The Moths of the British Isles Second Series/Chapter 14
SESIIDÆ.
This family—the Ægeriadæ of some authors—has over one hundred Palæarctic species assigned to it; these are distributed among five genera, two of which are not represented in Britain. Fourteen species are found in the British Isles, but to obtain fine specimens of most of them the mature caterpillars or the chrysalids will have to be collected and the moths reared. All species emerge from the chrysalis early in the forenoon, and then only under the influence of sunshine.
The caterpillars are somewhat maggot-like, and live in stems, branches, and roots of trees and shrubs; or in the crowns and roots of low-growing plants. The majority, possibly all, are nearly two years in arriving at full growth.
Hornet Moth (Trochilium apiformis).
As indicated by the English name this moth, and also that next to be mentioned, are very like the hornet (Vespa crabro). On turning to Plate 154, Fig. 1, it will be seen that this species has a yellow head and patches of yellow on the shoulders; these characters at once separate it from T. crabroniformis.
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The caterpillar is yellowish white, with a red brown head, and a yellow plate on the first ring of the body. It feeds on the roots and lower portion of the trunks of poplar. The brown shining chrysalis is enclosed in a cocoon of wood scrapings woven together with silk. The moth is out in May and June; and has been found, newly emerged, sitting on stems of poplar in the morning.
The eastern counties of England appear to be most favoured by this species, but it also occurs northwards to Yorkshire, southwards to Devonshire, and a specimen has been recorded from Rhyl, North Wales. In Scotland, it has been reported from some localities in the south; Kane states that he has reason to believe that the species occurs in the northern half of Ireland, and that he found caterpillars plentiful in young poplars growing in a marsh near the city of Waterford.
Lunar Hornet (Trochilium crabroniformis).
Another hornet-like moth, best distinguished from that just mentioned by the yellow collar behind the black head (Plate 154, Fig. 7 ♀). The male is rather smaller, but otherwise similar.
The caterpillar is yellowish white, with dark brownish head, and a blackish edged yellow plate on the first ring of the body. It feeds in stems of sallow, willow, and poplar. In late June and through July the moth is on the wing, and may occasionally be seen at rest on leaves or stems of sallow, etc.
The species, known also as bembeciformis, Hübner, is generally distributed throughout England, Wales, and Ireland; in Scotland its range extends into Perthshire.
Abroad it seems pretty much confined to Holland, Northern and Central Germany, Austria, and Bohemia.
Clear Underwing (Sciapteron tabaniformis).
This species is the Trochelium vespiforme of some British authors, and the Ægeria asiliformis of Stephens and others.
Another English name for it is the Dusky Clearwing, and this refers to the cloudy fore wings.
Stephens, writing of it in 1828, remarks: "Occasionally taken on poplars, near London, in June. I have obtained it from the neighbourhood of Bexley, and from Birchwood; but it is doubtless a rare species, and exists in few collections: of the male, I have hitherto seen but two specimens, one of which I possess." Both places mentioned by Stephens are in Kent, and one or two specimens of the species have since been reported from Ashford in the same county. The late Henry Doubleday took specimens at Epping, Essex. Colney Hatch Wood in Middlesex has also been given as a locality in the past; more recently two specimens have been noted from Chiswick. The example shown on Plate 154, Fig. 4, is of continental origin.
The caterpillar lives under the bark of poplar trunks, and the moth flies in June and July.
Welsh Clearwing (Sesia scoliæformis).
As a British species this insect was first noted from Llangollen, in North Wales, somewhere about fifty years ago. In 1867 it was found to inhabit birch woods in the Rannoch district of Scotland, and later on its presence was detected in Sutherlandshire. It has been recorded from Hereford; one example was reported from Wiltshire in 1857; and two from Delamere Forest, Cheshire (1901 and 1905). Kane (Catalogue of the Lepidoptera of Ireland) states that moths have been taken at Killarney, and caterpillars obtained in the same district, and also at Kenmare.
The caterpillar (Plate 156, Fig. 3; after Hofmann) feeds on the inner layer of bark of large birch trees, and is full grown about May. It turns to a dark brownish chrysalis, in a cocoon formed close up to the bark, which thinly covers the outer end of the burrow. The moth flies in June or sometimes July. It is of comparatively large size, and may be distinguished from the next species by the yellow belts on its body, and the chestnut coloured tuft at the tail. (Plate 154, Fig. 2.)
White-barred Clearwing (Sesia spheciformis).
Although generally smaller, some specimens run very close to the last species in size. It may be distinguished by the single belt on the body and the black tail (Plate 154, Fig. 3). One of the best known localities for the species in England is Tilgate Forest, in Sussex; but it also occurs in Hampshire (Basingstoke), Hereford (Tarrington), Worcestershire (Wyre Forest), Staffordshire (Burnt Wood), Cheshire (one, Delamere Forest, 1901), Denbighshire (Llangollen), Lancashire (Chat Moss), and Yorkshire (Bishop's Wood, 1894).
The caterpillar feeds in stems of alder, and is full grown in May of the third year after hatching from the egg. It is said that the chrysalis may sometimes be found by bending and twisting the stems of alder, so as to cause the thin skin of bark over the exit hole of the burrow to crack, and so disclose its whereabouts. The burrow is generally low down the stem. The moth is out in June and early July, and is sometimes to be seen on sunny mornings at rest on alder leaves, or flying over and around the bushes.
Orange-tailed Clearwing (Sesia andrenæformis).
Although known to be a British species since 1829, when a specimen was taken in a wood near Greenhithe, Kent, this insect continued to be very rare until quite recently. For a long time the caterpillar was supposed to feed in the stems of dogwood, but it is now known to live in the stems of the wayfaring tree (Viburnum lantana), and several specimens of the moth have been reared during the past year or two. Unfortunately the caterpillar is much infested by parasites, and comparatively few escape attack. Notes on the life history of this moth, by the Hon. N. Charles Rothschild, Mr. Eustace Bankes, and Dr. Chapman, are published in the Transactions of the Entomological Society of London for 1906 (Part IV., pp. 471-482).
Most of the known localities for the species are in Kent, but it has also been found in Surrey, Dorset, Gloucester, Hertfordshire (Tring district), and Northamptonshire (Oundle). Possibly it will be discovered in other parts of the country. I am indebted to Mr. L. W. Newman, of Bexley, for the specimen figured on Plate 1, Fig. 1. For the caterpillar mine in stem of Viburnum (Plate 156, Figs. 2, 2a) my thanks are due to Mr. Rayward, who kindly sent me a living pupa, from which the moth duly emerged, but, I regret to add, escaped from the box in which the stick containing the chrysalis was kept.
Newman, in 1833, described this species as Trochilium allantiformis, and in 1842 it was figured by Westwood and Humphreys as T. andreniforme. It is distinguished from Sesia tipuliformis by the two yellow belts of the body (the first sometimes indistinct) and the orange-yellow tuft in the blue-black tail; on the underside of the body there is a broad yellow band on the fourth ring, sometimes extending to the fifth and sixth.
Currant Clearwing (Sesia tipuliformis).
In this species the body is narrowly belted with yellow, usually four belts in the male and three in the female; the tail tuft is black in both sexes. The outer marginal border of the fore wings has a bronzy tinge, due to orange patches between the veins. (Plate 154, Figs. 5 ♂, 6 ♀.)
The caterpillar lives in the stems and shoots of black and red currant bushes; it feeds on the pith, and works its way downwards. When full grown, about May, it gnaws an outlet to the side of the stem, but does not penetrate the outer skin, although it reduces this to a very thin layer, through which the reddish brown chrysalis is able to force itself when the moth is ready to emerge. A figure of the caterpillar will be found on Plate 156, Fig. 1; the chrysalis protruding from currant stem (Fig. 1a) is from a photo by Mr. H. Main. In June or July, the moths are not infrequently seen on leaves of shrubs in gardens where there are currant bushes in or around such gardens, but the foliage of the food plant is a favourite resting place.
Generally distributed throughout England, the range extending into Wales, and South Scotland, but is apparently rare in these countries and also in some of the northern counties of England. Kane states that the species is common near Dublin, and is probably widely distributed in Ireland.
This species seems to have been introduced into North America, where its caterpillar is known as the "currant borer," and, as in England, is regarded with little favour by bush-fruit growers.
Yellow-legged Clearwing (Sesia vespiformis).
This species (Plate 155, Fig. 1), known also as asiliformis, Rottemburg (1775), and cynipiformis, Esper (1782), is now held to be correctly referred to vespiformis, Linnæus (1761). The crossbar of the fore wings is orange red in both sexes; the body of the male has two more or less united yellow spots at the junction with the thorax, four yellow belts, and the tail tuft is black above, mixed with yellow below; in the female the body belts are usually one less than in the male, the yellow spots at the junction are generally run together, and the tail tuft is almost wholly yellow. As indicated by the English name, the legs are largely yellow in both sexes.
The caterpillar feeds on the inner bark of oak trees, is full grown in May or June, and turns to a brownish chrysalis in a cell formed in the bark. A well-known locality for this moth, which is out in July and early August, is Hyde Park, London. It is also found in woods or oak-timbered parks in Kent (Tunbridge Wells), Surrey, Sussex (Abbot's Wood, Tilgate, etc.), Dorset (Glanvilles Wootton, etc.), Devon (Devonport, Plymouth, Topsham, etc.), Essex (Epping), Suffolk, Oxfordshire, Gloucestershire, Leicestershire, Staffordshire, and Yorkshire (Doncaster).
Red-belted Clearwing (Sesia myopæformis).
One example of each sex is shown on Plate 155, where Fig. 2 represents the male and Fig. 3 the female; both have a single belt on the body; as a rule, the belt is red, but occasionally it inclines to orange or yellow.
The caterpillar feeds on the inner bark of the trunks or boughs of apple, and sometimes pear, trees. It is nearly two years in maturing, but is full grown about June. The moth is out during the summer months, and is to be seen early on sunny mornings, newly emerged from the chrysalis on the trunks of the trees in which the caterpillar lives; the chrysalis skins will also be noted at the same time, sticking out from holes in the bark. Later in the day it sits on leaves, etc., after its flights, and I have even found it occasionally on a gravel path, and once on the pavement of a road in North-west London.
The species seems to be most frequent in gardens and orchards around London, but it has been recorded from as far north as Lancashire and Yorkshire; it is probably widely distributed over England. The Irish localities, mentioned by Kane, are Dublin, Cork, Killarney, and Clonbrock.
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Large Red-belted Clearwing (Sesia culiciformis).
This species (Plate 155, Fig. 4) is very similar to the last, but it is larger, and the fore wings are dusted with reddish scales towards the base, sometimes also along the inner margin. The belt on the body is generally red, not infrequently with an orange tinge, but it is sometimes yellow or far more rarely white.
The caterpillar, which is full grown in May, feeds on the inner bark of birch trees and bushes, apparently preferring the stumps left in the ground where stems have been cut down. It is not difficult to find, but as it is about two years in this stage it should not be taken until nearly or quite full grown, and it is safer to leave it until it has entered the chrysalis state. The moth is out in June, or sometimes at the end of May; it flies over birch and rests on leaves, and has been known to visit flowers of the wood spurge and the rhododendron.
Kent and Sussex appear to be the counties most favoured by this species, but it occurs in most of the other English counties in which there are birch woods, certainly up to Yorkshire, and probably further north, as it is found in Scotland (Clydesdale, Perthshire, and Aberdeen). The Irish localities are Killarney, Ballinasloe, and Derry.
Red-tipped Clearwing (Sesia formicæformis).
This is another red-belted species, but it differs from either of the two immediately preceding in having the fore wings tipped with red. (Plate 155, Fig. 5.)
The caterpillar feeds in the twigs and stumps of osier (Salix viminalis), sometimes called "withe"; it is full grown about June. (Plate 156, Fig. 2; after Hofmann.) The moth is out in July and August; it is partial to marshes and other wet spots, and is fond of a leaf as a resting place. Like the rest of its kind, it is very alert, and skips off quickly on one's approach. Probably the species is more widely distributed in England, but from the records, it only appears to have been noted from Kent, Hampshire, Somersetshire, Gloucestershire, Herefordshire, Derbyshire, Yorkshire, Norfolk, Suffolk, Cambridgeshire, and Essex.
Six-belted Clearwing (Sesia ichneumoniformis).
The inner and outer margins of the fore wings are tinged with orange, and there is an orange mark on the outer edge of the cross bar; the body of the male has seven yellow belts, and that of the female one less. (Plate 155, Fig. 6.)
The caterpillar feeds in the roots of bird's-foot trefoil (Lotus corniculatus), and kidney vetch (Anthyllis vulneraria); it is full grown about June. July and August are the months for the moth, and its haunts are on chalk downs, and on banks by the sea; it seems partial to the edges of chalk pits, sloping banks, and broken ground of undercliffs, etc. In such places it is to be seen on the wing in the early evening, and, I believe, in the early morning also. It has frequently been obtained by sweeping the net over herbage in the vicinity of the food plants.
Mr. W. H. Flint records (1902) the species from the Forest of Dean district, where, he states, he could easily have captured two dozen a day, as they flew over trefoils, etc.
The species occurs in most of the southern seaboard counties of England, from Kent to Cornwall and including the Isle of Wight; Surrey, Bucks., Essex, and other eastern counties, including Cambridge; and it has been recorded from Yorkshire. On the western side of the country it is found in Somerset, Gloucester, Hereford, Worcester, Staffordshire, and in South Wales.
Thrift Clearwing (Sesia muscæformis).
This is our smallest species of the genus, and it is further distinguished by narrow clear spaces on the blackish, or bronzy, fore wings, three whitish bands on the body, and traces of a whitish line along the middle of the back. (Plate 155, Fig. 7.)
The caterpillar feeds on the roots of thrift or sea-pink (Armeria vulgaris), and is full grown about June. The moth is out in June and July, and seems to have a liking for the flowers of thyme.
This species (also known as philanthiformis, Laspeyres) frequents rocky places on the coasts of Devon (Torquay, Lynmouth, etc.), Cornwall, Wales; Isle of Man; Scotland (Aberdeenshire); and Ireland (Saltee Islands, Wexford, and Seven Heads, Cork. Gregson recorded it from Howth).
Fiery Clearwing (Sesia chrysidiformis).
The orange red colour on the fore wings, and of the tail tuft, at once distinguish this species (Plate 155, Figs. 8 ♂, 9 ♀) from either of its British allies. The blackish body has two pale-yellow belts, but in the male the lower one is often double. As a rule, the body of the female is stouter than that of the male, but the bodies of some males appear quite as thick as those of the females, and the true sex is only disclosed by the ciliated antennæ, which is a character of the male alone.
The caterpillar feeds on the roots of dock and sorrel, and it is full grown about May. In June and July the moth is on the wing and flies in the sunshine, about noon, over the food plants.
The species occurs not uncommonly in the Warren at Folkestone, Kent. This locality, well known to entomologists, is a long stretch of rough broken ground lying between the railway and the sea; and is probably the only spot in the British Isles where the Fiery Clearwing is almost certain to be found, either in its early or its perfect stage, at the proper season. The moth has been recorded from Eastbourne, Sussex (1874), and from the Forest of Dean, Gloucestershire (1902).