Transcriber's Note.
References in the book to its illustrations are by "Plate" with Roman
numerals. The illustrations themselves are labelled "Plate" with Arabic
numerals. A plate's number in Roman numerals is equal to a plate's
number in Arabic numerals. In several instances the author has spelled
words differently to the accepted way. That spelling is retained in
this transcription. The illustration on the book's cover is referred to
in the text as Plate 16.
PEEPS AT NATURE
EDITED BY
THE REV. CHARLES A. HALL
V. BRITISH BUTTERFLIES
IN THE SAME SERIES
EACH CONTAINING 16 FULL-PAGE ILLUSTRATIONS
(EIGHT OF WHICH ARE IN COLOUR)
LARGE CROWN 8VO. PICTURE COVER
BIRD LIFE OF THE SEASONS
COMMON BRITISH BEETLES
BRITISH MOTHS
WILD FLOWERS AND THEIR WONDERFUL WAYS
BRITISH LAND MAMMALS
BRITISH FERNS, CLUB-MOSSES, &c.
NATURAL HISTORY OF THE GARDEN
ROMANCE OF THE ROCKS
THE NATURALIST AT THE SEA-SHORE
POND LIFE
REPTILES AND AMPHIBIANS
PUBLISHED BY
A. AND C. BLACK, LTD., 4, 5 AND 6, SOHO SQUARE, LONDON, W. 1
AGENTS
AMERICA THE MACMILLAN COMPANY
64 & 66 FIFTH AVENUE, NEW YORK
AUSTRALASIA OXFORD UNIVERSITY PRESS
205 FLINDERS LANE, MELBOURNE
CANADA THE MACMILLAN COMPANY OF CANADA, LTD.
ST. MARTIN'S HOUSE, 70 BOND STREET, TORONTO
INDIA MACMILLAN & COMPANY, LTD.
MACMILLAN BUILDING, BOMBAY
309 BOW BAZAAR STREET, CALCUTTA
[Illustration:
PLATE 1.
1. Swallow Tail
2. Black-veined White
3. Large Garden White (Female)
4. Small Garden White (Male)
5. Green-veined White (Female)
6. Bath White (Male)
7. Orange Tip
8. Wood White (Male)
9. Pale Clouded Yellow]
BRITISH
BUTTERFLIES
BY
A. M. STEWART
CONTAINING 16 ILLUSTRATIONS, FIGURING
ALL THE SPECIES, VIZ.:
8 FULL-PAGE IN COLOUR
8 PAGES FROM PHOTOGRAPHS
A. & C. BLACK, LTD.
4, 5 & 6 SOHO SQUARE, LONDON, W. 1
1918
_First published May, 1912_
INTRODUCTORY EDITORIAL NOTE
I take it that this little "Peep at Nature," needs no apology; the
exquisite coloured plates, produced direct from natural butterflies
by the three-colour process, are a sufficient justification of its
appearance.
The author is a practical entomologist of many years' standing. He
writes from the fulness of a rich experience in the fields. He justly
advocates the "Paisley" method of setting insects. I know it to be
the more expeditious, and less calculated to damage specimens, than
the ordinary process. His notes on the preservation of larvæ will be
welcome in many quarters.
The publishers desire me to express their indebtedness to Messrs.
Watkins and Doncaster, 36, Strand, W.C., for kindly arranging and
lending the specimens from which the coloured plates have been produced.
CHARLES A. HALL.
CONTENTS
CHAPTER PAGE
INTRODUCTORY EDITORIAL NOTE v
LIST OF ILLUSTRATIONS vii
I. THE LIFE-HISTORY OF A BUTTERFLY 1
II. THE CAPTURE AND PRESERVATION OF BUTTERFLIES 13
III. THE BRITISH BUTTERFLIES DESCRIBED 29
INDEX 88
LIST OF ILLUSTRATIONS
PLATE
I. SWALLOW-TAIL--BLACK-VEINED WHITE--LARGE
GARDEN WHITE--SMALL GARDEN WHITE--GREEN-VEINED
WHITE--BATH WHITE--ORANGE-TIP--WOOD
WHITE--PALE CLOUDED YELLOW[*] _Frontispiece_
FACING PAGE
II. METHOD OF SETTING WITH BRISTLE AND BRACES 9
III. "COP" OF 120'S COTTON ON STAND, AND SETTING-NEEDLE
FOR "PAISLEY" METHOD OF SETTING 16
IV. CLOUDED YELLOW--BRIMSTONE--SILVER-WASHED
FRITILLARY, ETC.[*] 25
V. GLANVILLE FRITILLARY--HEATH FRITILLARY, ETC.[*] 32
VI. "PAISLEY" METHOD OF SETTING 35
VII. APPARATUS FOR PRESERVING LARVÆ 38
VIII. RED ADMIRAL--PAINTED LADY--MILK-WEED, ETC.[*] 41
IX. MARBLED WHITE--MOUNTAIN RINGLET--SCOTCH
ARGUS, ETC.[*] 48
X. DARK GREEN FRITILLARY--HIGH BROWN FRITILLARY,
ETC. 51
XI. LARVA OF LARGE GARDEN WHITE--PUPA OF LARGE
GARDEN WHITE, ETC. 54
XII. SMALL HEATH--GREEN HAIRSTREAK--PURPLE HAIRSTREAK,
ETC.[*] 57
XIII. ADONIS BLUE--CHALK-HILL BLUE--LITTLE BLUE,
ETC.[*] 64
XIV. PUPA OF RED ADMIRAL--LARVA OF RED ADMIRAL,
ETC. 73
XV. BROWN ARGUS--AZURE BLUE--SILVER-STUDDED BLUE,
ETC. 80
XVI. LIFE-HISTORY OF SMALL TORTOISESHELL BUTTERFLY:
OVA--LARVÆ--PUPA--MALE INSECT (TO RIGHT)--FEMALE
(LEFT)--FOOD-PLANT (NETTLE)[*] _On the cover_
[*] These eight illustrations are in colour; the others are in black
and white.
BRITISH BUTTERFLIES
CHAPTER I
THE LIFE-HISTORY OF A BUTTERFLY
What is the difference between a butterfly and a moth, and how am I to
distinguish between them? is a question very often put to the student
of insect life--the entomologist.
Butterflies and moths both belong to the Natural Order, _Lepidoptera_,
or scale-winged insects. Butterflies may be distinguished as day
flyers, and the moths fly by night. The main physical difference
between them appears in the forms of the antennæ, or horns; in the
butterflies these organs are club-shaped at the extreme ends. But the
antennæ of the various species do not all follow a common pattern.
In some the knob is abrupt and much smaller, after the manner of a
drum-stick; in others, the thickening commences well down the shaft,
and is gradually increased until it very much resembles an Indian club.
The antennæ of the moths, on the other hand, show much diversity of
form, and in a great many species they are totally different in the
male and female. A very common and beautiful form is the feathered,
or comblike, antenna; another is long and threadlike, and some show
a combination of these two forms; others, again, seem to be striving
after the butterfly type, and approach the club shape. It should
be noted that not a few moths fly during the day, but it is rare,
exceedingly rare, to find a butterfly abroad after sundown. With a
little practice in observation, the novice soon learns to distinguish
between the two.
The stages of development of butterflies and moths are practically the
same: first the egg; next the caterpillar, or larva; then the pupa, or
chrysalis; and, lastly, the imago, or perfect insect.
The eggs of the Lepidoptera are surpassingly beautiful. Are they like
birds' eggs? Not at all! In the first place they are too minute for
comparison with the larger product of the birds; both in colour and
form they more nearly resemble small shells or pearls, as a great many
of them are beautifully opalescent, especially when empty. A good
hand-lens will reveal a great deal of their beauty, but the low power
of an ordinary compound microscope will be necessary to enable you
to see all the nice detail of pattern sculptured on their surfaces.
Each species of butterfly, or moth, produces eggs of particular shape
and ornamentation, so it is quite possible, in most cases, to say to
which species an egg belongs. How long the egg may remain unhatched
depends a good deal upon which butterfly's egg it is, the season of
the year, and the temperature. Not many butterflies pass the winter in
this country in the egg state, that season being usually passed either
as a half-fed hibernating caterpillar, or as a chrysalis; and in a
few cases it is only the female which passes the winter in some secure
retreat, to emerge again in the spring, and then deposit her eggs on
the fresh-growing verdure. But, generally speaking, eggs laid during
the summer hatch out in from ten to sixteen days. And it is well to
be on the lookout for the young larvæ even earlier, if you intend to
rear some species in confinement. If you have secured eggs to rear
from, watch them from day to day to see if they darken, as they often
assume a dark leaden hue immediately before hatching. This is a useful
warning, and serves as a hint to have plenty of fresh food ready for
the young family about to arrive.
The caterpillars are ravenous eaters; you will not notice this fact
particularly at first, because they are then such tiny creatures,
but in proportion to their size their eating capacity is enormous.
They grow at an exceedingly rapid rate and to such an extent that
they literally burst their skins! In a very short time--three or
four days--the old skin bursts and out comes Mr. Caterpillar with a
brand-new one. And this is the manner of their growth; several times
(five or six) this skin-shedding process is repeated. And then the
creature prepares for the last and final change before turning into a
butterfly.
There are one or two more points I would ask you to notice about our
caterpillar ere we pass on to consider his next stage. The legs are
generally sixteen in number. There are six true legs, one pair on each
of the first three body-segments behind the head; four more pairs near
the anal end, and the last segment carries another pair, known as the
"anal claspers." The first six may be said to represent the same legs
in the perfect insect. Note also the breathing holes, or spiracles,
placed in a row along either side of the larva. The head _seems_ to
carry very large eyes, but it does not really do so; the real eyes
are very minute, and it requires a good strong pocket-lens to make
them out. There are twelve of them all told, and they are not all of
equal size. There are six on either side of the mouth, and the three
larger ones on each side are not very difficult to find. The mouth is
furnished with strong mandibles for biting and chewing food, and also
contains the spinneret for the production of the silk used on various
occasions. All these details should be carefully noted--the head, the
eyes, the breathing spiracles, the mandibles, the fore-legs and claws,
and the hind- or pro-legs. Mark the totally different types of feet
which terminate these two sets of legs. You will need to use your lens
for this observation, and to enable you to see the beautiful structure
of the pro-leg foot, it will be necessary for you to examine it through
a compound microscope. It is well for the young entomologist to know
these more prominent features of a caterpillar's economy, if for no
other reason than to be able to answer the questions that are sure to
be put to him on these and many other points.
But only a small percentage of the larvæ that are born into the world
live to become butterflies; some seasons a larger number than usual
may escape, and then we have a butterfly year, but the relentless
ichneumon flies soon restore the balance. They, too, have their young
to provide for, and a strange mode of existence they have. Once you get
to know these ichneumons at sight, you will be astonished at the number
of them. All the summer through you will find them hawking about the
trees, bushes, nettles, and heather, and, indeed, wherever larvæ are to
be found, there, too, you will find these flies. There are many species
of them. Once a female has discovered a larva its doom is sealed. The
ordinary larva has very few defensive weapons; he may wriggle and
squirm and _look_ terrifying, but all the same the ichneumon sets
about her task of placing one or two, and in many cases a dozen or
two, of her eggs either upon or under his skin. These eggs soon hatch,
and the little white maggots pass their existence inside the doomed
creature, eating all the tissues away, at first avoiding the vital
organs, which they leave until the last. When they have reached their
allotted span, and are about to change to the pupa state themselves,
they soon finish off their victim, and all that remains of what might
have been a brilliant butterfly is a little shrivelled bit of skin and
a host of little--or it may be a few big--black, brown, or grey flies.
Sentiment apart, these parasitic flies are extremely useful. When you
consider the large number of eggs laid by a single female butterfly or
moth--from two to six hundred is a fair average--you will realize that
if this enormous progeny were to survive and go on increasing without
any check, the vegetation of the world would very soon prove quite
inadequate to support the vast army of caterpillars, to say nothing of
you and me.
You may at some time find a dozen or two larvæ of some particular
species of butterfly or moth, and at the time of collecting them they
may seem healthy and all right, but weeks afterwards you may discover
that only a very small number will change to chrysalids, the ichneumons
having had the rest. If you can catch and induce a female butterfly to
give you a batch of eggs in captivity, then you may be sure, providing
your treatment of them has been right, that all your brood will arrive
at the perfect state.
The next stage we have to consider we will pass over briefly. The
change from the larva to the chrysalis is always a very fascinating
performance to watch, not that one could sit and see the whole
performance right through from start to finish, the time occupied is
too long for that. Generally the process lasts a day or two, but by
watching at frequent intervals, where several individuals are engaged
at the same operation and each at its own stage of the work, it is
not difficult to follow the whole process of the transformation. Try
it with the larva of the Large Garden White butterfly, perhaps the
commonest, and therefore the easiest to procure; you will gather plenty
of "stung" or "ichneumoned" examples, but still a sufficient number
should be clean to serve your purpose.
We will not enter into all the details of the "spinning-up" process
and describe how an attachment is secured at the anal extremity, and
how our little friend "loops the loop." Some species, such as the
Tortoiseshell, get over this part of their difficulty by omitting the
loop altogether, and therefore hang head downward, suspended only by
the hooks and silk at the tail. Concealment during this stage is the
creature's only hope and chance of survival; other defence they have
none. Their colour may occasionally protect them by virtue of making
them harmonize beautifully with their surroundings. The ichneumons
seldom molest them during the chrysalis stage; but birds and small
animals have sharp eyes when foraging for food, so it is usually far
more difficult to discover these chrysalids than to find the feeding
caterpillars.
The time passed as a chrysalis is very variable; ten days to a
fortnight in summer is sufficient for many species; others pass
over the whole winter, like the spring brood of our common white
butterflies, so that these can be sought for during the winter months
under the overhanging portion of palings, walls, outhouses, and in
similar situations. The cold does not seem to injure them; it may, and
generally does, retard their emergence, and possibly has some effect on
the colours of the wings, but it cannot change their ultimate pattern.
Experiments have been tried with various chrysalids, part of a brood
being hatched out after being submitted to a very low temperature,
and another part of the same brood after being treated with a high
temperature. Speaking generally, the coloration of those subjected to
the cold treatment was brightened and intensified, and Nature does the
same thing in her own way. The early summer butterflies, which pass
through the winter as chrysalids, are almost invariably larger and
brighter than the midsummer or autumn brood of the same species.
But suppose our caterpillar to have successfully run the
gauntlet--ichneumon, bird, beast, and beetle--and to have become
a healthy pupa, and that the time has arrived when he must make
the last and greatest transformation in his short and interesting
career. Several days prior to his exit as a butterfly taking place, a
noticeable change occurs in the apparent colour of the chrysalis.
As a matter of fact it is not the chrysalis shell which is changing
colour, but the developing insect, the colours of which are beginning
to show through it, at first rather faintly; but latterly the pattern
of the wings can be distinctly seen, and the whole body surface gets
darker. When this stage is reached, the advent of our butterfly is not
long delayed. The hour chosen is usually early in the morning, so that
by the time the sun is high and the fresh perfumed flowers are nodding
in the breeze, our little butterfly has expanded and dried his wings,
and is now quite prepared for the beautiful and consummating act in the
wonderful drama of his existence.
[Illustration: PLATE 2
Method of Setting with Bristle and Braces]
While he is drying his wings and preparing for a life amongst sunshine
and flowers, we might spend a few minutes with him ere he leaves us,
and the more so, as now he looks his very best, arrayed in all his
new-found finery. Such wings! no wonder he looks proud as he slowly
opens and closes them, repeating this action over and over again as if
to prove their smooth working before he launches forth upon the air.
And the wonderful pattern of these wings is all built up of tiny scales
placed as regularly as the slates on a roof. Your pocket-lens will
show you much of this, but to examine the individual scales, their
various shapes and structure, you will require a compound microscope.
These scales are the "dust" you will find on your finger and thumb if
ever you pick up a butterfly in such an unscientific manner. You will
notice, too, that the under sides of the wings bear quite a different
design from the upper sides; this is nearly always the case, and in
many foreign butterflies this difference between the two sides is so
very remarkable as to be quite startling in its effect. Well I remember
an old sergeant-major, who had spent many years in India, and had done
a lot of "butterfly dodging" in his day, telling me of this wonderful
effect. He said one would come upon an open piece of meadow-land
blazing with flowers and butterflies, but, on being disturbed, the
whole crowd of insects would rise in the air, and then, he would say,
they looked like a different set altogether. When you capture a few
specimens of any species, examine closely the under sides, and in any
case, if you wish to preserve them, always set one of each sex with the
under side uppermost.
Next to the wings the head claims our attention; it supports three
very essential organs--the eyes, the horns, or antennæ, and the tongue,
or sucker.
The antennæ are undoubtedly the organs of smell, which is perhaps the
most highly developed sense in the Insect World. That the eyes are
a marvel of beauty, and that the tongue is a finely finished little
instrument for its work no one can question; but the sense of smell
has a much longer range than even the eye, with all its facets. And
you will generally find, in relation to the faculty which any animal
or insect has to exert most so as to procure its food and propagate
its kind, the organ of that faculty reaches the highest point of
development and service.
The eyes of the condor and the gannet must be marvellous in range and
penetrating power. I have watched scores of the latter birds sailing
and hovering 150 feet and more above a troubled sea. Suddenly there
would be a slight pause, and then a rocket-like dive right down into
the waves below. To see a fish on the surface from such a height would
be a great feat, but to see and catch one a dozen feet deep in a broken
sea as a gannet can do, is wonderful indeed.
With butterfly and moth the sense of smell is of the greatest
importance. Their vision is good, but short in range; so to find the
flowers wherein lies their food the sight is good, but the power to
detect them by scent must be far better. "Over the hedge is a garden
fair," and if a butterfly cannot see through the hedge, he can at least
smell through it. He could fly over it? Yes, but if his sense of smell
says there is nothing there for him, you see he is saved the time and
trouble; and his life is short.
"Assembling" and "treacling" for moths are two methods employed by
insect-hunters to secure an abundance of specimens otherwise difficult
to obtain, and in both cases it is this same wonderful sense of smell
which is the insect's undoing.
For "assembling," a captive virgin female is taken at dusk to the
locality where the species is likely to occur, and if males are
about they very soon make their appearance. The female being in a
gauze-covered box, they will swarm over it in their efforts to find
an entrance, and when thus engaged can be easily captured. As for the
subtle odour emitted by the lady, you or I could never detect it,
yet these moths come swarming from far and near. I once witnessed a
curious phase of this instinct on a hillside in Arran. My attention was
arrested by a number of males of _Bombyx Quercus_ (variety, _Callunæ_),
keeping near and flying over a certain spot, and, thinking a female
might be about, I went over to investigate. It was a female, but a dead
and crushed one; how it had met its end I could only conjecture; but
evidently, although the insect was mutilated, the scent still lingered,
and brought the males circling round. This large moth flies boldly
during the day, and in Arran the larvæ feed on the heather.
The eyes of a butterfly are large and of the usual insect
pattern--_i.e._, compound, being made up of a number of tiny lenses,
hexagonal in shape, like the honeycomb of the domestic bee. Roughly,
about three thousand of these lenses go to make up the two eyes. As
pointed out, their range of vision is comparatively short, but within
their range vision must be very keen--before, behind, above, and below.
I once saw a sparrow try to capture a Large Garden White in a street
in the town; he darted at it again and again, much in the manner of
the ordinary spotted flycatcher, but the butterfly seemed to have no
difficulty in evading him, and eventually he gave up the game.
A small portion of the eye makes a good slide for the microscope,
but the individual lenses are hardly visible through an ordinary
hand-glass. On the top of the head are one or two small simple eyes,
which do not look as if they could be of much service, but one never
knows, and the butterflies will not tell, although they have long
tongues.
The tongue is a very pretty structure; when not in use it lies coiled
up in spiral fashion like a watch-spring, and is then well protected by
two little side-covers called the "palpi." Needless to say, the tongue
cannot sting. No moth or butterfly has a stinging organ; the tongue
is too delicate for any "cut and thrust" work. It is not difficult to
mount a butterfly's tongue for the microscope, and its examination
well repays the trouble. Particularly noticeable under the microscope
are the little bell-shaped suckers placed in long rows near the tip.
If you wish to make and examine a cross section, take the head of
a freshly killed specimen and extend the tongue in a little melted
paraffin wax; when this is thoroughly set, cut it across in very thin
slices with a sharp razor; place one on a glass slide, then on to the
microscope stage, and there you are! You will soon discover that the
simple-looking tube is a very complicated affair, and quite a little
study in itself.
We will not linger over what remains of the anatomy of our butterfly.
The legs are six in number, but occasionally the first pair are useless
for walking, and only the middle and last pairs are fully developed.
Always remember the maximum number of legs for all insects is six.
Caterpillars may have more or less; they occur as footless grubs with
no legs at all, while some have as many as sixteen legs.
The last, or abdominal, section of a butterfly's body carries the
sexual organs; it is usually more slender in the males than in the
females.