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. GHOST MOTH (_Hepialus humuli_). On Plate 157 are portraits of a male and a female of the typical form of this species (Figs. 1 [male] and 3 [female]); 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. [Illustration] 2 Pl. 158. 1-3. MAP-WINGED SWIFT. 4-6. COMMON SWIFT. 7, 8. GOLD SWIFT. [Illustration] 2 Pl. 159. 1, 1a. COMMON SWIFT: _caterpillar and chrysalis_. 2, 2a. GHOST MOTH: _caterpillar and chrysalis (enlarged)_. 3. ORANGE SWIFT: _caterpillar_. {361} 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. ORANGE SWIFT (_Hepialus sylvina_). The male of this species (Plate 157, Figs. 5. [male], 6 [female]) 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.