A Review of Lepidoptera in Great Britain during 1965

A REVIEW OF LEPIDOPTERA IN GREAT BRITAIN DÜRING 1965 B A R O N DE

WORMS

THE promising and mild Start to the year which brought out the early species of the geometers at their normal period during February, was given quite a setback by a very bleak period which ushered in the month of March with a heavy snowfall. However, a real touch of spring began in the middle of that month when the Yellow Horned (Achlya flavicornis, Linn.) began to appear together with the usual noctuid moths frequenting the sallow blossom which was at its best in the last week in March. It was at this time that the hibernated butterflies were to be seen in unusual abundance, especially the Brimstone (Gonepteryx rhamni, Linn.) and the Peacock (Vanessa io, Linn.). On the last day of March the Small Tortoiseshell (Aglais urticae, Linn.) was swarming at Oxford in a shade temperature of 73°F. The season continued on an average scale during April which was for the most part mild with the spring butterflies out at about their normal time of emergence. The Orange-tip (Anthocharis cardamines, Linn.) was on the wing by the third week of the month.

The period which the appearance of the first of the Notodonts, the Scarce Prominent (Odontosia carmelita, Esp.) A very warm spell in the first week of May enticed out the two smaller Fritillaries in fair numbers, the Pearl-bordered (Clossiana euphrosyne, Linn.) was followed by the Small Pearl-bordered (C. selene, Schiff.) about the middle of May. It was at this date that a most remarkable capture was made in a house at Weston-super-Mare, that of a Small Läppet (Epicnaptera ilicifolia, Linn.), a moth which has not been seen in Britain for a great many years. About a Century ago it inhabited the moors round Sheffield and Cannock Chase.

The source of this specimen may well have been Exmoor where there were reports in the last Century of the finding of its larva on bilberry, its chief food plant. Who knows whether it may not still lurk in this vast and almost untouched region ?

During the last ten days of May there occurred what would appear to be quite a big immigration of several well-known species of moths of which the most noteworthy was the Striped Hawk (Celerio livornica, Esp.). There were records of this fine insect from as wide a front as the Gower Peninsula in Wales to Tolworth just south of London. A number too of the Small Mottled Willow (Laphygma exigua, Hübn.) turned up at the same period and in similar areas together with a few of the small geometer, the Vestal (Rhodometra sacraria, Linn.). In early June which was mainly fine and warm the Marsh Moth (Hydrillulapalustris, Hübn.) reappeared in its restricted haunts in the Fens, but little eise of outstanding interest seems to have been noted tili towards the end of June when

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another example of that small noctuid moth, the Pretty Marbled (Jaspidia deceptoria, Scop.) was obtained near Rye in Sussex where it was last seen in 1957. It is rather a mystery whether this insect may be breeding in this country or if it may be a regulär migrant.

July, however, provided some most remarkable captures and also saw an abundance of several rather localised species. One of these was the fine noctuid moth Ashworth's Rustic (Amathes ashivorthii, Doubleday) which swarmed during the first days of July among the mountainous areas of North Wales. T h e small Snout moth, the Olive Crescent (Trisateles emortualis, Schiff.) was again taken in some of the beech woods of the Chilterns where it appears to be a resident. It was in the middle of this month that a new moth was added to the British list, taken on the Suffolk coast at Thorpeness. It was one of a small group of moths known as the Fanfoots because of the peculiar prominences on their forelegs. This new insect was identified as (Zanclognatha tarsicrinalis, Knoch.) which is somewhat similar to the Common Fanfoot (Z. tarsipennalis, Treits). This apparently new arrival requires an expert eye to distinguish it from its very widespread relative. It is hoped it may establish itself as a resident in due course. At about this period specimens were obtained on the Norfolk Broads of Plusia gracialis, Lempke, a species very similar to a North American insect which seems always to have been with us, but was only quite recently separated on its genitalia structure from the Gold Spot (Plusia festucae, Linn.). It differs also by its slightly smaller size and shape together with a characteristically brighter colour and somewhat less acute cross-lines. This newly recognised species has been found to occur mostly in reedy areas in many parts of the country as far north as the Lake District. July saw a spate of some of the larger Fritillary butterflies, in particular the Dark Green {Argynnis aglaia, Linn.), mainly in downland regions.

The Chalk-hill Blue (Lysandra coridon, Poda) appeared at the end of July in better numbers than for a good many years in certain of its now very restricted localities, but August which opened with a fine spell did not produce the swarm of the Vanessids butterflies which had occurred a year previously. In fact the Small Tortoiseshell (Aglais urticae, Linn.) and the Red Admiral (Pyrameis atalanta, Linn.) were both extremely scarce and sporadic as also was the Painted Lady (Pyrameis cardui, Linn.) of which only a few were recorded for the whole of the British Isles. However, early August was not without its surprises. An unexpected visitor to Folkestone at this period was that tiny noctuid moth, the Silver Bar (Eustrotia olivana, Schiff.), far from its normal fen haunts and doubtless a migrant from abroad. Likewise must have been the white example f. arenaria of the Speckled Footman (iCoscinia cribraria, Linn.) which was taken on the Suffolk coast, a region where this arctiid moth has never before been seen, its only British habitat being the New Forest area.

212 Transactions of the Suffolk Naturalist*',

Vol. 13, Part 4

But by far the most sensational discovery of the year and even of the Century was the chance capture of a specimen of the Rosy Marsh moth (Coenophila subrosea, Stephens) in a remote part of Wales during the first half of August, the normal time for its appearance abroad. This fine noctuid had not been seen anywhere in the British Isles for some 120 years, since its only apparent habitat was a very fenny and swampy tract in Huntingdonshire, when Yaxley and Whittlesey meres were still in being. It seems to have died out from these parts in the 1840's. It now remains to be seen whether this insect has always been with us in some secluded area where no naturalist with a net has penetrated before.

As usual late August and early September provided a certain number of both regulär and rare migrants, such as the Death's Head (Acherontia atropos, Linn.) and the Convolvulus Hawk {Herse convolvuli, Linn.). Both these well-known arrivals from abroad were seen only in comparatively small numbers and very few records of them were made. Several of the Ni Moth (Plusia ni, Linn.), however, were noted in the first part of September including one in the extreme west of Ireland where it had only been seen once since the last War. But it was the remarkably fine October, really the best month of the whole year, which accounted for several very exceptional captures and also for quite a spate of autumn moths, especially that very local species, the Dotted Chestnut (Dasycampa rubiginea, Fab.). This was not perhaps surprising since it has seldom been so plentiful as in the previous spring after hibernation. Among the rarities recorded in the autumn, mainly in October were two of the Clifden Nonpareil (Catocala fraxini, Linn.), that magnificent insect, the biggest of the Noctuid moths of which one was taken at Reigate and another at Brockenhurst in the New Forest. There is no evidence that they bred in these districts as they did for many years in East Kent just after the last War. Also in late September a Golden Twinspot {Plusia chalcites, Esp.) was taken in the Isle of Wight, while the Blakc-streaked Pug (Kupithecia pgoeniceata, Rambur) turned up at Southsea, its most easterly ränge since its original discovery near Land's End in 1959.

Yet another most striking feature during the late summer was the remarkable abundance of the Stout Dart (Spaelotis ravida, Hübn.), mainly in the Eastern Counties and especially in Cambridgeshire and Suffolk. On 7th September no less than forty-eight of this large but generally scarce noctuid moth were recorded for a Single night in a moth-trap on the outskirts of Cambridge, while this species appeared in smaller numbers over a few weeks in several areas of these two counties. It is likely that quite a proportion of these moths were part of a large immigration, as this species is noted for its sporadic appearances in large numbers, usually at long intervals.

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Well on into the autumn a further noteworthy capture in the New Forest was a single example of Blair's Mocha (Cosymbia puppillaria, Hiibn.), right at the end of October, very late for this insect which seems to have a precarious foothold in several widely separated regions in the south of England. Yet a further surprising visitor to the New Forest in early November was a Cosmopolitan Wainscot (Leucania loreyi, Dup.), a very infrequent immigrant of which possibly only one other has been recorded from Hampshire.

The middle of October saw a veritable invasion on a small scale of some of the more regulär migrants which included the Small Mottled Willow (Laphygma exigua, Hübn.), also further Vestals (Rhodometra sacraria, Linn.) together with the Gern (Nycterosia obstipata, Fab.) and the Scarce Olive-tree Pearl (Palpita unionalis, Hübn.). At that period too, a couple of the still rarer Pyrale, the Yellow-underwinged Pearl (Uresiphita polygonalis, Schiff.) were taken at Freshwater in the Isle of Wight. This capture virtually brought to an end an interesting, if not a very prolific year for British Lepidoptera.