Moths in the Cossidae, and Geometridae families

Species featured on this page

Latin name Common name Family
Cossus cossus Goat moth Cossidae
Xanthorhoe montana Silver-ground carpet moth Geometridae
Opisthograptis luteola Brimstone moth Geometridae
Cabera pusaria Common white wave Geometridae
Eulithis populata Northern spinach Geometridae
Odezia atrata Chimney sweeper moth Geometridae
Venusia cambrica Welsh wave Geometridae
goat moth caterpillar


There are 700 species in the world, but just three species of Cossidae in the British Isles. As adults the Cossidae do not have functional proboscis. They have long wings that are held like a steeply pitched roof over the body. The adults are nocturnal. The females lay their eggs in the stems of the host plant - always woody. The larvae feed in the wood and usually take at least a year before pupating.

Cossus cossus, the Goat moth (left)

The eggs are brown, and laid on the bark of ash, elm, willow, oak, birch, apple and poplar.

The caterpillar feeds on the inside of the trees. It takes three or more years of feeding on this low-quality food before it can pupate.

During the cold winter months it makes a kind of nest for itself and rests out the winter. When fully grown it can be up to 100 mm long. It gets its name from the rather unpleasant smell the caterpillars have.

It exits the tree to pupate in the ground making a hole as large as 20 mm in diameter.

The adults have a wingspan of 60-80 mm and and both front and rear wings are the same colour. They fly in June and July, usually around the foodplant trees, and the females are larger and fatter than the males. It is found throughout the UK, but is more common in the south, in Europe and eastwards as far as central Asia.

Geometridae - inch worms, loopers

There are around 20,000 species world wide and 312 British species. Most adult geometrids are nocturnal and rest with their broad, triangular-shaped forewings spread flat - see below - on each side of the body. They have a thin body, and a rather weak flight. In some species the females are flightless having reduced or vestigial wings. This means they have to walk to lay or disperse their eggs. A positive aspect of this is that they are able to do so in temperatures too low for flying; sometimes even below freezing. The caterpillars have only 2 pairs of prolegs (see above right), and their locomotion gives them the common names of inch worm, and looper, and many of them can mimic twigs when disturbed. They are often found in trees, and if knocked off will hang from a silk thread, then climb back up.

Geometridae caterpillar, inchworm caterpillar

Common white wave, Cabera pusaria

On the right is an adult Common white wave. The adults fly from May - August, and are fairly common in birch and alder woods. They have a wingspan of 25 - 30 mm, and a front wing length of 15 - 17 mm. The wings are shiny white with 3 rows of dotted lines on the fore wings, and 2 rows on the hind wings.

The caterpillars eat birch, alder, sweet chestnut, sallows and a variety of shrubs. There are 2 generations a year, and it overwinters as a pupa.

Common white wave, Cabera pusaria, adult

Brimstone moth, Opisthograptis luteolata

The brimstone (right) is common throughout Europe. They are found in hardwood forests, hedgerows, gardens and scrubland. There can be 2 or 3 generations a year, but just one in northern Scotland.

The caterpillar resembles a twig, and has an extra pair of prolegs, though these are smaller than the other 2 pairs. Its foodplants are hawthorn, blackthorn, plum, rowan and apple. It can reach a length of 33 mm.

Pupation is in a silken cocoon on or near the ground.

Adults fly from April to August (June and July in northern Scotland), and have a wingspan of 32 - 40 mm, and a front wing length of 14 - 21 mm. The female is usually larger than the male.

Eggs are laid in spring and all summer. There are 2 generations a year.

Brimstone moth adult, Opisthograptis luteolata
Silver ground carpet moth adult, Xanthorhoe montanata

Silver-ground carpet moth, Xanthorhoe montanata

The Silver-ground carpet (left) is common in the U. K. It is most often found in damp places with herbaceous vegetation, such as hedges, woodland edges, downland, gardens and heaths. It is common and abundant. The caterpillars feed on low-growing plants such as primrose and bedstraw. It overwinters as a caterpillar.

It pupates in a cocoon in the ground.

The adults fly from May to July. The wingspan is 24-28 mm, the front wing length is 14 - 17 mm, and the band of colour across the wings can vary in brightness.

Northern spinach adult

Eulithis populata, the Northern spinach

The Northern spinach at rest on the right and showing the underside of the wing on the right. It is widespread throughout Europe, but less common in southern England. It is found in mountains, heaths, bogs and fens. In the U. K. there is one generation a year.

Egg are laid in August, but do not hatch out until the following April.

The caterpillar foodplant is bilberry, cowberry, grey sallow, goat willow and other willows. The caterpillar feeds at night, resting on the foodplant by day with its

Northern spinach adult underside

body rigid, so it is not easy to see. Body length is up to 26 mm.

It pupates towards the end of May in leaves of the foodplant which it has sewn together.

The adults fly from June - August. The wingspan is 28 - 31 mm and front wing length 13 - 18 mm, the female is smaller than the male. The adult colours vary from straw yellow to brown. It overwinters as an egg.

Odezia atrata, the Chimney sweeper moth

Caterpillar. The caterpillar feeds on pignut flowers from April until early june.

It pupates just below the ground surface.

Adults. The Chimney sweeper is completely black except for the white edges around the tip of the forewings. This is difficult to see in sunny weather, so I brought this on inside to photograph it. This is a small, day-flying moth with a have a wingspan of 23 - 27 mm and a front wing length of 12 - 15 mm. It flies in sunny weather in grassy areas in June and July, and in August in Scotland.

It overwinters as an egg.

chimney sweeper moth, adult

Venusia cambrica, the Welsh wave

The Welsh wave tends to occur in the upland regions of Northern Europe, and in the U. K. in the north and west on moorland and open woodland.

Eggs are laid in July.

The caterpillar grows up to 21 mm long, and has a yellow-green body with a faint yellow line down its back, and irregular blotches of red/brown. The head is green. The foodplants are rowan and birch. The caterpillar feeds until it pupates at the end of August. It overwinters as a pupa in the soil or among plant debris.

The adult moth does not emerge until June the following year. Adult wingspan is 27 - 30 mm, and front wing length is 13 - 15 mm. It flies from June to August. By day it rests on rocks and tree trunks.

Welsh wave, Venusia cambrica, adult moth