1801       Perizoma taeniata (Stephens, 1831)   BARRED CARPET

A local species restricted to western and northern Britain, the larva feeding on the capsules and contained spores of mosses growing in moorland and montane habitats. “Of the record there is no doubt, but no explanation of the occurrence occurs to one. This insect is a northern and mountain insect, confer however Golden-rod Brindle₂₂₃₃ a similar occurrence.” (W Parkinson Curtis): Bloxworth, a single specimen (O Pickard-Cambridge).

1802       Perizoma affinitata (Stephens, 1831)   RIVULET

A species found over much of Britain, but local in northern Scotland, the larva feeding in the flowers and seed capsules of red campion (Silene dioica). In Dorset, the moth is at low density but widespread, frequent in the west and north but becoming scarcer further east, typically occurring on hedgebanks and in woodland where Red Campion abounds. Care is needed in identifying potential Rivulet as they superficially resemble the Small Rivulet₁₈₀₃. Diagnostics include: a larger species; emerges up to a month earlier; the single circular indentation two-thirds of the way down the postmedian fascia on this species is diagnostic (compare with the double indentation half-way down on the Small Rivulet₁₈₀₃):

1803       Perizoma alchemillata (Linnaeus, 1758)   SMALL RIVULET

A generally distributed species in Britain, the larva feeding in the flowers and seeds of hemp-nettle (Galeopsis spp.) and woundwort (Stachys spp.). In Dorset, the moth is widespread and frequent. Host plants in the county are bifid hemp-nettle (Galeopsis bifida), betony (Stachys officinalis), hedge woundwort(Stachys sylvatica) and marsh woundwort (Stachys palustris). The table indicates the diverse range of habitats occupied by each of these plant species:

1804       Perizoma bifaciata (Haworth, 1809)   BARRED RIVULET

A species occurring over all but northern Britain, the larva feeding in the seed capsules of red bartsia (Odontites vernus) and eyebright (Euphrasia nemorosa). In Dorset, the moth is local and at low density on chalky unimproved grassland and verge habitat; it occurs regularly on Portland, at Weymouth, Badbury Rings and Durlston, where larvae have been found on red bartsia. Elsewhere, records are thinly scattered across various habitat and soil types, hinting at occasional dispersal. Old records suggest it was more widespread in the past, and loss of unimproved grassland on chalky soils has evidently precipitated a contraction in the range of this species.

1807       Perizoma albulata [Denis & Schiffermüller 1775]   GRASS RIVULET

A widespread species in Britain, the larva feeding in the seed capsules of yellow rattle (Rhinanthus minor). In Dorset, this early summer moth is rare and has declined as the unimproved grassland, particularly hay meadow, within which its host plant flourishes, has mostly been ploughed and re-seeded since the Second World War and such changes in farm practices have meant that arable no longer provides a haven for wild flowers in the way it once did. Localities where yellow rattle still supports colonies of the moth are few and far between: Fontmell Down, Stubhampton Bottom, Slepe Heath and Durlston. The colony within Durlston Country Park is particularly robust probably because a sizeable portion of it is managed as hay meadow with yellow rattle predominating. The hay meadows are subject to grazing and rotational cutting with different cycles applied to different aged compartments.

1808       Perizoma flavofasciata (Thunberg, 1792)   SANDY CARPET

A frequent species over much of Britain, but local in northern Scotland, the larva feeding in the seed capsules of red campion (Silene dioica), white campion (Silene latifolia), and bladder campion (Silene vulgaris). In Dorset, the moth is at low density but widespread. It rises to frequent on chalky soil where arable and grassy verges support white campion, and in the west of the county on hedgebanks and in woods where red campion thrives.

1809       Perizoma didymata (Linnaeus, 1758)   TWIN-SPOT CARPET

A generally distributed species in Britain, the larva feeding on bilberry (Vaccinum myrtillus), sallow (Salix spp.), heather (Erica spp.), willowherb (Epilobum spp.), dock (Rumex spp.) and other plants. In Dorset, the moth is local and the principal habitat yielding regular sightings is deciduous woodland on chalky or neutral soil: Powerstock Common, Lyscombe Hill, Fifehead Wood, Yellowham Wood, Melcombe Park, Chase Wood, Kings Wood, Boys Wood. Colonies of the moth were evidently established atNorden and Studland historically. Many received records when queried, reveal that the recorder was unable to differentiate at the time between Red Twin-spot Carpet₁₇₂₄ and Dark-barred Twin-spot Carpet₁₇₂₅, so wrote down ‘Twin-spot Carpet’.