), shedding their skin after each stage. Only the adults have fully developed wings.
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Classification
from Australian Faunal Directory
Order Hemiptera - bugs, hoppers and scale insects
Suborder Heteroptera - true bugs, 2806 named species in Australia
Family COREIDAE - Crusader Bugs or Squash bugs, 92 species in Australia
Genus Amorbus
Species Amorbus alternatus