Volume I Part 14 (1/2)
{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 Devons.h.i.+re 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 Yorks.h.i.+re and Lancas.h.i.+re, 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 Ches.h.i.+re and Lancas.h.i.+re coast. It is, or has been, found also on the coast of c.u.mberland; Lyndhurst and Ringwood, in Hamps.h.i.+re; Isle of Purbeck, Poole, Swanage, and Bloxworth, in Dorsets.h.i.+re; Devonport, Bolt Head, and Salcombe, in Devons.h.i.+re; 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.