The Moths of the British Isles Volume I Part 13

Pl. 49.

1, 1a, 1b, 1c. LACKEY: _eggs, caterpillar, chrysalis and coc.o.o.n_.

2, 2a. HYBRID BETWEEN LACKEY AND GROUND LACKEY: _eggs and caterpillar_.

3. GROUND LACKEY: _caterpillar_.

{111}

_Malacosoma_ hybr. _schaufussi_, Standf.--In 1884 Dr. Standfuss made some experiments in crossing three species of _Malacosoma_, and one of these was the pairing of _M. neustria_ [male] with _M. castrensis_ [female]; the offspring he christened as above. Since that time others have succeeded in crossing the two species with varying results.

On August 13, 1906, Mr. Percy Richards sent me a small batch of eggs (Plate 49, Fig. 2a) laid by a female, _M. castrensis_, that emerged in a breeding cage, and had paired with a captured male, _M. neustria_, he introduced.

The larvae hatched out one or two at a time, from April 7 over a period of more than a fortnight. Few of the caterpillars would commence to feed, and of those that took to the plum and sallow with which they were supplied, only four reached maturity. Three of these pupated during late June and early July, and three moths, all females, have emerged up to date, one on July 28, another on August 6, and a third on August 13. The second specimen was very much crippled, probably owing to the coc.o.o.n having been accidentally injured. One caterpillar was still feeding on August 14, but died about the 26th.

The mature larva (Plate 49, Fig. 2) has the head and markings thereon like _neustria_, also the black spots on the first thoracic segment, but they are rather large and inclined to unite. The bluish line along the sides is dotted and freckled with black rather more thickly than in _castrensis_; the dorsal line is very thin, but bluish as in _castrensis_, and the red lines on each side of it are broad.

In colour the three moths are deeper brown than any form of either parent species that I have seen, but the transverse lines, and especially the outer, are most like those of _neustria_.

It should be mentioned that much information on Hybridism in the Lackey moths and other species will be found in Tutt's "British Lepidoptera," vol.

ii. {112}

THE PALE OAK EGGAR (_Trichiura crataegi_).

In its typical form the male of this species (Plate 50, Figs. 1, 2) is ashy grey, with a darker central band on the fore wings; and the female is dusky greyish-brown, also with a darker band. The colour of the male varies in shade from almost whitish (var. _pallida_, Tutt), to blackish grey; in the paler forms the central band of the fore wings is often of a purplish tint, and in the darkest forms the band is almost black. The female var.

_pallida_, is pale buff.

The eggs, which are brownish, inclining to reddish on the micropylar area, are covered with dark grey hairs from the body of the female and laid side by side in a chain-like arrangement on a twig of hawthorn or sloe (those figured on Plate 51 were deposited in a box, and not securely attached).

From eight to twelve is said to be the usual number in a batch, and each female will deposit an average of 160 eggs.

The caterpillars do not hatch out all at the same time, but by ones and twos, at intervals spreading over a period of two, or perhaps three, weeks.

Several forms of the caterpillar have been described, but the ground colour is generally more or less black above and greyish on the sides; the ornamentation comprises interrupted white or whitish stripes, streaked or clouded with reddish, and reddish warts; the hairs are reddish brown. The example figured on Plate 51 was from eggs laid by a female moth in Selkirk, South Scotland. From the age of three weeks until it became full grown it was black marked with yellow on the back and orange on the sides; hairs pale greyish mixed with black ones, especially on the back towards the black, glossy, and somewhat hairy head. It hatched on April 26, was reared on plum, pupated early in June, and the moth, a darkish grey female, emerged on July 31. Another caterpillar that hatched on May 1, and two others from still later hatchings, were then in chrysalis.

[Ill.u.s.tration]

Pl. 50.

1. PALE OAK EGGAR, _male_; 2 _female_.

3. DECEMBER MOTH, _female_; 4 _male_.

5. SMALL EGGAR, _male_; 6 _female_.

[Ill.u.s.tration]

Pl. 51.

PALE OAK EGGAR.

_Eggs enlarged, and caterpillar._

{113} The caterpillar may be found from April to June on hawthorn and sloe, and it is said also on birch, oak, sallow, apple, bramble, etc. Those that I have found resting by day on shoots of hawthorn, apparently enjoying the sunshine, have almost invariably been "ichneumoned"; but others that came up after sunset to feed on the shoots were generally healthy. Usually the caterpillar feeds up and pupates the same year, but on the moors in Aberdeenshire and some other parts of Scotland it is said to hibernate and to complete its life cycle the following summer and autumn. Furthermore, the moths from these winter larvae are much darker than normal, and have been doubtfully referred to var. _ariae_, Hubn., a form found in the Alps, Scandinavia, and Finland.

The moth is out in August and September, and occurs in wooded districts throughout the southern half of England, but northwards from the Midlands it is uncommon; it is found in several parts of Scotland to Inverness. In Ireland it is reported (Birchall) to have occurred in Killarney, and Kane mentions that "a blackish form was taken at Magilligan, near Derry, by W.

Salvage. Its larvae were feeding on blackthorn." The range abroad extends through Europe to Armenia and Asia Minor.

THE DECEMBER MOTH (_Poecilocampa populi_).

This is a rather thinly scaled moth; the general coloration is sooty brown; the wings are suffused more or less with greyish; there are two pale ochreous cross lines on the fore wings, the first enclosing a reddish brown basal patch; hind wings rather paler with a diffuse whitish central band; fringes brown chequered with pale ochreous. Head brown, collar brownish, tipped with pale ochreous in the male. The female is rather larger than the male. The moth is figured on Plate 50, and the eggs and caterpillar on Plate 53.

The eggs, which are laid on the bark of trees, are whitish grey, variegated or mottled with darker grey. {114}

The caterpillar hatches out in April, and when nearly full grown is ochreous, but so thickly dotted and freckled with black as to appear of a dark brown coloration; the back is clothed with dark short hairs, and the sides with long paler hairs; on the back of the first ring is a reddish brown mark divided by a white line; a double row of whitish dots along the back, most distinct on rings two and three, where they are placed on a velvety black bar; on each side of the white dots is a reddish brown interrupted line. Head ochreous brown, thickly dotted with black and clothed with pale hairs. Underparts ochreous, spotted and lined with blackish. Feeds on the foliage of most trees, and is said to eat lettuce.

April to June.

Chrysalis glossy red brown, in a coc.o.o.n spun up among dead leaves, etc., under loose bark, or on the ground.

The moth does not emerge until October, and in that month, but more frequently in November and December, the males may be seen around gas lamps quite late at night.

Although found chiefly in woods it is not essentially a woodland species, as it occurs in districts where there are no woods but plenty of trees growing in parks, fields, or even hedgerows. It is fairly common generally throughout England and Wales, but becoming rather more local northwards to c.u.mberland. It occurs through Scotland to Sutherland, but is nowhere common. In Ireland it is widely distributed, and not uncommon near Dublin, and at Favour Royal, Tyrone. Abroad it ranges through Northern and Central Europe.

THE SMALL EGGAR (_Eriogaster lanestris_).

Also a brownish insect with somewhat thinly-scaled wings. The fore wings are light reddish brown with a whitish patch at the base, a white spot about the centre, and a whitish transverse line beyond; the hind wings are smoky brown and have a pale central band. The female, which is larger than the male, has a conspicuous greyish a.n.a.l tuft, the hairs from which she uses to cover over her pale oily green eggs when they are deposited in cl.u.s.ters on twigs of hawthorn or sloe in February or March. Plate 50, Figs.

5, 6; Plate 53, Figs. 2, 2a.

[Ill.u.s.tration]

Pl. 52.

OAK EGGAR MOTH.

[Ill.u.s.tration]

Pl. 53.

1, 1a. DECEMBER MOTH: _eggs and caterpillar_.

2, 2a. SMALL EGGAR: _eggs and caterpillar_.

{115} The caterpillar is black or greyish black, with reddish brown hairs, and a series of black-edged yellowish brown, or reddish brown blotches on each side of the back; these blotches are outlined in pale yellowish and occasionally connected by a line of the same colour. From the time they are hatched until nearly mature the caterpillars live in companies on a closely woven web of silk on a branch of hawthorn or sloe, only leaving their habitation to feed. These webs may often be seen on hedgerows from May to July. The brown chrysalis is enclosed in a solid-looking oval coc.o.o.n of a pale ochreous or whitish colour. Not all the moths emerge the following year: some will remain in the chrysalis over two or three winters, and occasionally they have been known to emerge seven years after pupation. The moth is said to be fully formed within the chrysalis all the time, but for some reason will not emerge, although if extracted from its sh.e.l.l, the moth has been known to expand its wings in the ordinary way. Barrett states that in the middle of February, after a moth had emerged, he "put a large number of coc.o.o.ns upon a warm mantelpiece and obtained scores of moths within a few hours."

Generally distributed over the southern half of England; plentiful in some years in the Southern and Eastern Counties. Northwards and in Scotland it is local and less frequent. Kane states that in Ireland it is very locally abundant. The range abroad is through Central and Northern Europe to Southern Lapland, and eastward to Siberia and Amurland.

THE OAK EGGAR (_Lasiocampa quercus_).

The three moths, one male and two females, shown on Plate 52, were reared from caterpillars obtained in Kent, and they {116} represent the more or less ordinary South English forms of the species. Sometimes the ground colour of the male is more distinctly reddish, or rust tinted, and the yellowish bands narrower on all the wings. Or the bands may be much broader than in the male figured, and the widening is effected by extension in the form of rays towards the outer margins of the wings. A form that has been referred to, in error, as var. _roboris_, Shrank (= _marginata_, Tutt), has the outer margins of all the wings broadly yellow. I have not seen an English example of this form, but I have a reddish specimen in which the yellow band on the fore wings is broader than usual, and the whole of the outer third of the hind wings yellow, with a slight brownish shade on the external margin; this is _semimarginata_, Tutt, and is also identical with var. _roboris_ of other British authors. The white spot usually present on the fore wings varies somewhat in size and shape; it is often seen on the under as well as the upper surface of the wings, except in the lighter coloured forms.

Var. _callunae_ (The Northern Eggar), is shown on Plate 54. The chief features of this form are the generally darker coloration in both s.e.xes, the yellow patch at the base of the fore wings of the male, and the outward turn of the lower ends of the yellow bands. All these characters are subject to modification; the yellow bands may be very narrow at one extreme, or greatly widened at the other, and the hind wings may occasionally be bandless; the basal patch is often of large size, but in some examples it is entirely absent. Sometimes the bands are greenish in colour (var. _olivaceo-fasciata_, c.o.c.kerell), and more rarely, perhaps, the greenish tinge extends over the whole of the wings (ab. _olivacea_, Tutt).

It should be noted here that the var. _olivaceo-fasciata_ has occurred once or twice in South England, but this phase of aberration seems to be more connected with _callunae_ than with _quercus_.

[Ill.u.s.tration]

Pl. 54.

NORTHERN EGGAR.

[Ill.u.s.tration]

Pl. 55.

OAK EGGAR.

_Egg, natural size and enlarged; caterpillars and coc.o.o.n._