Plesanemma fucata (R. Felder & Rogenhofer, 1875)
Lemon Gum Moth
(previously known as Chlenias fucata)
Don Herbison-Evans
Stella Crossley

(Photo: courtesy of Merlin Crossley, Melbourne, Victoria)

This Caterpillar has a fearsome horn on its head. This is purplish-red and an extension of the prothorax. Actually, it is soft, and coils and flexes as the animal moves, and is quite harmless. A red-edged yellow dorsal line runs from this horn along the back of the body to the pointed tip of the abdomen.

(Photo: courtesy of Tamara Boland and Elizabeth Leblanc, Australian Landscape Trust, Renmark, South Australia)

The rest of the body is green, and the head is purplish red. The front pair of ventral prolegs is slightly reduced in size. The caterpillar rests on the surface of a leaf of the food plant on a mat made out of silk. Often, several individuals sit side by side on the mat. They grow to a length of about 3.5 cms.

(Photo: courtesy of the Macleay Museum, University of Sydney)

The caterpillars feed on the foliage of Gum Trees (MYRTACEAE), especially:

  • Lemon Scented Gum (Corymbia citriodora).

    (Photo: courtesy of Sarah Leighton, Fremantle, Western Australia)

    Pupation occurs in a flimsy cocoon beneath the soil debris. A specimen that pupated in Melbourne in September emerged the following April.

    (Photo: courtesy of CSIRO/BIO Photography Group, Centre for Biodiversity Genomics, University of Guelph)

    The colour of the adult moths is varied. The forewings are pale creamy orange in some specimens, and dark orange or tan in others. The females are inclined to be darker than the males. There are usually three substantial spots on each forewing: a dark brown one at the base, and dark red ones edged in black in the basal area, and in the outer area of the wing,

    Plesanemma fucata
    female, drawing by Rudolf Felder & Alois F. Rogenhofer, listed as Chlenias fucata,

    Reise der Osterreichischen Fregatte Novara,
    Band 2, Abtheilung 2 (5) (1875), Plate CXXIV, fig. 11,
    Image courtesy of Biodiversity Heritage Library, digitized by Smithsonian Libraries.

    The females have recurved forewing tips, whereas the males have rounded forewing tips. The forewings are often also speckled with brown spots and dots. The hindwings vary in colour from plain cream to pale orange. The wingspan is about 4 cms.

    (Photo: courtesy of Elaine McDonald, Nicholls Rivulet, Tasmania)

    Typically, the eggs are laid near the edge of a leaf, either singly or in piles. They are egg-shaped with a pronounced conical distortion. Initially they are cream, but become blue-black after a few days.

    female with eggs
    (Photo: courtesy of Merlin Crossley, Melbourne, Victoria)

    The species is found over much of Australia, including :

  • Queensland,
  • New South Wales,
  • Australian Capital Territory,
  • Victoria,
  • Tasmania,
  • South Australia, and
  • Western Australia.

    female, underside
    (Photo: courtesy of Elaine McDonald, Nicholls Rivulet, Tasmania)

    Further reading :

    Cathy Byrne,
    Characterisation of the Australian Nacophorini and a Phylogeny for the Geometridae from Molecular and Morphological Data,
    Ph.D. thesis, University of Tasmania, 2003.

    Ian F.B. Common,
    Moths of Australia, Melbourne University Press, 1990, p. 364.

    Pat and Mike Coupar,
    Flying Colours, New South Wales University Press, Sydney 1992, p. 51.

    Rudolf Felder & Alois F. Rogenhofer,
    Reise der Osterreichischen Fregatte Novara,
    Band 2, Abtheilung 2 (1875), p. 6, and also Plate 124, fig. 11.

    Marilyn Hewish,
    Moths of Victoria: Part 5,
    Satin Moths and Allies - GEOMETROIDEA (A)
    Entomological Society of Victoria, 2014, pp. 5, 18-19, 32-33, back cover.

    Peter B. McQuillan,
    A new genus for Chlenias fucata Felder and Rofenhofer (Lepidoptera: Geometridae: Ennominae) and a new Tasmanain species,
    Journal of the Australian Entomological Society,
    Volume 23 (1984), pp. 297-306.

    Peter B. McQuillan, Jan A. Forrest, David Keane, & Roger Grund,
    Caterpillars, moths, and their plants of Southern Australia,
    Butterfly Conservation South Australia Inc., Adelaide (2019), p. 126.

    Australian Butterflies
    Australian Moths

    (updated 17 September 2011, 5 August 2017, 15 July 2020)