The Moths of the British Isles/Chapter 9

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DREPANIDÆ.

The British species belonging to this family, with one exception, have the tips of the fore wings pointed and curved downwards, forming a sort of hook, hence the English name Hook-tips. The exception is Cilix spinula, a round winged moth, not at all like other members of the family, but its caterpillar is very like others of the group.

The bristle and catch arrangement for locking the wings is present in all the species, but the tongue or proboscis is absent, or practically so. The caterpillars are not furnished with anal [ 133 ] claspers, therefore have only fourteen legs, that is, six true legs and eight false legs (pro-legs). The last ring of the body is more or less tapered, sometimes terminating in a point; the back is roughened with raised spots and warts, or humped. They feed on the leaves of trees and bushes, usually exposed, and they pupate in a silken cocoon, spun up between leaves, or in a folded leaf, of the food plant.

Of the eleven species occurring in the Palæarctic Region, seven are European, and six of these are found in the British Isles.

The Pebble Hook-tip (Drepana falcataria).

The fore wings are brown, whity brown, or whitish; the central area is crossed by three blackish wavy lines, a blackish blotch in the third line and two blackish dots between it and the second line; beyond there is a dark brown, or reddish-brown curved line from the tip of the wing to the inner margin. Hind wings similar in colour to the fore wings, but paler on the front area; crossed by five wavy dusky lines, sometimes not well marked except on the inner margin; generally, there is a black central dot. The paler forms have a dusky shading on each side of the curved line on the fore wings.

The egg is yellow freckled with orange, chiefly at one end. Caterpillar green, the back reddish-brown, except towards the black-marked yellowish head; two conspicuous warts on rings two to five, and less noticeable raised spots on the other rings, all bearing hairs. In a younger stage it is blackish, with white marks on the fourth and seventh rings; later it becomes greenish below, and the markings on the back of rings four, seven, eight, and ten are whitish or creamy. Until nearly full grown it usually lives on the underside of a leaf, the edges of which are turned over and held down by silken threads; sometimes it may be seen on the upper side of a leaf under a slight web. It feeds [ 134 ] chiefly on birch, but is occasionally found on alder, in June and July, and in September and October, and may be obtained by searching or by beating, but the former, although perhaps slower, is much the better method. The moth is shown on Plate 68, and the early stages on Plate 69.

The species is widely distributed, and seems to occur, sometimes commonly, wherever there are birches, especially of bush-like growth, in most English counties and also in Scotland. In Ireland it appears to be somewhat local and scarce.

The Scarce Hook-tip (Drepana harpagula).

The general colour of this species is brownish; the fore wings are slightly tinged with ochreous and speckled with minute violet-tinged silvery scales; between the first and second brown lines there is an irregular ochreous brown mark enclosing yellowish spots; the violet-tinted glistening scales are most in evidence on both sides of the black mark before the outer margin. Hind wings similar in colour to the fore wings; crossed by two brown lines, the second with an ochreous brown blotch above it (Plate 68).

Caterpillar, yellow freckled with brown; clouded with brown on first three rings; a reddish brown irregular stripe runs along the sides and upwards towards middle of the back on rings five, six, eight, and nine; a double-pointed hump on the back of ring three, the points tipped with yellow. Head notched on the crown, dotted and clouded with brown. It feeds on the small-leaved lime (Tilia parvifolia), and may be found from July to September and even later. I have not seen a living caterpillar of this species; the above short description has been drawn from an inflated skin (Plate 69).

The only British locality for this species is the Leigh Woods near Bristol, where it was first met with in 1837. It is, however, very rare and difficult to obtain. Abroad it ranges through Central Europe to Livonia, Southern Sweden, and to Northern Italy. On the Continent the caterpillar feeds on the foliage of other trees than lime, and there are two broods in the year.

Moths of the British Isles Plate068.jpg


Pl. 68.
1. Scarce Hook-tip, male; 2 female.
3, 5, 6. Pebble Hook-tip, males; 4, 7 females.

Moths of the British Isles Plate069.jpg


Pl. 69.
1, 1a, 1b. Scalloped Hook-tip: eggs, caterpillar and chrysalis.
2, 2a, 2b. Pebble Hook-tip: caterpillar, chrysalis and cocoon.
3. Scarce Hook-tip: caterpillar.

[ 135 ]

The Oak Hook-tip (Drepana binaria).

The male is of an ochreous-tinged brown coloration; all the wings are crossed by two slender deep ochreous lines, and have two obliquely set, almost central, black dots; outer margin of fore wings often blackish, marked towards the tip; the hind wings are deep ochreous on the front marginal area. Fore wings of the female paler, and the hind wings ochreous yellow; the cross lines on the latter often lost in the ground colour (Plate 71).

In freshly emerged male specimens the brown is sometimes purplish tinged, and in some examples of the same sex the hind wings may be described as ochreous, with brown bands. The female occasionally has the fore wings tinged with greyish, and the hind wings are sometimes banded with brown, especially on the inner marginal area.

The caterpillar is ochreous brown with a double-pointed hump on ring three, a yellowish diamond on the back of rings five to ten; the front and hind rings are brown, more or less tinged with purple; yellowish lines, shaded below with purplish brown, on the sides meet on the back and form an edging to the diamond mark. The figure on Plate 70 shows the caterpillar in its usual resting attitude. It feeds on oak.

A widely distributed species in the southern half of England, but not especially abundant in any locality, and not known to occur north of Lincoln.

The Barred Hook-tip (Drepana cultraria).

Fore wings pale fulvous or ochreous brown, with two paler cross-lines on all the wings, space enclosed by the lines darker brown; a black or blackish central dot, and before the brownish [ 136 ] outer margin there is a pale line ending on the tip of the wing. The hind wings have an obscure dusky central dot placed in the upper edge of the band, and usually there are two brownish bands on the outer marginal area, but these do not extend to the front margin. Except that the female is generally larger, and the antennæ are simple, the sexes are much alike (Plate 71).

This species is best distinguished from binaria by the dark bands, and the straighter second line. The central dots are less trustworthy characters, because summer specimens of the present species often have two of these spots on the fore wings (var. æstiva, Spr.), and in occasional examples of binaria the lower central spot of the hind wings is absent. As a rule, however, the central dots are more conspicuous in binaria than in cultraria. The egg is yellowish, tinged with reddish at the ends and along the sides. The caterpillar is somewhat similar to that of the last species, but the hump on ring three is smaller, and the side lines and diamond mark are whiter. It may be found in June and July, and again in September, and even in October in some years. It feeds on beech (Plate 70).

This species is found where beech trees occur, preferably on a chalky soil, in the counties of England from Norfolk southwards. The male may often be seen in May, flying around the beech trees or neighbouring bushes, in the sunshine; or both sexes may be caused to leave their resting places among the foliage by tapping the boughs.

Its range extends through Central Europe to Asia Minor.

The Scalloped Hook-tip (Drepana lacertinaria).

The name Scallop Hook-tip given to this species by Moses Harris in 1775, doubtless referred to the ragged outlines of the fore wings. These wings are pale brown in colour, freckled and clouded with darker tints, and crossed by two dark-brown lines; the central dot is black, but often minute; fringes [ 137 ] white, chequered with brown. Sometimes the freckling is heavy and the clouding very dark, becoming almost black on the outer margin; such specimens seem to be referable to var. scincula, Hübn. In another form the fore wings are ochreous brown, with very tiny freckling and only light clouds on the upper part of the outer margin. The hind wings in all the forms are pale whitish brown, with a black central dot, and brown marginal line; in the darker specimens these wings are clouded or suffused with dark brown (Plate 71).

The egg is pale yellowish when laid, but changes afterwards to reddish. The full-grown caterpillar is pale brownish, marked with darker or reddish brown on the back and sides, and raised spots; there are double-pointed humps on rings two and three, and a similar but smaller elevation on ring eleven. In the younger state the caterpillar is blackish, with whitish marks on the fourth, seventh, and eighth rings, and some white dots on the end rings. It feeds on the upper surface of the leaves of birch in June and July, and again in August and September.

Chrysalis, reddish brown, the ring divisions blackish grey; powdered with whitish, and appearing as though dusted with flour. Attached by the anal spike to the interior of the silken web-like cocoon. In the Figure (Plate 69) the pupa is shown hanging from the ruptured cocoon, upon the covering leaf of which a half-grown caterpillar is depicted.

The moth is out in May and June, and a second generation appears in August. It is not uncommon in most birch woods, and on heaths and commons, where birch flourishes; but the perfect insect, which rests on leaves and twigs of trees and bushes, and the herbage under them, is not so frequently or so easily obtained as the caterpillars. The latter may be searched for in the daytime, or they may be dislodged by beating.

Widely distributed throughout England, but local or scarce in Lancashire and Yorkshire and northwards; also, according to [ 138 ] Barrett, in Devonshire and in the fens of Norfolk and Cambridge. It occurs in the Clydesdale district, Ross, Argyllshire, and Sutherland in Scotland; and in Ireland it seems to be widely spread and common in some localities.

The Chinese Character (Cilix glaucata).

Probably in reference to the grey-brown oval blotch on the middle of the white fore wings, this moth was known to the older entomologists by the English name of "Goose-egg." On the blotch, however, there are silvery marks on the veins, and below it (often attached) there is a blackish blotch with some bluish silvery scales upon it. These markings probably suggested to Haworth the name Chinese Character by which it is commonly known (Plate 71).

The caterpillar is reddish brown, with a darker line along the back, and a paler patch on rings three to five, extending as a narrow stripe to the dark-brown spiked tail; two raised warts on rings two and three, with a white dot between the hinder pair. Head darker brown, paler in front. It feeds in June and early July, and in September and October, chiefly on hawthorn and sloe, but it will also eat apple and pear. The chrysalis, which is enclosed in a brown, rather tough, silken cocoon, spun up among leaves or under loose bark, is greyish on the wing covers, and reddish on the body.

The moth is out in May and early June, and again from late July well into August. Sometimes it may be seen resting on a leaf in a hedgerow. When disturbed in the daytime, which may happen where one is beating the bushes, it falls, rather than flies, to the ground. At night it may be netted as it flies along the hedgeside or wood borders in almost every county of England and Wales. In Scotland its range seems not to extend north of Clydesdale. Kane states that it is "widely spread, but not generally at all numerous" in Ireland.

Moths of the British Isles Plate070.jpg


Pl. 70.
1. Oak Hook-tip: caterpillar.
2, 2a, 2b, 2c. Barred Hook-tip: egg, enlarged; caterpillar, chrysalis and cocoon.

Moths of the British Isles Plate071.jpg


Pl. 71.
1. Oak Hook-tip, male; 2 female. 3. Barred Hook-tip, male; 4 female.
5, 7. Scalloped Hook-tip, males; 6, 8 females.
9. Chinese Character, male; 10 female.