Lepidoptera associated with the Eastern Counties

99

REVIEW OF BRITISH LEPIDOPTERA

lapidea Hübn.) from Eastbourne in early October. These were only the second and third British records for this species. Two further specimens of the Silver Spangle (Plusia confusa Steph.) were reported from localities as far apart as Penrith and Ashford in Kent. The third British example of the Eastern Blackneck (Tathorhyncus exsiccata Led.) was taken in Cornwall, while a new noctuid emanating from North America, Plusia biloba Steph, was recorded from Wales. Among the more regulär migrant moths several of the Whitepoint (Leucania unipuncta Haw.) were captured along the south coast.

But by far the most spectacular event of the season took place in the first days of October in south-east Kent where a considerable number of the Giant Ear (Hydraecia hucherardi Mab.) were obtained at light, only eight have been seen in 1953. The discovery that the larvae feed in the roots of the Marsh Mallow (Althea officinalis) was one of the most notable contributions to British Entomlogy in recent years.

Apart from these rarities the usual species of moths which appear in the autumn were distinctly scarce, but in spite of the extremely unpropitious weather during the summer 1954 was by no means an unproductive year.

March, 1955.

NOTES ON SOME LEPIDOPTERA MAINLY ASSOCIATED WITH THE EASTERN COUNTIES By

BARON DE W O R M S , M . A . ,

PH.D.,

F.L.S.,

F.R.E.S.

In " Collecting Lepidoptera in the Eastern Counties ; Some Reminiscences " (Trans, viii. 43) I mentioned a number of species whose headquarters can be said to be still in the counties of Norfolk, Suffolk, Essex, Cambridgeshire and Huntingdon. I have thought it of interest to say something about the present and past status of these insects most of which can be classed as very local. I do not propose, however, to enumerate a number of species which were formerly found chiefly in this area, but are now presumed to be virtually extinct throughout the British Isles. These include the following nine insects :—The Large Copper (Lycaena dispar

100

NOTES ON SOME LEPIDOPTERA

Linn.), The Gipsy Moth (Lymantria dispar Linn.), the Reed Tussock (Laelia coenosa HĂźbn.), the Rosy Marsh Moth (Caenophila subrosea Steph.), The Orache (Trachea atriplicis Linn.), the Small Ranunculus (Hadena dysodea Schiff), the Marsh Dagger (Apatele strigosa Fab.), the Many-lined (Euphyia polygrammata Borkh.), the Frosted Yellow (Isturgia limbaria Fab.). Their history has been so admirably dealt with by Mr. R. F. Bretherton (Entom.

Gazette 1951. ii. 211—240) that it would be presumptuous and superfluous for me to enlarge further upon them.

One of the chief features of the area under review is the extent of the marshland which is probably greater than in any other part of the country and which harbours a larger proportion of the lepidoptera affecting this type of terrain. It is indeed for these fen and marsh species that the Eastern Counties have above all been famous. Another most important area is the Breck district which has special features of its own and several species peculiar to it. There is also along the coast an abundance of sandhills and saltmarsh, while inland there are big areas of chalk and a fair amount of woodland. Unfortunately recent developments in cultivation together with the spread of airfields has made serious inroads on some of the localities where several of the very local insects used to flourish.

I have selected the following 24 species for review.

T h e SWALLOW-TAIL (Papilio machaon Linn.). This, the only butterfly to be treated, is in many ways the most spectacular of all our indigenous species. One of the peculiarities of our race britannicus is that it is now confined to our fenland areas where the foodplant of the larva is the Milk Parsley, whereas the insect which is widespread over the whole of the Palaearctic Region, affects every type of terrain and the larva abroad feeds on many kinds of Umbelliferae. Happily our fine race with its heavy marking still flourishes all over the Norfolk Broads where the first melanic variety was obtained in the 1920's. T h e other most noted locality has been Wicken Fen where it could be seen annually in good numbers among the reed beds. For the last three years none have been seen there.

It is greatly to be feared that it has died out from this renowned sanctuary. Outside these two areas it is doubtful now that the Swallow-tail is truly indigenous. It is probable that it bred formerly in the Tuddenham Fen area and in the marshes round Beccles. There have been a large number of the records of this butterfly outside these areas, notably in 1945 when there were at least 24 examples seen or captured in Suffolk alone. Considering that the year was one of the most notable for migration, it is more than likely that those taken were of the pale Continental form, though it is known that a colony of the British race was put down near Fritton. In former

NOTES ON SOME LEPIDOPTERA

101

times the ränge of the Swallow-tail was over the whole of the Fen country to Yaxley near Peterborough, while 150 years ago it was common in Hackney and Tottenham marshes in the London area.

The G R O U N D LACKEY (Malacosoma castrensis Linn.). The Ground Lackey can well Said to be more prevalent in the Eastern Counties than elsewhere in the country, since it inhabits almost all the saltmarsh regions from Benfleet on the north side of the Thames Estuary to the Southwold area in Suffolk, yet abroad the species is a denizen of open country and even woodland. The large colonies of larvae which feed chiefly on sea-aster readily survive the frequent flooding by the tide as also do the pupae which have been Seen floating in masses on the sea. In Suffolk larvae swarmed at Walberswick in 1939, but have not been seen there since. One larva was found at Bawdsey in 1940 and a few at Havergate Island in 1951 and 1954. Outside the East coast the species occurs sporadically along the Kent side of the Thames from Greenwich to Sheppcy, while some thirty years ago a colony was found on the Sussex coast. T h e moth is occasionally taken at light in August.

The DOTTED FOOTMAN (Pelosia muscerda Hufn.). This charming little member of the Footman moths is one of the specialities of the Norfolk Broads where it is often to be seen in profusion in early August fluttering among the reeds at dusk or Coming to the sugar patch. It is probably widespread in this area, but has seldom been seen outside it. One was taken in recent years round Fritton Lake, but I have never heard of it in the main Suffolk marshes where I have often collected in late July. The species was formerly obtained in the marshes near Sandwich in Kent, but I know of no recent records from this area.

The REED LEOPARD (Phragmatoecia castaneae HĂźbn.). This somewhat unusual member of the family of the Cossidae is yet another species almost exclusive to our Fenland country of the Eastern counties. Chippenham and Wicken Fens are still its headquarters. In these two localities the males often come in profusion to light in the summer months, but the long-bodied females are usually only to be found freshly emerged on the reed stems. T h e species occurs in the Norfolk Broads where it is said to have been introduced by C. G. Barrett. Outside these areas, it is only known from a remote marsh near Wareham in Dorset where it was discovered in the early 1930's. A much smaller race occurs here than in the Fens. There are a few other sporadic records notably from marshes along the River Lea, north of London.

The POWDERED WAINSCOT (Simyra albovenosa Goeze.). This member of the Dagger family, so like in appearance to the true Wainscots, is one of the most familiar inhabitants of the large

102

NOTES ON SO ME LEPIDOPTERA

tracts of marshlands in the main Fens and Broads of Norfolk, Suffolk and Cambridge. Its striking black and yellow larva, similar in some respects to that of the Large White, can often be found feeding in the open on the reeds, while the moth is frequent visitor to light in June and again in August. It is numerous in most of the marshes along the Suffolk coast, to Dunwich. Outside the Eastern Counties it has been found in several areas along the Kent and Sussex coast as well as in the Isle of Wight and even in marshes along the River Lea to the north of London.

T h e VIPER'S BUGLOSS (Anepia irregularis Hufn.). This very pretty member of our Noctuid moths is one of the most local species we have, since it is confined to the Breckland in Norfolk and Suffolk where its foodplant, the Nottingham Catchfly (Silene otites) only occurs. Formerly when there was far less cultivation and development in this area, this plant used to be found in plenty on waste and fallow land. In some restricted localities it was possible to find the larvae of this species in hundreds in late July.

But since the war the increase in arable land has greatly restricted the foodplant and also the ränge of the moth. Mr. G. Haggett has written a most interesting account of his observations on the species in recent years (1952 Entom. 85. 36). It was indeed gratifying in 1954 to find quite a large growth of the Silene.

The moths were Aying about it freely after dark and later in the season the larvae were quite numerous. Let us hope that protection may once more help to preserve one of our most attractive species.

The PALE L E M O N SALLOW (Mellinia ocellaris Borkh.). Although originally discovered in the London area in 1893 and at one time occurring freely along the lower reaches of the Thames Valley, the Eastern counties can now be considered the headquarters of this autumn species. It is still plentiful in late September round large poplars in the Barton Mills district where larvae can be obtained in quantity from fallen catkins in the spring. It was at one time found commonly at Sudbury in Suffolk. It reappeared in the Thames Valley in 1949 in small numbers.

T h e REED WAINSCOT (Nomagria cannae Ochs.). At one time this internal feeding species of the " Wainscots " was considered to be a speciality of a small area of the Norfolk Broads. It used to be quite an undertaking rowing round Barton Broad in early August trying to locate pupae in the stems of the Scirpus with which the species always seems to be associated. Latterly the species has been found to be fairly widespread in a number of secluded lakes in Sussex. In 1952 it was bred from south-east Kent, while in 1953 it was discovered in Co. Galway, Eire in small loughs where the Scirpus flourishes.

NOTES ON SOME LEPIDOPTERA

103

The SUSSEX W A I N S C O T (Nonagria neurica HĂźbn.). This species which until 50 years ago was confused with its near relative the Brown-veined Wainscot (Nonagria dissoluta Treits.) was about that period only known from one very restricted locality in Sussex whence it disappeared more than 20 years back. In 1924 the late Sir John Fryer discovered it in the East Suffolk marshes whence an occasional specimen was bred or obtained at light. In 1950 Mr. P. J. Burton and myself secured it at light there in some numbers, while in 1954 it was found plentifully by Mr. Austin Richardson. It is hoped that it will continue to breed in the many spots along the Suffolk coast where it doubtless occurs.

F E N N ' S W A I N S C O T (Arenostole brevilinea Fenn.).

This insect is yet another exclusive inhabitant of the Eastern Counties where it was discovered in 1864 on the Norfolk Broads. At one time it was considered to be confined to this area and found nowhere outside the British Isles. . However, in recent years it has turned up in Holland and during the last decade it was taken in North Suffolk. In late July 1952 Mr. P. J. Burton and I found it in the Southwold marshes and it doubtless occurs in other similar areas southwards along the Suffolk coast.

The CONCOLOROUS (Arenostola extrema HĂźbn). This small white Wainscot which was ofiginally discovered at Yaxley Fen in 1844 is another of our most local species, being confined at present to a few localities in Huntingdon and probably only one in Northants. In Woodwalton Fen where it still occurs freely, it is to be found at dusk in late June Aying over its foodplant, the wood small reed (Calamagrostis apigeios) or Coming to light at a very late hour, usually about 2 a.m. or even dawn.

The M E R E W A I N S C O T (Arenostola hellmanni Ev.). This attractive little moth feeds on the same plant as the last but appears at least a month later.

It is still one of the specialities of Wicken and of a few small fens in Cambridgeshire and Suffolk, especially on the edge of the Breckland, but it also occurs in a few places outside these areas notably in Northants, Dorset and Devon.

I took one specimen on the sandhills at Lowestoft in 1948. In 1954 it was especially abundant at light near Cambridge.

The LYME-GRASS W A I N S C O T (Arenostola elymi Treits.). This is yet another of the Wainscots which is regulated by the distribution of a special foodplant, the Lyme-grass (Elymus arenarius), though the insect is not necessarily found wherever this grass occurs, as on the south coast. T h e species appears to be confined in this country to the East coast, starting on the sandhills in the southern part of Suffolk and continuing at intervals right up to Forfar in Scotland. During the summer months the moth is to be seen in numbers at rest on its foodplant after dark.

104

NOTES ON SOME LEPIDOPTERA

T h e FLAME WAINSCOT (Meliana flammea Curt.). This is another truly fen marshland species with definite headquarters in the Eastern Counties where Wicken and Chippenham Fens are among its most noted haunts, though it found fairly plentifully in late May on the Norfolk Broads and in the coastal marshes round Blythburgh and Dunwich in Suffolk. Apart from these areas it is only known from one marsh near Wareham in Dorset and from another near Southampton, though it may occur sporadically along our south-east coast.

M A T H E W ' S WAINSCOT (Leucania favicolor Barrett).

Though this insect is considered by some to be only a saltmarsh form of the Common Wainscot (L.pallens Linn.), it has many distinguishing features from the latter species. Since its original discovery on the East coast in 1895, it has been found to occur in almost all saltmarsh areas ranging southwards from Waldringfield in Suffolk, all round the Essex coast to Southend, thence across the Thames estuary to Sheppey and also in the Chichester Harbour district of Sussex and Hants. It comes freely to sugar in late June. It has recently been discovered on the Northern coast of Germany.

T h e MARSH M O T H (Hydrillula palustris HĂźbn.). For quite 100 years this insect might be termed a " mystery moth " . Its appearance mainly in the Eastern Counties was most uncertain and nothing was known of its life history in this country tili 1944 when Mr. H. M. Edelsten and the late Sir John Fryer gave a most illuminating account of it (Entom. 77. 49), from larvae found at Woodwalton Fen where the moth occurs in fair numbers.

In 1954 the species was taken in Holme Fen, Hunts. Prior to this last decade Wicken and Chippenham Fens were its chief haunts.

In 1932 two examples were taken in early June near Mildenhall.

The only other records are from Norwich, Lincoln, York and Carlisle. The tiny female has seldom been seen in the wild.

T h e SILVER-BAR (Eustrotia argentula HĂźbn). This most delightful little Noctuid moth is one of the noted inhabitants of Wicken, Chippenham and Tuddenham Fens where it can often be flushed in large numbers from long herbage in the daytime about the turn of the summer. In spite of its fen-like habitat it appears to be found in no other area of the British Isles except in the immediate vicinity of Killarney in Eire. Here it is equally abundant and differs only from the English race in its larger size.

T h e SPOTTED-SULPHUR (Emmelia trabealis Scop.). This is another of our Breckland specialities, as there are very few records of this species outside this area where in pre-War days it was often abundant in rough fields in which the bindweed flourished. But the recent increased cultivaton has seemed to make it extremely scarce of late and in 1954 hardly a specimen was seen in its old haunts. It normally appears twice a year, in June and August and is not difficult to rear on field bindweed.

NOTES ON SOME LEPIDOPTERA

105

The ESSEX EMERALD (Euchloris smaragdaria Fab.). Another species which is virtually confined to the Eastern Counties in which it ranges along the saltmarshes at Benfleet in the Thames Estuary all round the Essex coast as far as Harwich. The curious ornamented larvae are a familiar sight in the autumn on their foodplant the sea wormwood (Artimesia maritima), but are much less easy to find after hibernation. The recent coastal defence works have destroyed a lot of the plant along the sea walls. The moth which is seldom seen in the wild, has also been reported from the Isle of Sheppey.

The T A W N Y W A V E (Scopula rubiginata Huf.). This very pretty little geometer used to be very common in most areas of the Breckland in uncultivated ground. Latterly it has become appreciably scarce and was quite difficult to obtain in 1954.

Though the Breck is its stronghold, it has occurred in the Northern Counties and occasionally along the south coast, notably in Dorset.

The G R E Y CARPET (Lithostege griseata Schiff.). This is the fourth species which can be said to be peculiar to the Breckland where it is only known to occur.

It is welcome news to know that in spite of recent adverse conditions this little insect continues to flourish mainly in the northern part of the district where it can be flushed from stony ground about the middle of June. The moth seems to simulate small white stones prevalent on the loose soil of the area. Flixweed (Sysimbrium) appears to be its foodplant.

T h e M A R S H CARPET (Coenotephria sagittata Fab).

This most beautiful geometer used to be the great attraction of Wicken Fen where the larvae were sometimes obtained in hundreds from the meadow rue (Thalictrum). Of recent years in spite of the continued prevalence of its foodplant, the insect has become extremely rare and at one time was thought to be extinct. Happily it has appeared often in single examples during the last decade at Woodwalton Fen and at Wicken where it was taken in 1953. It is still said to exist near Thetford, but I know of no records of late outside this restricted area.

T h e BARBERRY CARPET (Coenotephria berberata Schiff.). This double-brooded species was at one time fairly wide-spread in the south wherever the wild barberry grew. Since it was found that this plant is the host of a cereal disease, it has been eradicated Wholesale with the result that this moth has become increasingly rare and now appears to be confined to a few places mainly in Suffolk. In one small locality in this county it still occurs and was successfully bred in 1954.

The SCARCE P U G (Eupithecia extensaria Frey.). Though this most striking pug was originally discovered on the Yorkshire coast, the northern part of the Norfolk Coast is now its headquarters.

106

NOTES ON SOME LEPIDOPTERA

Here its long slender larvae can be obtained freely on the seawormwood in September, but the moth is seldom seen. It is hoped that the species was not seriously affected by the Flood of 1953.

I am much indebted to Mr. P. J. Burton for much valuable information about the above species, especially for Suffolk records.

NOTES SMALL

ON

REARING

PEARL-BORDERED

LEPIDOPTERA

FRITILLARY

(Argynnis

selene Schiff.)

See Vol. IX, Pt. I, p . l l . On 5th October, 1954, two of the larvae, which had been kept out-of-doors and which had apparently not been feeding for a few weeks, were transferred to an indoor cage where a temperature of about 70°F. was maintained by means of a 60-watt lamp, burning continuously. T h e larvae immediately began to eat. One larva pupated on 28th October and the butterfly emerged on 3rd November. Although the second larva spun up, it failed to pupate. It is interesting to note that this species very occasionally produces a second generation in the wild.

The remainder of the larvae were kept out-of-doors on growing violet plants. On 26th March there was no sign of them ; the new leaves were only just appearing. On 6th April, two larvae were seen, crawling about on the plants.

SCOTCH ARGUS (Erebia aethiops Esp.).

See Vol. VII, Pt. I I I , p. 129. In November, 1954, four young larvae were surviving from a number of ova received from Scotland in the summer.

One of these larvae was transferred to a cage indoors and kept at a temperature of about 70°F. (like the larvae of the Small Pearlbordered Fritillary). The larva fed on grass, Poa annua, pupated on 27th December, and the imago, a male, emerged on 12th January, 1955. It was, however, crippled, and the wings failed to expand. On 12th December, the remaining three larvae were placed in the forcing-cage. One died after afewdays,buttheother two throve. One butterfly emerged on 9th February but again the wings failed to expand. T h e third pupa was kept in damper conditions, though still in the cage, and on 15th February a perfect male emerged. As far as is known, this species does not produce a second generation in the year in Great Britain.

S.

BEAUFOY.