Notes on the extinct British Cyaniris semiargus: The last Records and Specimens and a new online Paper.
In the Entomologist's Record and Journal of Variation for 1955, the assistant editor wrote of Cyaniris semiargus " It is not a known migrant and the last authentic example of the indigenous race taken in England, were by Evan Johns at Dursley in 1865. In South Wales semiargus lingered on until 1877". In his 'The History of our British butterflies', C.W. Dale recorded that " In Tenby in Pembrokeshire, South Wales one was taken by Mr Edwards, flying over wild thyme in 1883". A colony of this species existed in meadows of Epworth in Lincolnshire, England that may have survived until the early part of the 20th century. No Lincolnshire specimens of C. semiargus seems to be extant. See the link to the paper below.
G.B. Kershaw's brother, Colonel Sidney H. Kershaw D.S.O. (1881-1964) of Bletchley in Buckinghamshire, wrote a short article in the Entomologist's Record and Journal of Variation for 1955: "I think I can claim the last record of the capture of Cyaniris semiargus Rott in Great Britain for my late brother; in late August or early September 1905. It was in a meadow, some way up a stream in Llanbedrog in North Wales not far from Aberystwyth. His wife drew my brother's attention to a butterfly in a cobweb. He identified it as semiargus and a female, and shortly afterwards took a male flying close by quite fresh. Both specimens are now in my collection. He did not see any others during the rest of his stay".
The C. S. Kershaw Cyaniris semiargus cobweb female specimen and the male that was also taken by him. Private Collection.
If the two North Wales Cyaniris semiargus specimens were in fact, taken at the same time, as S.H. Kershaw suggests, then the data on the male shown may be erroneous, it may have been transcribed wrongly or is it possible that Kershaw was mistaken? These almost certainly-genuine captures by G.B. Kershaw have been ignored in modern literature. S.H. Kershaw's large collection was not presented to a museum, but was bought by private collector. Perhaps the unusual dates of the C. semiargus captures are considered questionable but in some years it may have been double brooded in Britain. The early Aurelian William Lewin recorded this butterfly from Bath in Somerset during August.
Not to be out done, I. R. P. Heslop wrote in the same volume of the Entomologist's RJV (1955) regarding Cyaniris semiargus that " and in the Bristol area I have no doubt that a colony of this species, the exact location of which was never discovered, survived until 1921. Apart from traditions and rumours of occurrence, two definite specimens in the Bristol area came within my preview. One was taken in 1916 on the Gloucestershire side. I was familiar with the specimen and the place of actual capture. Finally one was taken by a school fellow and seen by me freshly killed in 1921, but the location of the capture must have been close to the city, could not be determined". Heslop would have been well aware in 1921 that Cyaniris semiargus had supposedly become extinct during the 19th century. The whereabouts of the two Bristol specimens are unknown.
Not every one believed the North Wales Kershaw semiargus records, even though both brothers why highly respected field collectors. Of the 20th Century C. semiargus specimens, the Kershaw seem to be the only ones that have survived. R.F. Bretherton wrote of the North Wales records of C. semiargus in Emmet and Heath's 'The butterflies of Great Britain and Ireland'... " two caught in North Wales August and September 1907 must remain doubtful”.
Viewing the drawers of C. semiargus in the BMNH, I was surprised to find that there was a specimen from North Wales taken around 1867, which shows this species once existed in that area and in my mind there is no doubt that the Kershaw examples of C. semiargus are genuine. The BMNH specimen is shown for the first time here being currently unavailable online.
19th century specimen of C. semiargus from North Wales. British collections BMNH.
There have been a few records of this species since the extinction of the native colonies. Those are thought to be either vagrants from the continent or introductions. These records are detailed by Bretherton in the volume mentioned above.
A new detailed paper of this species ' Of Lincolnshire High Skies, Hay Meadows and Mazarine Blues Cyaniris semiargus' has been written by Martin White and can be found at