Volume I Part 16 (1/2)

There is some variation in the ornamentation; occasionally the white markings are of large size, or, on the other hand, may be almost or quite obscured. Very rarely the eye-spots are absent from all the wings (ab.

_obsoleta_, Tutt), and sometimes they are of abnormal shape. Now and then specimens of the female s.e.x are dark in colour, with red bands, and Barrett mentions an example of this s.e.x smoky black in colour, with still blacker markings (Plate 66).

The olive brown, clouded greyish eggs are laid in neatly arranged batches around the stems or twigs of plants; I once found a batch in North Devon on a loose piece of rock. The caterpillar when full grown is bright green, with black markings; the warts from which blackish bristles arise are yellow, sometimes pink or blackish. In an early stage it is black, with an orange line low down along the sides; later on it is still black, but ringed with orange. It feeds in June, July, and August on many kinds of plants, among which may be mentioned heather, bramble, sallow, sloe; also meadow-sweet (_Spiraea ulmaria_) and purple loose-strife (_Lythrum salicaria_).

The curious coc.o.o.n formed by the caterpillar (Plate 67) is {132} so constructed at the narrow end that the moth on emergence can easily pa.s.s through; after the insect's escape, the converging fibres forming the ”door” spring to again, and the point of exit looks pretty much as before the moth had pushed through. This kind of opening can only be worked from the inside, therefore enemies from without are unable to effect an entrance.

The moths are out in April and May, and the males may be seen on sunny days flying at a great pace over heaths, moorlands, and mosses, also about the borders of woods. The female flies at night, but it may occasionally be met with resting on heather or other herbage in the daytime. A freshly emerged female moth will, as a rule, attract as many specimens of the opposite s.e.x as one would care to take; all that one has to do is to take her in a box to some likely spot, and there await the coming of the males.

The species seems to be generally distributed throughout the British Isles, but is commoner in some parts than in others, and apparently rare in portions of the Midlands.

The distribution abroad extends through Europe to North Asia Minor and Armenia, and to Siberia, Amurland, and Ussuri.

DREPANIDae.

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 a.n.a.l {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 coc.o.o.n, spun up between leaves, or in a folded leaf, of the food plant.

Of the eleven species occurring in the Palaearctic 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.

[Ill.u.s.tration]

Pl. 68.

1. SCARCE HOOK-TIP, _male_; 2 _female_.

3, 5, 6. PEBBLE HOOK-TIP, _males_; 4, 7 _females_.

[Ill.u.s.tration]

Pl. 69.

1, 1a, 1b. SCALLOPED HOOK-TIP: _eggs, caterpillar and chrysalis_.

2, 2a, 2b. PEBBLE HOOK-TIP: _caterpillar, chrysalis and coc.o.o.n_.

3. SCARCE HOOK-TIP: _caterpillar_.