Megaloptera Click to enlarge image
Alderfly (Order Megaloptera) Image: Andrew Howells
© Australian Museum

Alderflies and dobsonflies belong to the Order Megaloptera.

What do alderflies and dobsonflies look like?


  • Wingspan 20 mm -100 mm.


  • Cigar-shaped.
  • Appears soft and fragile.


  • Thread-like, with many segments.
  • Shorter than body length.


  • Large, bulging and well separated.


  • For chewing or biting.
  • Held in front at rest.
  • Enlarged in some species, especially in males.


  • Two pairs.
  • Both pairs membranous and clear.
  • Both pairs have moderate cross-veins forming mainly rectangular cells.
  • Similar in length but hindwing usually wider than forewing due to a foldable lobe at the base of the wing.
  • At rest wings held tent-like over body, hindwing hidden.


  • Six legs, slender or stocky.
  • Held below body at rest.
  • Abdomen tip
  • Cerci (tails) absent.
  • Males may have claspers, which they use to hold the female during mating.

Where are alderflies and dobsonflies found?

  • Near water often on adjacent plants.

What do alderflies and dobsonflies do?

  • They are solitary. Females may group together to lay eggs but otherwise found in low numbers.
  • When disturbed they fly away.
  • They are weak, flapping fliers.
  • The adults do not feed and are short-lived.
  • They are active at twilight or during the night, and are attracted to light.

What looks similar?

  • Lacewings can be separated from alderflies and dobsonflies by their forked veins along the margin of their wings.
  • Stoneflies can be distinguished from alderflies or dobsonflies by cerci extending from their abdomen. Many stoneflies wrap their wings around their body at rest and hold their legs (which are bent at the 'elbows') out from their body. Stoneflies also tend to run rather than fly when disturbed.