Volume I Part 2 (1/2)
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.