The Moths of the British Isles Second Series/Chapter 15

Of the twenty-two Palæarctic species belonging to this family, nine appear to occur in Europe, and the range of five of these extends to the British Isles.

In some of the more recent systems of classification, this family is relegated to almost the bottom of the scheme, and therefore occupies a much lower place than do the bulk of the families comprised in the old style "Micro-Lepidoptera." As, however, these insects, commonly called "Swifts," have long received the attention of collectors, and in collections usually occupy a position among the so-called "Bombyces," they have been included in the present volume.

On Plate 157 are portraits of a male and a female of the typical form of this species (Figs. 1 ♂ and 3 ♀); and two male examples (Figs. 2 and 4) of the Shetland race var. thulensis, Newman, better known perhaps as hethlandica, Staudinger, but the former is the older name. It will be noted that in the ordinary form the male has white wings, and that the female has yellowish fore wings marked with orange, and smoky hind wings. The Shetland male, represented by Fig. 2, has the fore wings whitish buff in colour with brownish markings similar in pattern to those of an ordinary female; the hind wings are blackish. The second example of thulensis (Fig. 4) is somewhat similar in appearance to a typical female. In other male specimens of this insular race the wings are pretty much of the typical colour, but the markings on the front pair are reduced both in number and size. Mr. H. McArthur, who has collected a good deal in the Shetland Isles, states that in Unst, the most northern island of the group, more or less typical humuli were found on the cliffs facing south-east, whilst the majority of the specimens obtained in boggy meadows, etc., were of the thulensis form.

The caterpillar feeds on the roots of plants, such as burdock, dandelion, dead-nettle, etc. It is full grown in May, and the moth is out in June and July. (Plate 159, Fig. 2; after Hofmann.) The males may be seen in the evening, sometimes in numbers in grassy places, swaying themselves to and fro without making progress, and appearing as though they dangled from the end of an invisible thread; the female flies straight, and, as a rule, in the direction of one or other of the pendulous males.

The species is generally distributed over the British Isles.

The male of this species (Plate 157, Figs. 5. ♂, 6 ♀) usually some shade of orange brown, with greyish-edged white markings on the fore wings. Sometimes the female is orange brown, but more often it is some shade of grey brown.

The caterpillar (Plate 159, Fig. 3; after Hofmann) feeds on the roots of dock, bracken, viper's bugloss, etc., and is full grown about July. In late July and in August the moth may be seen in the early evening flying among bracken, and not infrequently around trees fairly high up. Occasionally, specimens are seen in the daytime on tree-trunks, fences, etc. At one time this species was known in the vernacular as "The Tawny and Brown Swift"; it is also "The Orange or Evening Swift" of Harris (1778) and the "Wood Swift" of Newman. It is common in many southern and eastern parts, but widely distributed over England, Wales, and Scotland to Moray. Only doubtfully recorded from Ireland.

At one time this species (the velleda of Hübner) was known as the "Northern Swift," but as it is plentiful in North Devonshire and Somersetshire, and occurs less commonly in other southern English counties, that name is hardly suitable. Haworth's English name for it—"The Beautiful Swift"—does not quite meet the case, because, although the insect is prettily marked, it is scarcely beautiful. We have then to fall back on Donovan's Map-winged Swift as a popular name, and this seems a fairly apt one, as the markings on the fore wings are somewhat map-like in pattern, especially in the more typical specimens.

There is much variation in colour and in marking; some examples, chiefly those from Shetland, are prettily variegated. A uniform reddish-brown variety, ab. gallicus, Lederer, is depicted on Plate 158, Fig. 3; and a more or less typical specimen of each sex is shown on the same plate (Figs. 1 ♂, 2 ♀).

The caterpillar is ochreous white, with orange-brown plates, and rather paler raised dots; head, reddish brown, and spiracles black. It feeds on the roots of the bracken, and is full grown about May. The moth is out in June and July, and flies, in the gloaming, on hill slopes, heaths, and the edges of mosses and woods; it seems to be more active than either of the other British "Swifts"; at all events, I have always found it less easy to capture with the net.

The species is pretty generally distributed throughout the British Isles.

Three examples of this species are shown on Plate 158. Fig. 4 is a typical male, Fig. 5 a whitish suffused variety, and Fig. 6 is a female. The latter sex is generally devoid of marking, and in the male the stripes and dashes are far more conspicuous in some specimens than in others.

The glossy whitish caterpillar has a brown head; the plate on the first ring of the body is brownish, and the raised dots are pretty much of the same colour. It feeds on the roots of grass and other plants, and is full grown about April. A figure of the caterpillar, from a drawing in colour by Mr. A. Sich, and a photo of the pupa by Mr. H. Main, are shown on Plate 159, Figs. 1 and 1a; the latter is twice natural size.

The moth is out in June, or sometimes late May, and occasional specimens have been noted in September. It is more frequently seen at rest, on fences, etc., than either of the other species of the genus; but towards dusk it is on the wing, and may then be observed in large numbers careering over grass meadows or along stretches of green turf by the wayside.

Generally distributed, and often abundant, throughout the United Kingdom; and it occurs in Monaghan, Mayo, Galway, and Kerry, in Ireland.

Both sexes of this species are shown on Plate 158, where Fig. 7 represents the golden-marked male, and Fig. 8 the more dingy, dull, purplish-grey striped female. There is variation in number and in size of the markings on the fore wings of the male, and occasionally the hind wings in this sex are adorned with golden spangles on the outer area.

The pale greyish brown caterpillar has glossy darker brown plates on rings 1-3, and the raised dots and the spiracles are black. It feeds on the roots of bracken, and is full grown about May. Buckler states that at first it burrows in the root, hibernates when small, resumes feeding in April, attains full growth before winter, and hibernates in the earth for a second time; in the spring of the second year it gnaws cavities in the young shoots of the bracken, and apparently drinks the flowing sap.

The moth is out in June. The males fly at dusk, something in the manner of humuli, over and among the bracken; but the females fly in a more or less direct line. An odour given off by the males of this species has been likened to that of the pine apple; whilst the "scent" of the Ghost Moth is said to be more of the billy-goat character.

In most woody localities, where the bracken flourishes, this species will be found throughout England, Wales, Scotland to Aberdeen and the Hebrides, and Ireland.