The Moths of the British Isles Volume I Part 2

The species is widely distributed throughout the southern counties of England, and in some of them, more especially around London, it is common.

In the Midlands it seems to be {20} scarce, and apparently does not occur further north than Yorks.h.i.+re, from which county there is only a single record. It is common in Europe, except in the more northern and southern parts, and its range extends eastwards into Siberia.

THE POPLAR HAWK-MOTH (_Smerinthus_ (_Amorpha_) _populi_).

On Plate 5 are three slightly different examples of this moth. In colour it is most frequently ashy grey, with a brownish central band, and other markings; there is a white spot on the fore wings and a conspicuous red patch at the base of the hind wings. The female is generally paler than the male, and often has a pinkish tinge. Specimens of a pale buff colour are sometimes obtained, and these are most often of the female s.e.x, although male examples of this form are not unknown. Among unusual aberrations is one described as having the wings, legs, thorax, and abdomen of a colour between brick-red and chocolate, suffused with a whitish bloom as on ripe plums. Another had the hind wings unadorned with red. Specimens from Aberdeens.h.i.+re and Sutherlands.h.i.+re are smaller than English examples, and the males are almost always more brightly and distinctly marked.

A very large number of Gynandrous, or "hermaphrodite" specimens have been recorded, several of them from Britain; in most of these the gynandromorphism is bilateral, that is the insect is wholly male on one side, and entirely female on the other. In some the right side is male, in others the left side; the opposite side in each case being female. Much information on this subject and on Hybridism of the Sphingidae will be found in Tutt's "British Lepidoptera," vol. iii.

The pale s.h.i.+ning green eggs are laid, generally singly, but sometimes in twos, threes, or more, on either surface of a leaf of poplar or sallow. Now and then batches of eggs may be found, and these have probably been laid by females that were crippled on emergence, or had been afterwards injured in some way and so were unable to fly.

[Ill.u.s.tration]

Pl. 4.

POPLAR HAWK-MOTH.

_Eggs, natural size and enlarged; caterpillar and chrysalis._

[Ill.u.s.tration]

Pl. 5.

POPLAR HAWK-MOTH.

{21}

[Ill.u.s.tration: FIG. 17.

EGGS OF POPLAR HAWK-MOTH.]

When full grown the caterpillar is green, roughened with yellow points, oblique stripes on the sides yellow, spiracles reddish, horn of the general colour, sometimes tipped with reddish. Head triangular in shape, but not pointed on the top. A reddish spotted form of the caterpillar is not very uncommon. In its very early life the head is rather triangular than rounded, as is the head of the young caterpillar of the previous species, and also that of the Eyed Hawk. Feeds on poplar, aspen, sallow, and willow, and may be found from July to September and sometimes October. Chrysalis blackish, rougher than that of the Lime Hawk. It lies in the ground so close to the surface that it is often exposed when the garden borders under or near poplars are raked over. The moth appears in May and June as a rule, but in backward seasons it may not emerge until July or even August.

Caterpillars from eggs laid in early May are likely to feed up and attain the perfect state in late July, and eggs resulting from these will pa.s.s through the caterpillar state to that of chrysalis by about {22} September.

Three broods have been obtained in one year, but this is exceptional and under a forcing method of treatment. The early stages are figured on Plate 4. This is certainly the commonest of our Hawk-moths, and it seems to occur throughout our islands, except that in Scotland it is not recorded further north than Sutherland and Ross. Wherever there are poplars, sallows, or willows, there too most probably will be this caterpillar in its season; the moth also will be almost certainly seen by any one who may care to keep an eye on the stems of poplars or adjacent fences at the right time.

Sometimes the insect will introduce itself to the household, after lighting-up time, much to the alarm of those who, not aware of the harmless character of their visitor, look upon it with considerable suspicion.

Distribution abroad--Europe (except the polar regions and Greece), Armenia and the Altai.

THE EYED HAWK-MOTH (_Smerinthus ocellatus_).

Except that there is sometimes an absence of rosy tinge on the fore wings, and that the brownish markings may be lighter or darker, this species does not depart very greatly from the typical form shown on Plate 7.

Cross pairings between the Eyed-hawk and the Poplar-hawk are not altogether difficult to obtain, but the female _populi_ pairs more readily with male _ocellatus_ than the female of the last named species will with the male of _populi_. Very few such cross pairings have been noted in a wild state, but several cases of the kind are known to have occurred in captivity. The results are hybrid moths, and these have some of the characters of each parent, and have received distinctive names. Thus the offspring of _ocellatus_ [male] _populi_ [female] are the _hybridus_, Steph., whilst that of _populi_ [male] _ocellatus_ [female] are referable to _inversa_, Tutt.

[Ill.u.s.tration]

Pl. 6.

EYED HAWK-MOTH.

_Eggs, natural size and enlarged; caterpillars and chrysalis._

[Ill.u.s.tration]

Pl. 7.

EYED HAWK-MOTH.

{23}

The eggs, which are generally laid singly or in pairs on either side of a leaf, sometimes on a stalk, are yellowish-green in colour. The sh.e.l.l is said to be netted, but under a fairly strong lens this does not show. About four hundred is probably the average number for a female to lay in a state of nature, but they seem not to deposit so many when reared from the egg in confinement. As the moth, except under stress of circ.u.mstances, places her eggs on the foliage of trees and bushes in selected positions, the business of egg laying takes about six nights to perform. Even when she is unable to fly she will crawl from twig to twig and glue an egg here and there on the leaves, but rarely more than two on a leaf. On a small sallow bush in my garden, I once counted eighty-four eggs on the lower leaves and the main stem. Green, inclining to yellowish or greyish, is the colour of the full-grown caterpillar. It is roughened with white points, and has seven whitish oblique stripes on the sides. These stripes are edged in front with darkish green and occasionally tinged with violet. The horn is bluish, merging into green towards the dark tip, and roughened with white points.

Head triangular in shape, the top pointed; face tinged with bluish.

Sometimes bright red spots appear on the sides in some examples of the caterpillar. In the quite young stage the head is usually rounded; the horn, which appears reddish, is about one third the length of the caterpillar.

Sallow, willow, and apple are the more general food plants, but poplar and privet have been reported. I have sometimes found the larva on _Salix repens_, and also on crab-apple (_Pyrus malus_). It may be found in July and August. In some years, when the moths emerge in May, caterpillars are found as early as June, and this is followed by the occurrence of the caterpillar again, as a second brood, in August and September. When quite mature the caterpillar enters an inch or two into the soil, and there forms a weak sort of cell in which it shortly afterwards turns to a brown, or blackish-brown, smooth and {24} rather glossy chrysalis. The early stages are figured on Plate 6.

The moth usually emerges in June, earlier or later, according to season.

Under very favourable circ.u.mstances some of the moths will leave the chrysalis in May and give rise to a second generation in July. An unfavourable year, on the other hand, r.e.t.a.r.ds emergence, and the moths do not come up until late June or mid-July; such has been the case this year (1907).

Generally distributed and by no means uncommon throughout the southern half of England, but somewhat local northwards. It has been recorded from the most southern counties of Scotland, and Kane states that in Ireland it is widely distributed but usually scarce.

The method of folding down its wings in repose is very similar to that of the previous two species.

THE DEATH'S-HEAD HAWK MOTH (_Acherontia (Manduca) atropos_).

The fine moth represented on Plate 8 is the largest species found in the British Isles, although in measurement from tip to tip when the wings are expanded it does not exceed that of the next species, both varying in this respect from 4 to 5 inches. It is, however, a stouter bodied insect, and its wings are broader. The colour and markings are so well shown in the ill.u.s.tration that a description is unnecessary. Beyond a greater or lesser intensity of the paler markings on the fore wings and the thorax, also some modifications in the black band of the hind wings, there is nothing very striking in the way of variation. Perhaps the most important aberrations are connected with the inner black band of the hind wings, which may be much widened and diffuse, or, on the other hand, entirely absent.

When full grown, the caterpillar attains a length of nearly 5 inches, and is of considerable thickness throughout. Usually {25} the general colour is some shade of green, varying to yellowish, but in some examples it is brown, more or less tinged with violet; others again are of a blackish hue.

The seven oblique side stripes are purplish or violet brown, edged with yellowish; they are absent from the three rings nearest the head; the rough, double curved horn is of the body colour. The greenish forms are sprinkled with violet dots, and the brownish forms with white ones. Most frequently found on the leaves of potato; it feeds also on the "tea-tree"

(_Lycium barbarum_), woody nightshade (_Solanum dulcamara_), and s...o...b..rry (_Symphoricarpus_). Fig. 1, Plate 9, represents the brown form of the caterpillar.

When ready to enter the chrysalis state, the caterpillar burrows from 2 to 4 inches below the surface of the soil, and there forms a large chamber, the walls of which are not very substantial and are easily broken. After resting therein for a week, or two, it turns to a dark brownish, rather glossy, chrysalis. (Plate 11, Fig. 1). The earthen coc.o.o.n, frail as it is, seems to be a protection to the chrysalis, guarding it from too much moisture on the one hand, or dryness on the other. I always found that when chrysalids from caterpillars that I have obtained were left undisturbed the moths emerged well enough; but when they were turned up out of the ground by the potato diggers, and, of course, without covering, they were almost certain to perish if the attempt were made to keep them through the winter.

In the latter case, the only chance was to endeavour to induce the moth to emerge as soon as possible by bringing them under the combined influence of warmth and moisture.

This species was known to Mouffett, who figured it in 1634, but it does not appear to have received an English name until 1773, when Wilkes figured it as the "Jasmine Hawk Moth." Moses Harris, in 1775, called it the "Bee Tyger Hawk Moth," but three years later he changed the name to the Death's Head, the name by which it is still known, although in some {26} parts of England, as well as in Ireland, it is referred to as the "bee robber." In connection with the latter name, it may be mentioned that the moth's "tongue," or proboscis, is short, and not adapted for obtaining sweets, of which it is very fond, from long-tubed flowers, consequently it filches honey from the bees, and, with this object, has been known to enter bee-hives, at least those of the old straw-skep pattern. The moth is also said to have a liking for the sap exuded by wounded trees. Although the species may, perhaps, be with us in certain favoured localities every year, it does not often occur, in any stage, in numbers sufficient to attract general attention. I have not searched the chronicles of _Atropos_ in Britain earlier than 1864, but from these it seems that the species was widely distributed and generally common in 1865, 1868, 1878, 1885, 1896, and 1900. More or less common in certain localities in 1867, 1869, 1870-1872, 1877, 1880, 1882, 1884, 1893, 1895, 1899, 1911, and 1917. In the other years it was scarce, or apparently absent.

The moth is always very much less in evidence than the caterpillar, or even the chrysalis. Sometimes the former is seen in May or June, or even earlier, and it has been supposed that these precocious specimens have hibernated after emergence from the chrysalis here during the previous autumn. The question of hibernation need not be entertained, but there may be doubt as to whether the specimens are British born or aliens. I am inclined to the latter view. The moths are often noted at sea long distances from land. A specimen was captured on board a vessel in the North Sea on April 28, 1903, and it was still alive, although it had been roughly dealt with, on May 8 of that year. In 1899 a moth was taken at Chester, about the middle of May, and one on June 20 at Chichester. Probably, although undetected, other specimens were also about the country, and maybe at even earlier dates than those recorded. However, during the year larvae and pupae were found, at the end of July, at Chilton, Suffolk, and at Bridgwater, Somerset, and in early August in Somerset, and at Dover. A moth was captured in August at Marlow, Bucks., one was taken at Christchurch on September 19, one at Reigate, September 25. Several specimens occurred in Devon and Cornwall in the autumn, and at Deal early in October. Larvae were found, too, from the second week in September to the end of that month in several parts of the country. Moths seem to have been reared in early September from the early August caterpillars; whilst the September caterpillars attained the perfect state towards the end of the month and in October. Two pupae, found at Penarth on September 12, produced moths in from four to six days afterwards; four other chrysalids, obtained in Hants about mid September, yielded moths between September 21 and the beginning of October.

[Ill.u.s.tration]

Pl. 8.

DEATH'S-HEAD HAWK MOTH.

[Ill.u.s.tration]

Pl. 9.

1. DEATH'S-HEAD HAWK-MOTH.

_Eggs, natural size and enlarged; and caterpillar._ 2. CONVOLVULUS HAWK-MOTH CATERPILLAR (DARK FORM).

{27} From the foregoing there can be no question that there are at least two generations of the moth in some years, and in our own country, but we have even clearer evidence of this in the records of 1900, when a moth was taken in the spring at Ayton, Berwicks.h.i.+re, another at Worsborough Bridge on June 18, and a third at Kilmarnock, on a bee-hive, July 11. Caterpillars were found during late July and August in South Scotland and various parts of England, and moths were reared from some of these. In September and October caterpillars were found more commonly, and two or three moths were captured, in various places, between August 19 and October 9; others, reared from September caterpillars, emerged from October 30 to November 24.

By the rustic, and possibly the uninitiated generally, the moth is looked upon as something uncanny. This is probably due to the fact that the creature, when handled, emits a peculiar sound that has been described as a shrill squeak. According to Kirby, the statement made by Rossi that the sound is produced by air from the air-sacs being forced through the {28} proboscis, has been verified. Another dread-inspiring character of the insect is the marking on the thorax, which has been likened to a skull and crossbones. The squeak is said to have the effect of quieting the bees, they being under the impression that it proceeds from their queen.

It has been taken at some time or another in almost every part of the British Isles, right up to and including the Shetlands. Except that it has not been observed in the more northern parts, the species is found throughout Europe, North and South Africa, the Canary Islands, and the Azores. It is also represented in Southern India, extending to the Malays, and in China, Corea, and j.a.pan.