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 pass
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.
[Illustration]
Pl. 6.
EYED HAWK-MOTH.
_Eggs, natural size and enlarged; caterpillars and chrysalis._
[Illustration]
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 shell 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 circumstances, 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 circumstances 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, retards 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 4½ 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
illustration 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 snowberry
(_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 cocoon, 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 larvæ
and pupæ 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. Larvæ 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 pupæ, 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.
[Illustration]
Pl. 8.
DEATH'S-HEAD HAWK MOTH.
[Illustration]
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, Berwickshire, 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 Japan.
CONVOLVULUS HAWK-MOTH, _Herse_ (_Sphinx_) _convolvuli_.
The older writers on British moths called this the "Unicorn" or "Bindweed
Hawk." The fore wings are whitish grey, mottled with darker tints, and, in
the male, clouded with blackish about the middle of the wing; the central
third is limited inwardly by a double blackish, wavy line, and outwardly by
an irregular, toothed, whitish line; running from one to the other are two
black streaks between the veins, and a similar streak nearer the costa is
waved upwards to the tip of the wing. The hind wings are whitish grey, with
a black stripe near the base, and two blackish bands between the stripe and
the outer margin. The thorax agrees in colour with the fore wings; the
tapered body has a broad grey stripe, enclosing a central black line along
the back, broad red and black and narrow white bands on each side (Plate
10).
The egg has been described as bright green in colour, and smaller than that
of the Privet Hawk. A female moth captured at Brighton on July 18, 1898,
deposited twenty-five eggs on _Convolvulus arvensis_ up to July 20, and the
next day a further eight were counted. The moth died on the 22nd.
Caterpillars hatched out July 27-28. These were whitish green, with a rough
blackish horn; after second moult they became green, with a darker green
stripe along the back, but without oblique side stripes.
[Illustration]
Pl. 10.
CONVOLVULUS HAWK-MOTH.
[Illustration]
Pl. 11.
1. CHRYSALIS OF DEATH'S-HEAD HAWK-MOTH.
2. " " CONVOLVULUS " "
3, 3a. CATERPILLAR AND CHRYSALIS OF PINE HAWK.
{29} In its more usual form the caterpillar, when full grown, is bright
apple-green, narrowly streaked with black; oblique stripes on the sides
yellowish; horn reddish, tip black. Head green, with black stripes. In some
examples the side stripes are edged above with bluish black; in others
there are blackish, more or less square, spots on the back, and patches on
the sides. Sometimes the general colour is blackish brown, with ochreous
bands and streaks. (This form is figured on Plate 9). When it occurs in
these islands it is generally found on the small bindweed (_Convolvulus
arvensis_), but it will eat _C. sepium_ and _C. soldanella_, and also the
cultivated kinds.
Referring to the caterpillar in Britain, Moses Harris, in 1775, wrote, "I
never heard of but two that were ever found--one by Mr. South [or Smith] of
Hampshire, which, he said, was green, and appeared in other respects so
like the privet that he was deceived. He fed it on the leaves of the lesser
bindweed. It changed into the chrysalis in the earth, in July, and the moth
was produced in September" (Dale).
The caterpillar figured by Harris is of the brown form, so we see that even
at this early date something was known of the life history of this moth and
the variation of the caterpillar. Since that date and up to 1894 only very
few larvæ appear to have been found in our islands. Barrett states that it
is doubtful if more than twenty had then been recorded. In 1895
caterpillars were obtained in Cornwall (four) and in Kent (two). Then for
five years little or nothing was reported about this stage, although the
moth seems to have occurred in varying numbers each year. In 1901, August
and September, over one hundred were reported, rather more than half of
which were taken from a hedgerow, overgrown with _C. sepium_, in {30}
Northumberland; twenty-six were obtained on the bindweed growing on
Lancashire sandhills, thirteen or fourteen in Essex, and others in
Bedfordshire, Kent, Hants, Dorset, and Devon.
Mr. Bell-Marley obtained thirty eggs, September, 1897, and although these
were kept in a cold room, thirteen caterpillars hatched, September 21. They
were supplied with _Convolvulus arvensis_ and _C. soldanella_, and seemed
to relish one as much as the other. Seven died during the first three
moults. The bindweeds being nearly over, seedlings were raised by forcing,
but before these were ready the larvæ had been on short commons, and just
immediately before the seedlings came to hand, had been twenty-four hours
without food. On these tender seedlings and some endive the remaining
larvæ, six in number, attained full growth in December. Two subsequently
died in the first half of that month, and the others went under the soil.
Only one, however, managed to assume the chrysalis state.
A small caterpillar, about one week old, described by Paymaster-in-Chief G.
F. Mathew ("Notes on Lepidoptera from the Mediterranean," _Entom._, xxxi.
115), was 1¾ inch long, pale glaucous green in colour, and thickly covered
with raised white dots; oblique side stripes white, bordered above with
dark green. On September 26, 1897, this caterpillar, which had been found
on September 18, was nearly full grown, and the writer goes on to state
that when gathering bindweed he obtained either eggs or tiny caterpillars
at the same time, and he eventually found that he had eight of them
altogether. They fed up rapidly, as a caterpillar, hatched about September
27, had gone down on October 18. Owing to accident, four produced deformed
chrysalids, but each chrysalis resulting from the others was perfect and
healthy on February 15, 1898. The large reddish-brown chrysalis is figured
on Plate 11, and it will be noted that the "tongue" case forms a curious
bent projection not unlike the handle of a pitcher. To give some idea of
the irregular way in which this migratory species visits our islands, it
will suffice to note the records only since 1894. Previous to that year it
was common, more or less generally, in 1846, 1868, 1875, 1885, and 1887.
[Illustration]
Pl. 12.
1. PRIVET HAWK-MOTH.
2. PINE HAWK-MOTH.
[Illustration]
Pl. 13.
PRIVET HAWK-MOTH.
_Eggs, natural size and enlarged; caterpillars and chrysalis._
{31} In 1895 an invasion seems to have effected a landing in the autumn, on
the south-west coast, chiefly, perhaps, in the Portland district, where
some fifty individuals were captured between August 12 and October 7;
twenty-three were caught near Bournemouth in August and September; sixteen
were taken at Christchurch, August 11 to October 2; and eight were recorded
from Milford. Several were reported from Devon, but only two from Cornwall,
although four larvæ were found in October at Port Wrinkle in the latter
county. At Cork, in Ireland, ten specimens were obtained in October.
Eastward, the captures in September were Norfolk (seven), Essex (one),
Lincoln (one). Odd specimens were taken here and there in Kent, Surrey, and
Herts. Several were reported from Gloucestershire, and one from South
Wales. The northward extension was evidenced by the capture of one example
at Alnwick, in Northumberland, in September, and of two in Aberdeenshire,
one as early as August 31, the other September 9.
The moth was almost a defaulter in 1896, but in 1897 about forty specimens
were taken, twenty-seven of which occurred in the Scilly Isles and eleven
at Portland (August 14 to September 16). One example was reported from
Yorkshire and another from Sutherlandshire, both in September.
A female was taken at Brighton, July 18, 1898, and in the autumn of that
year a good many specimens were obtained in various parts of England but
chiefly in the south. Portland again heading the list with over fifty
(August 4 to October 3) and a number were taken in the Isle of Wight during
September. Captures in 1899 seem to have been only pretty good. Portland
twenty, August 25 to September 20, perhaps less than a dozen in other parts
of England and one in Scotland, all in September {32} or October. In 1900
one specimen was taken at an Eastbourne electric light, and one at
Portpatrick in Scotland, both end of August. There appears to have been an
arrival of moths in this country in early June, 1901. Captures were
reported from Portland (June 2), Bedford, and S. W. London. Larvæ and pupæ
were found in many parts of England, as already mentioned. Then in August,
from about the 14th to September, moths were captured throughout the
greater part of England; in some places caterpillars were also obtained in
August, chrysalids in September. After a lull towards the end of the latter
month, moths suddenly appeared again during the first week in October.
Several observers remarked that whereas the August to September moths were
mostly females, large in size, and not in the best condition, the later
moths were chiefly of the male sex, small in size, and fine in condition.
It would seem therefore that these late specimens were the descendants of
the early August moths and represented a second generation on British soil
and the grandchildren of the June immigrants. Or, possibly, the
August-September moths were fresh immigrants, and the October specimens
their offspring.
The species was observed in several English counties during August and
September, 1911; and again in 1915. In 1917 it seems to have been more
widely spread over our islands, as specimens were reported from Ireland and
even Shetland.
Plants with tubular flowers, such as those of petunias, and the
sweet-scented white tobacco (_Nicotiana affinis_) are its especial
favourites, but it also visits the blossoms of pentstemon, geranium
(chiefly the scarlet variety), etc. It does not settle on the flowers but
inserts its long "tongue" into the tubes as it hovers on the wing in front
of them. Just at twilight it commences operations, but it may be seen
pursuing its investigations well on into the night (see Fig. 1, p. 2).