Historically reported very widely, with records from Cornwall north to the Dornoch Firth. Still widely recorded in the 1980s and 1990s but just two records since 2000, from Speyside in 2014 and Staffordshire in 2019. Assessment against all criteria leads to a status of Endangered based on the decline in AOO over the last 10 years of 63%, the causes of which are not understood; the EOO has dropped too steeply to be calculable during the period 2006-2020. However, the broader presence in the 1990s prevents qualification against Criterion B.

Very much a southern species, including Wales and south-west England; the northernmost record is from Derbyshire (except for a single old Scottish outlier that requires verification). The data support an Endangered status under Criterion A on the basis of a reduction in EOO of 64% in the last 10 years, the causes for which are not understood.

There is a broad spread of records in England and Wales north to south Cumbria; absent from south-west England and south Wales to date. The records have continued at a low frequency to the present, although only five were noted between 1991 and 2020. The small recent AOO (20 km2) and number of locations (5), coupled with a continuing decline, are sufficient to classify the species as Endangered under Criterion B.

Records are distributed throughout much of Britain, but very local. The data support a status of Endangered, based on an estimated 74% decline in EOO between 2011 and 2021, the causes for which are not understood; this is supported by a 37% decline in estimated AOO over the same period (which would itself justify a Vulnerable status).

Recorded widely across much of Britain, but very localised or easily overlooked. Most of the 33 records collated were older ones, with those post-1990 being from Kent, south Wales, the Peak District and Bristol, the latter involving a series from an urban park over at least a 16-year period. The data support a status of Endangered, based on an estimated 70% decline in AOO between 2011 and 2021, the causes for which are not understood.

Very seldom recorded, with Benson (1952) aware of just three records, and only four more having come to light since. These have been distributed across southern England and just into south Wales. The status would have been assessed as Critically Endangered following an absence since 2004, except that one was found in 2022; the assessment period has been extended forward to take account of this record. The dataset now supports an status of Endangered under criterion A on the basis of an estimated 52% decline in AOO between 2012 and 2022, the reasons for which are not known. Endangered is also supported under criterion B, on the basis on a small recent AOO, small number of locations and continuing decline in AOO between 1992-2006 and 2007-2022.

Quite sparsely recorded across Britain north to Edinburgh. The data support an Endangered status under criterion A on the basis of an estimated 56% reduction in EOO between 2011 and 2021, the causes of which are not understood. One might wonder if there was competition between this species and the more recently arriving P. apicalis. Note that for this species, concave polygons were constructed using an alpha-parameter of 0.9 to give more appropriate comparative measurements (although this changed threshold did not affect categorisation).

A seldom recorded leaf-mining sawfly, with only about 16 records to date, mostly in England from Yorkshire southwards with one record in southern Scotland. The data support an Endangered status under criterion B on the basis of a low overall AOO, low numbers of locations and continuing decline in AOO between 1992-2001 and 2002-2011 (with no subsequent recovery).

A rarely-recorded species, with the majority of the 12 records from the Highlands (Speyside, Deeside, Sutherland) but also recorded from Cumbria. A record from the New Forest in 1907 would be far out of range and requires confirmation. Only three recent records, during 2006-08. The data support an Endangered status under Criterion B on the basis of a small recent EOO and AOO, small number of sites, and continuing decline between 2002-11 and 2012-21.

Assessments against all criteria lead to a status of EN, based on a small AOO, low number of locations and a decline in AOO over last 30 years, the latter relevant to both Criteria A and B. Although based on low numbers of records, the recent absence is noteworthy for a species formerly recorded widely in the south alongside an underlying significant increase in recording more generally. With just four locations, the species might also have qualified as D2 VU, but no plausible threat has been identified that is likely to drive the status to CR in a short period of time. There is no information on population size, precluding assessment against Criteria C and D1, and no life history model to inform assessments against Criterion E.