The Moths of the British Isles Volume I Part 14

{117} _Callunae_ was not recognized as British until the year 1847, when it was introduced as a species distinct from _quercus_. The late Richard Weaver, who gave it the English name of the "Scotch Eggar," took specimens of the moth at Rannoch in 1845, and he found caterpillars in that year, as well as in 1844 and 1846. It is now well known to occur not only in Scotland, including the Hebrides and Orkneys, but also on the moors of Northern England, and in Ireland and Wales. In North Devonshire it is found not uncommonly in the Exmoor district, and it has been recorded from various parts of the New Forest in Hants.

The egg of _callunae_ is figured on Plate 55. It appears rather polished, and in colour is pale brown mottled with darker brown. The eggs are stated to be deposited whilst the female is on the wing, and consequently they fall to the ground or are arrested in their descent by the herbage over which they are scattered.

The full-grown caterpillar of _quercus_, beneath the brownish fur with which the body is clothed, is dark brown on the back and rather violet brown on the sides; the ring divisions are velvety black; there is a white stripe along each side and below the stripe some reddish marks; the ring nearest the head is edged with reddish, and the next two rings each have two reddish centred white spots. The dull purplish brown chrysalis is enclosed in a hard oval-shaped coc.o.o.n which is spun up on or near the ground in a flimsy web among herbage, dead leaves, etc. Sometimes it is placed among the twigs of the food plant.

In Southern England the caterpillars hatch from the egg in August and usually hibernate when quite small. They feed up during the following spring and early summer, perhaps in June or July, and the moth appears in July or August. Occasionally, however, a few individuals depart from the general habit and complete their growth the same year, hibernate in the pupal stage, and produce moths the next year, possibly earlier than hibernating caterpillars. On the other hand, perhaps owing to adverse weather conditions, feeding after hibernation may be continued well on into the autumn, when the caterpillars pupate, {118} but emergence of the moth is postponed until the following year, the second after hatching from the egg.

In the case of _callunae_, at least as regards its normal habit in Scotland and southwards to the moorland districts of Yorkshire and Lancashire, the young caterpillar hibernates the first winter, feeds through the following summer, and pa.s.ses the second winter as a chrysalis, the moth emerging in the following May or June.

Generally speaking, then, it may be stated that _quercus_ has a twelve-month life cycle, whilst that of _callunae_ extends almost or quite to twenty-four months, of which at least twelve months are pa.s.sed as a caterpillar. However, as has been noted, _quercus_ sometimes pa.s.ses one winter as a caterpillar, and another as a chrysalis, thus a.s.suming the _callunae_ habit; whilst _callunae_ occasionally attains the perfect state during the summer following that in which the caterpillar left the egg.

The food plants comprise bramble, dogwood, hawthorn, heather (_Calluna_), and various low plants; it is even content with ivy.

Newman, in the _Entomologist_ for 1845, gives a life history of the Northern Eggar (_callunae_), and from this the following details are extracted. The male flies rapidly over the heather by day at the latter end of May or beginning of June; its flight is jerking or zigzag, and its object is evidently to find the female, who rarely moves until impregnation has taken place. Subsequently the female flies over the heather, dropping her eggs at random as she flies, and the eggs, having no glutinous covering, do not adhere to any object which they may accidentally touch in falling. On emergence from the egg the young caterpillar is dark ash-coloured, the divisions between the rings of the body being indicated by two minute orange streaks, each of which is accompanied by a small black spot. After the first moult the ground colour becomes more smoky, the divisions velvety black, and on each ring a triangular orange spot appears; these markings become more conspicuous later on, and by the end of October, when it hibernates, they are very distinct. It rests in a straight position, and, if disturbed, falls off its food plant, and rolls in a ring with its head slightly on one side.

[Ill.u.s.tration]

Pl. 56.

GRa.s.s EGGAR MOTH.

[Ill.u.s.tration]

Pl. 57.

GRa.s.s EGGAR.

_Eggs, natural size and enlarged; caterpillar._

{119} The habits of the Oak Eggar moths (_quercus_) are pretty much the same as those of the Northern form, except that the moths fly in July and August, and frequent hedgerows, the borders of woods, heathy commons, and cliffs and sand dunes at the seaside.

A bred female of either form will attract numerous males, and even the receptacle in which a newly emerged female has been placed is almost as effective as the lady herself. When staying at a cottage on the edge of a moor near Lynton, North Devon, some years ago, I had some pupae of the Oak Eggar. One day, late in July, quite a number of males entered the cottage and made their way to the cage in which the pupae were, and I had no difficulty in boxing several of them. The next day I put the female moth, which had emerged the previous day, into a roomy chip box, and carried it in a satchel to the moor, where it was placed on the ground, the males began to arrive soon afterwards and some fine examples were secured.

Although the female was taken on the moor only on the one occasion, that satchel continued to be an object of interest to the male Eggars for several days afterwards.

Generally distributed, and often common in some localities, throughout the British Isles. Abroad, its range extends over Europe into Asia Minor, Armenia, and Siberia.

THE GRa.s.s EGGAR (_Lasiocampa trifolii_).

This moth is usually brown in colour. The fore wings are inclined to dark reddish brown, and have a pale ochreous brown curved band or ring at the base, a slightly curved line or band of the same colour beyond the middle of the wing; central spot {120} white, finely margined in black. Except that the female is generally larger, and the cross lines usually less distinct, the s.e.xes are much alike. This brown form occurs most frequently in Britain, but in parts of the Kentish and Suss.e.x coast, and especially the Romney Marsh district, a yellowish form is obtained. In such specimens the cross lines are darker. In both forms one or both cross markings may be faint or quite absent, and even the white central dot, which varies in size and shape, may be missing. Sometimes the outer band is distinctly broad and outwardly diffuse (Plate 56).

The eggs, which appear to be laid loosely, are pale whitish brown, roughened with darker brown, and the micropylar area is purplish brown.

Some that I received on March 2, 1907, appeared to be on the point of hatching on the 5th of that month, but no larva came out, although one of the eggs was chipped at one end. It has been frequently stated that the caterpillars hatch out in the autumn and hibernate, but as has been pointed out by Tutt ("Nat. Hist. Brit. Lep.," ii. 20), the eggs of this species probably do not hatch until some time during February or March, although when kept indoors the caterpillar has emerged from the egg in January.

The full-grown caterpillar is black, velvety between the rings, covered with golden brown hair on the back and greyer hair on the sides, among which are some black ones; three interrupted whitish lines on the back; some of the hairs along the middle of the back stand erect and form a ridge, looked at from either end. Head lightish brown in colour, lined with black. Feeds in the spring months and up to June chiefly on various kinds of gra.s.s. Among many of the plants that it has been known to eat are trefoils, bird's-foot (_Ornithopus_), sea thrift (_Statice_), heather, sallow, hawthorn, sloe, plum, bramble, etc. With regard to the food, it is interesting to note that although one rearer will find that sallow is excellent for the caterpillars, another considers that sallow or hawthorn are but poor {121} subst.i.tutes for kidney-vetch (_Anthyllis vulneraria_) upon which the caterpillars were feeding when found (Plate 57).

The brownish chrysalis is enclosed in a hard but somewhat brittle, brown, oval coc.o.o.n, and when spun upon the surface of the ground, protected by an outside covering of loose silk webbing. In August and early September the moths appear. Emergence from the chrysalis usually takes place soon after midday; the males are early on the wing, and when reared in captivity they should be secured as soon as the wings are dry, or they may spoil themselves in their efforts to escape. Reared females are apt to be deformed, but for "a.s.sembling" they may probably be as useful as more perfect examples if the rearer happens to be able to exhibit the attraction in a locality for the species. Both s.e.xes have been taken at electric light.

The best known localities for the species in England are, besides those already mentioned, the sand hills on the Cheshire and Lancashire coast. It is, or has been, found also on the coast of c.u.mberland; Lyndhurst and Ringwood, in Hampshire; Isle of Purbeck, Poole, Swanage, and Bloxworth, in Dorsetshire; Devonport, Bolt Head, and Salcombe, in Devonshire; and Penzance and the Scilly Isles. Its range extends through Central and Southern Europe to Asia Minor and North Africa.

THE FOX MOTH (_Macrothylacia rubi_).

The male is reddish brown, and the female generally greyish brown, but sometimes is of a reddish grey coloration; the fore wings in both s.e.xes are crossed by two pale ochreous lines on the central area (Plate 59).

The ground colour in the male ranges in tone from foxy red to dullish red brown or to greyish red brown. The cross lines in either s.e.x may be widely apart, near together, or even united throughout their length, forming a band (var. _fasciata_, Tutt); sometimes one of the lines (var. _unilinea_, Tutt), or both lines, are absent from the fore wings, or from one of them.

{122}

The brown clouded greyish eggs are laid in batches, during June, on stems and stalks of plants, or on heather; sometimes they have been found on a fence, a rock, or a stone. The caterpillars hatch out at the end of June and through July. At first they are black, including the glossy head, and covered with long hairs which are black with some white ones amongst them; the ring divisions are pale yellow; later on they are more chocolate brown with yellow bands which, however, do not encircle the body entirely.

When full grown, in the autumn, the caterpillar is velvety black, and above this colour is most in evidence between the rings; the back is clothed with dense, short, bright reddish brown or tawny hair, and the whole body is covered with brownish hairs, varying in length, but always much longer than the tawny ones; along each side are some whitish hairs. Head blackish covered with brownish hairs. It feeds in August and onwards to October, when it seeks winter quarters, reappearing in the following spring, but not feeding again. After enjoying the sunshine whenever the opportunity offers through the early months of the year, it finally pupates in March or April.

The coc.o.o.n is a long, more or less tubular, brownish construction of silk and larval hairs. It is spun up, usually somewhat upright, low down among the food plant, or at the roots of gra.s.s, etc.; sometimes among moss, when the rounded head end can just be seen above the moss (Plate 58).

In certain localities and seasons the caterpillars have been seen in enormous numbers, but such profusion only happens now and then. In some districts they may be abundant one year, and then scarce or quite absent for several years.

When handling the larvae it will often be noted that the tips of one's fingers are thickly felted with the tawny hairs from the creature's back; if these hairs get transferred to the face or neck considerable irritation may be the result.

[Ill.u.s.tration]

Pl. 58.

FOX MOTH: _caterpillars_.

[Ill.u.s.tration]

Pl. 59.

1, 2. FOX MOTH, _males_; 3 _female_.

{123} The late Mr. Robson used to collect the caterpillars on fine days in early spring, put each caterpillar into a separate paper box about two inches square, and keep them on a shelf over the kitchen fire, where they would duly pupate. Various methods for keeping these caterpillars through the winter have been described, and all appear to have been fairly successful. The most simple would seem to be the following: Bore a number of holes in the bottom of a roomy box, and fasten wire gauze on a close fitting frame to serve as a top. Cut a tuft or two of heather to cover the floor s.p.a.ce of the box. Caterpillars collected in the autumn may be put into this receptacle and supplied with food, such as bramble or sallow, as long as they seem inclined to feed. Do not crowd too many into the box, and let it stand out in the garden, preferably on the soil.

The moths emerge in May or June. The males are very active on the wing in the afternoon sunshine, and later on, and may often be seen in numbers dashing hither and thither in an apparently erratic flight over heaths and open s.p.a.ces, in search of the females. The latter do not fly till night, and occasionally they are attracted to a bright light.

Except that it has not been noted in the Shetlands, the species occurs throughout the British Isles. Abroad its range extends over Europe, and it is found in Amurland.

THE DRINKER (_Cosmotriche potatoria_).

The male is reddish brown, more or less clouded on the forewings with ochreous; and the female is yellow, or whitish ochreous. Sometimes this colour distinction of the s.e.xes is reversed, and the males are pale whilst the females are dark. In the fens of Cambridgeshire notably, pale or yellowish males are not altogether uncommon. Such specimens would seem to accord better with the Linnean type than the more usual form indicated above. Barrett mentions, among other aberrations, male specimens from South Wales with the whole of the fore and hind wings deep rich glossy purplish chocolate. {124}

There is variation in the two whitish or silvery marks on the fore wings, the upper one is often very small, sometimes quite absent, and the lower one reduced to a crescent. The chocolate brown cross lines, of which there are usually two on the fore wings, are sometimes faint or entirely missing.

Tutt has recently named nine forms, chiefly colour aberrations, and two others were previously named. (The moth is figured on Plate 61, and the early stages on Plate 60.)

The eggs, which are white with bluish grey markings, are laid in cl.u.s.ters on gra.s.s stems, etc.

The caterpillar is slaty grey inclining to blackish; the lines on the back are formed of yellowish dots and dashes; two rows of tufts of short black hairs on the back, with longer brown hairs between; low down on the sides are s.h.a.ggy tufts of white and yellowish hairs and longer brown hairs; an erect pointed tuft of brown hair on second ring, and a similar one on ring eleven but the latter inclines backward. Head greyish, striped and lined with brown and yellowish brown, and clothed with brown hair. It feeds on coa.r.s.e gra.s.ses, including the ribbon gra.s.s grown in gardens, in August to September or October.

In the latter month it goes into hibernation, being then but little over an inch in length. About April it resumes feeding and becomes full grown in June or thereabouts. The long yellowish or whitish brown coc.o.o.n in which it changes to a brown chrysalis is more or less pointed at the lower end, and generally attached to a culm of gra.s.s or a reed. A showery season seems to suit these caterpillars better than a hot, dry one. The partiality of the caterpillar for a drop of dew, mountain or otherwise, has frequently been noted. The old English name of The Drinker Caterpillar (1682) is therefore not only an appropriate one but shows that this larval habit was observed even at that early date. The specific name _potatoria_ given to the moth by Linne is of similar significance.

[Ill.u.s.tration]

Pl. 60.

DRINKER MOTH.

_Eggs, natural size and enlarged; caterpillars and coc.o.o.n._

[Ill.u.s.tration]