Geographical races of the extinct British Maculinea arion

There has been much celebration in Britain to have successfully reintroduced the Large Blue [ Maculinea arion arion ] from Swedish stock which is said to be almost identical with the extinct British race, however the latter is simply not true. Britain had its own endemic subspecies eutyphron [ Fruhstorfer 1915] which had a very interesting range of geographical variation in the different isolated colonies. M. arion specimens from the Cotswold Hills [Glos] were usually very dark and those from the North coast of Cornwall and Devon becoming a much brighter blue.

Here is what the Oxford don. E. B Ford in his seminal work ' Butterflies ' [1945] in the New Naturalist series had to say on the matter " On the Cotswolds it appear in June or even late May, and it is of a rather dark iron-blue shade. This species emerges a little later in Cornwall, where the specimens are of a clearer and brighter blue, while the spots on the upper-side are rather larger, though they may be less numerous than in the Gloucestershire examples. The extinct race from Barnwell Wold, Northants more resemble the Cotswold insects. Ancient specimens from the Langport district of Somerset, where the species is also presumably extinct, are similarly of the darker blue shade, but they are remarkable for the larger size of their spots, either on the upper or the under-side of their wings, or both. Those from the Salcombe district of South Devon on the whole resemble the Cornish form, though some of the specimens are of a rather duller tint. The butterfly does not appear to have been caught in the area for a long time, though it was formerly thought to be its chief stronghold but I have seen specimens that were taken there in 1892".

In the outstanding ' The Aurelian's Fireside Companion by M. Salmon and P. Edwards [2005] there is a fascinating British history of M. arion by various lepidopterists who recorded details of collecting arion and its decline and extinction of the different colonies and there is an absorbing account of the discovery of the early stages in 1915 by Capt Edward Bagell Purefoy [1953]. Before 1800 there were records of this species from Folkstone [ Kent] the Marlborough Downs [Wilts], Winchester [ Hants], the hills near Bath [North Somerset] and Cliveden in Bucks but the butterfly was not recorded at these localities after that date. By the late 19th century it was gone from Somerset [ Langport nr Taunton] Bedfordshire [ Bedford ] South Devon [ Bolt Head ] Northants [ Barnwell Wold] and Millook in south-east Cornwall. By the 1950's it had become extinct in all of its Gloucestershire [ Cotswolds] localities. It hung on in North Cornwall but the loss there was soon followed by the last colony on Dartmoor in Devon in 1979. Although it is not possible to be able to see the British races today in the wild, it is now one of the great delights of the summer to view arion again in some of its old haunts.

Many thanks to Clive Pratt for allowing some of his outstanding M. arion collection to be photographed. Also shown here are two historic J. C. Dale specimens from the Oxford Natural History Museum collection. Many treasures here for sure. These are certainly some of my favourite specimens.

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The dark race of M. arion from the Cotswold Hills [ Glos]. The specimens in the centre are from Great Witcombe near Gloucester.. Most of the Cotswold colonies contained the dark phenotype.


M. arion from Bude on the North coast of Cornwall