6. Fore-wings diffused with dark greyish-black, except two broad bands
of the original light colour extending from costa to dorsum; hind-wings
darker than usual (fig. 45).
7. Fore-wings with a dark brown central band; hind-wings clouded with
dark brown towards termen, with a faint curved transverse line near the
middle (figs. 39 and 40).
All these varieties occasionally have tufts of orange-yellow scales on
both the wings and on the body, and they also vary in other minor
particulars (fig. 46).
The egg of this insect when first laid is oval in shape and light green
in colour, becoming bronzy a few days before the emergence of the larva.
The young larva is very attenuated, with only ten legs. {97}Its colour is
pale yellow striped with brownish-pink near the segmental divisions. It
is very active, and does not devour the egg-shell after emergence.
The full-grown larva has the body much flattened underneath. In colour it
is pale brownish-pink, with numerous irregular darker markings, which in
some specimens almost form two broad subdorsal lines. The under surface
of the larva is pale green. There is a series of fleshy filaments of a
pinkish-brown colour along each side of the insect, and an extra pair of
prolegs on the ninth segment.
This caterpillar is, however, very variable, its colouring appearing to
depend largely on its surroundings. The favourite food-plants are
_Leptospermum ericoides_ and _Aristotelia racemosa_. The larvæ found on the
former plant are usually pale yellowish-brown, whilst those from the latter
are much darker brown, often mottled with grey like the stems of the
_Aristotelia_. A specimen I once found on a mountain beech (_Fagus
cliffortioides_), the gnarled stem and branches of which were covered with
grey lichens and mosses, was mottled with the most beautiful shades of
greenish-grey. These larval varieties are very interesting, and in order to
test the direct influence of food on the colouring of the larvæ, I once
divided a batch of eggs deposited by a single female into two equal parts,
and fed one half on _Aristotelia_, and the other half on _Leptospermum_.
The differences in colouring between the two lots of larvæ thus treated
were, however, of the most trivial description. This somewhat surprised me
at first, as I had previously observed quite distinct varieties on each
plant, when found in a state of nature. Hence I am now disposed to think
that these differences have been brought about gradually, by natural
selection acting on larvæ feeding on the same plant for a large number of
generations. By this means a sufficient amount of variation might be
accumulated, to cause the closest possible approximation in colouring to
the stems of the several food-plants. It is also noteworthy that many of
these food-plants grow in widely dissimilar localities, so that the free
inter-breeding of insects dependent on them would not be likely to occur,
and thus the peculiarities of colouring adapted to the stems of each
food-plant would not be disturbed by the effects of inter-breeding.
In connection with the foregoing experiment it is also interesting to
observe, that the specimens fed on _Aristotelia_ matured much more rapidly
than those on _Leptospermum_; the former plant evidently being the more
nourishing food for the larvæ. Also that out of the batch fed on
_Aristotelia_ 28 became moths, of which 12 were males and 16 females;
whilst out of those fed on _Leptospermum_ only 24 became moths, of which 15
were males and 9 females. In all other respects, excepting food-plant, the
two lots of larvæ were subjected to identical treatment.
During the day this larva rests quietly attached to the stem of its
food-plant, where it is very difficult to detect, as the filaments so
closely embrace the twig or tree-trunk that the whole insect exactly
resembles a swelling in the stem.
The pupa of _D. floccosa_ is enclosed in a loose cocoon on the surface of
the ground.
The perfect insect appears about September, and continues in more or less
abundance until the end of April. There are most likely several broods in a
season, and, as we frequently meet with specimens of the moth on mild days
in the middle of winter, it probably also hibernates.
This insect is usually observed at rest on fences and tree-trunks, where
its grey mottled colouring causes it to closely resemble a patch of lichen.
{98}DECLANA JUNCTILINEA, Feld.
(Plate X., fig. 37 [M], 38 [F].)
This species has occurred occasionally in the Wellington Botanical Gardens.
It is no doubt found elsewhere, but I cannot give any other localities with
certainty.
The expansion of the wings of the male is 1¼ inches, of the female 1-3/8
inches. The fore-wings of the male are pale yellowish-brown, with two
indistinct, irregular, transverse darker lines near the base, a
conspicuous curved line a little beyond the middle, followed by a
blackish patch; _there is a series of very fine parallel oblique brown
stripes on the costa_, and several series of curved, blackish marks near
the termen, and on the central portions of the wing. The fore-wings of
the female are much greyer, with a conspicuous, irregular, white streak
from the apex towards the dorsum, the central portions of the wing are
white, and, with the exception of the fine, oblique costal stripes, the
other markings of the male are usually absent. The hind-wings of both
sexes are dull ochreous. The strongly pectinated antennæ of the male, and
the oblique costal markings of both sexes, will at once distinguish this
species from any of the varieties of _Declana floccosa_.
This moth varies in the intensity of the markings, which in some specimens
are very indistinct.
The perfect insect appears from November till March. It is generally
captured on blossoms in the evening.
DECLANA HERMIONE, n. sp.
(Plate X., fig. 36.)
A single specimen of this very handsome insect was captured at Khandallah
near Wellington.
The expansion of the wings is 1¼ inches. _The fore-wings are bright
purplish-brown, clouded with silvery-white towards the middle and on the
termen_; there is a very fine oblique chocolate-brown mark at the base, a
broad broken transverse band at about one-eighth; a fine curved
transverse line at about three-fourths, shaded towards the termen; there
are four wavy brown marks on the termen inclining obliquely upwards
towards the costa; the termen itself is narrowly edged with
chocolate-brown. The cilia are silvery mixed with brown; the termen is
very strongly bowed. The hind-wings are grey, shaded with purplish-grey
towards the termen; the cilia are grey.
The type specimen was captured at sugar in November.
DECLANA GRISEATA, n. sp.
(Plate X., fig. 32 [F].)
This species has occurred at Wellington in the North Island, and at Lake
Wakatipu in the South Island.
The expansion of the wings of the male is 1-1/8 inches, of the female
1-3/8 inches. _The fore-wings are dull slaty-grey, with a slightly paler
central band_; there is a fine oblique wavy transverse line at about
one-fourth, another at about one-half, and indications of a third at
about three-fourths; _numerous minute black streaks are thickly scattered
over the wing, especially near the base and the termen_; the outline of
the termen is very slightly scalloped. The hind-wings are pale grey,
darker near the termen. The body is very dark slaty-grey. _The antennæ of
the male are not bi-pectinated._
The perfect insect appears in January, and is attracted by light. It is a
scarce species.
DECLANA NIVEATA, Butl.
(_Declana niveata_, Butl., Cist. Ent. ii. 500. _Atossa niveata_, Meyr.,
Trans. N. Z. Inst. xvi. 104.)
This species has occurred at Dunedin, in the South Island.
"The expansion of the wings of the male is 30 mm. (about 1¼ inches).
Fore-wings elongate-triangular, costa somewhat sinuate, termen rounded,
dentate; dull white, faintly irrorated with grey; costa marked with short
indistinct dark grey direct strigulæ; an irregular line towards base, and
another twice angulated about two-thirds, obscurely indicated by dark
grey scales; some scattered {99}dark grey strigulæ before termen.
Hind-wings moderate, termen crenate, angularly projecting in middle;
wholly white.
"I took one fine specimen at rest on a tree-trunk near Dunedin, in
February."--(Meyrick.)
Family 6.--SPHINGIDÆ.
"Head with dense appressed hairs. Ocelli absent. Eyes glabrous. Antennæ
thickened towards middle or posteriorly, in male ciliated with partial
whorls. Labial palpi moderate, ascending, with dense projecting scales.
Thorax densely hairy beneath. Femora densely hairy. Fore-wings with vein
1_b_ furcate, 6 out of 8, 9 absent (rarely present in exceptional
individuals). Hind-wings with veins 3 and 4 approximated at base, 5 from
middle of transverse vein, parallel to 4, 6 and 7 connate or stalked, 8
connected by oblique bar with margin of cell before middle, more or less
approximated to 7 near beyond cell." (Plate I., figs. 12 and 13,
neuration of _Deilephila_ [after Meyrick].)
"This family is generally distributed, but is most plentiful in the
tropics. The imagos are usually large insects, with stout, heavy bodies,
elongate-triangular fore-wings with very oblique termen, and relatively
small hind-wings; the wing muscles are very strong, and the flight
exceptionally powerful. Ovum spheroidal, smooth. Larva stout, usually with
an oblique, projecting anal horn, anterior segments sometimes retractile or
raised in repose. Pupa subterranean."--(Meyrick.)
Only one genus is represented in New Zealand, viz., _Sphinx_.
Genus 1.--SPHINX.
"Tongue strongly developed. Antennæ less than one-half, gradually
thickened to apex, then pointed, apex slender, hooked. Thorax with low
double posterior tuft. Abdomen smooth, broad, conical, pointed. Tibiæ
with appressed scales.
"A moderately large genus, ranging over the whole world, but principally
characteristic of America. Imago flying at dusk, feeding on the
wing."--(Meyrick.)
This genus is represented in New Zealand by one almost cosmopolitan
species.