Blattodea Click to enlarge image
Cockroach, Order Blattodea Image: Andrew Howells
© Australian Museum

Cockroaches belong to the Order Blattodea.

What do cockroaches look like?


  • 3 mm - 70 mm in length.


  • Oval, flattened as if pressed from above.
  • Segment behind head shield-like, overhanging body and often covering base of head.
  • Appears hard.


  • Thread-like, length variable.


  • Large and well separated.
  • Cave-dwelling cockroaches may have reduced or no eyes.


  • For chewing or munching.
  • Held downwards at rest.


  • Two pairs if present.
  • Forewings are hardened and cloudy.
  • Hindwing membranous and clear.
  • Both wings lack cross veins and are of similar size.
  • At rest, wings are held flat to body, with forewings overlapping, and hindwing hidden.


  • Six legs with many spines.
  • Slender, designed for running.

Abdomen tip:

  • Two cerci (tails) never longer than the body and have one or more segments.

Where are cockroaches found?

  • They are adaptable to most environments.
  • The majority of Australian natives are found amongst leaf litter, under bark and rocks, and within rotting logs and crevices.
  • Others live in trees or underground in burrows or caves.
  • Introduced species are often found in the house.

What do cockroaches do?

  • They often group together sometimes in large numbers, but are usually solitary.
  • When disturbed they runaway, usually undercover and fast; rarely fly.
  • They are weak fliers, usually flying in short bursts.
  • Introduced species feed on plant or animal debris; native species primarily feed on plant debris.
  • Most are active at night, however some do openly bask in sunlight.

What looks similar?

  • Beetles can be distinguished from cockroaches by their hardened forewings. These forewings, or rather elytra, never overlap but meet in the middle. Beetles also never possess cerci.