The Barred Rivulet, Perizoma bifaciata, is a moth

Moth

A moth is an insect closely related to the butterfly, both being of the order Lepidoptera. Moths form the majority of this order; there are thought to be 150,000 to 250,000 different species of moth , with thousands of species yet to be described...

 in the group of geometer moth

Geometer moth

The geometer moths or Geometridae are a family of the order Lepidoptera...

s (Geometridae).

Appearance

It is small (wingspan 18–21 mm), thin, and more or less brown all over. The forewing can vary in colour from light golden-brown to dark red-brown, often with a wide, darker coloured band in the centre, but this can vary. The band is covered on both sides with a wide, doubled, irregular white band. The wings have a white, triangular exterior. The lower wing is grey/white. The larva

Larva

A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...

 is light grey/green with short, white patches.

Life cycle

The species has larvae which live near plants such as odontites

Odontites

Odontites is a genus of flowering plants in the family Orobanchaceae. One of its species, the Odontites granatensis, endemic to the Sierra Nevada in Spain, was so threatened that in 1993 only 1,500 plants survived in two locations; due to conservation efforts the plant has made a comeback,...

 and large specimens of euphrasia

Euphrasia

Euphrasia is a genus of about 450 species of herbaceous flowering plants in the family Orobanchaceae , with a cosmopolitan distribution. They are semi-parasitic on grasses and other plants...

, both in the figwort family (Scrophulariaceae

Scrophulariaceae

Scrophulariaceae, the figwort family, are a family of flowering plants. The plants are annual or perennial herbs with flowers with bilateral or rarely radial symmetry. Members of the Scrophulariaceae have a cosmopolitan distribution, with the majority found in temperate areas, including...

). This species hibernates as pupae, sometimes for many years, which is unusual for geometer moth

Geometer moth

The geometer moths or Geometridae are a family of the order Lepidoptera...

s. The grown butterflies fly in July-August.

External links

• www.nhm.uio.no/norlep/ Norges sommerfugler - A Norwegian-language website on Norwegian butterflies.
• Picture of larva, from Kimmo's Lep site: http://www.kolumbus.fi/silvonen/lnel/g11/Perbifac.htm