l|iHli?ii

QL iiiiii'*''

I ^63

I S983

J 1904

1 ENT

\

.AjL/t'-e' ^'•L'V-OCa

Protective Resemblance
in the Insecta.

By
MARK L. SYKES, F.R.M.S.,

Vice-President of the Manchester Microscopical Society.

(Reprinted from the Proceedings of the Manchester Field Club).

FEB 2 2 1993

MxVNCHESTER

HINCHLIFFE AND CO. LTD., TONMAN STREEf, DEANSGATE.

1904.

PROTECTIVE RESEMBLANCE IN
THE INSECTA.

I. TJic tJicory of Natural Selection.

The theory of the origin of species by means of natural
selection, first brought before the scientific world by Charles
Darwin more than 40 years ago, is now more or less
familiar to all biologists. It is based upon a few well
known facts ; ist, that the offspring of all animals and
plants are more numerous than the parents : 2nd, that
there is no proportionate increase in numbers of living
things which reach maturity: 3rd, that variations from
the parental forms occur in the young.

Briefly stated, the theory is that the increase in the
numbers of young, whilst the total number of adults
•remains practically stationary, shows that a continual
contest takes place for existence ; that those individuals
who vary in a direction which is best adapted to the
struggle for life, are the most likely to survive, and that
the hereditary transmission of favorable variations, with
changing conditions of life, lead to structural modifications
and to the evolution of new species.

The young of each generation are always much more
numerous than the parents, in all orders, classes and
families throughout the animal and vegetable kingdoms.
There is consequently a rapid and continuous increase in the
numbers brought into existence. Some plants are much
;more prolific than others, but whatever the proportions

184 THE THEORY OF NATURAL SELECTION.

may be the offspring are always the most numerous.
Seeds of all kinds are immeasurably greater in numbers
than the plants which produce them ; in some cases
hundreds of thousands being furnished by a single plant.
In animals also this prodigality of reproduction obtains in
the quantities of ova and of young which are brought into
existence.

An instance of this prolific reproductive facult\' is
found in the common ghost moth [Hepialiis /iiiiiniit),
which deposits upwards of 800 eggs. If it is assumed
that half these ova produce female moths : that these in
turn each lay the same number of eggs and that the
generations be continued for five years without check or
interruption, the fifth generation from a single pair of these
insects would number more than eighty millions of millions
of millions of moths. It has been shewn that if the average
offspring of one oyster could by any possibility breed and
accumulate without hindrance for only five generations
their numbers would be represented by the figure 6 with ^^
noughts behind it, and that the mass of their shells would
be equal to eight times that of the earth.

Notwithstanding, however, the rapid increase of all
forms of life the total number of living things is practically
stationary, and in a case where there may be a temporary
or permanent addition to the numbers of an animal or of
a plant, the increase is made at the expense, and sometimes
at the complete sacrifice, of some other animal or vegetable,
or possibly of both, which would be deprived oi the share
of the room and the food necessary to existence.

There arises, therefore, amongst all living things, a
constant struggle, for life first and for supremacy afterwards,
and this warfare is continually in progre.'-s throughout the
biological world. Every plant and every animal appears to
be doing its utmost to increase its numbers, the struggle

THE STRUGGLE FOR SUPREMACY. 1 85

being the keenest between closely allied, or members of the
same species, as they are dependent upon the same
conditions for the means of subsistence.

In many cases the difficulties of early life are
met, as stated above, by the production of offspring
in enormous quantities, with a better chance of som.e
of them finding a suitable position in which to live
than if only a small number were produced, although the
vast majority cannot possibly arrive at maturity. In
others a comparatively small number only are brought into
existence, but where this is the case the young have
generally advanced further in their development towards
maturity, or are furnished with a generous supply of food,
or are stronger, or otherwise better fitted for the battle of
life ; and, in the case of animals, receive protection through
the guarding care and instruction of their parents until
they are themselves fitted for an independent existence.
But in any case the struggle must take place, the battle
for life has to be fought ; for whatever the number may be
of those which enter into the competition comparatively
few only survive it.

Generally speaking, no two animals or plants are
absolutely alike. Variations are the rule in both the
animal and vegetable kingdoms, and differences of a
greater or lesser degree are found in every species, and
even in the offspring of the same parents.

The causes of variation are not always quite clear.
The fact of the parents being dissimilar will induce varia-
tions in their young, some inheriting features or peculiarities
of either or of both in modified degrees, varying in intensity
and in form. Ancestral characters, dormant in either
parent, may appear and produce marked differences in
the progeny. Through numerous causes new and peculiar
variations may and do arise. "We seem "says Mr. Francis

1 86 THE CAUSES OF VARIATIONS.

Galton " to inherit, bit by bit, this feature from one
" progenitor, that from another .... while the
"several bits are themselves liable to some little change
" during the process of transmission." The conditions of
environment, heat or cold, an absence or excess of moisture,
change of food supply, or any circumstance which affects
the conditions of life of the parent, influence and lead to
variations in the offspring, and these variations may be
transmitted through successive generations.

As animals are generated and produced under mutable
conditions the variations which arise may take almost any
direction. There are limits of course to their extent, as
whatever the differences may be which occur they are
governed and restricted in the individual by the laws of
heredity. But by the same laws, a variation arising in an
individual will probably be transmitted to its offspring in a
modified or intensified degree, the variation itself varying
in the next generation. It may in many cases disappear
altogether, or be so modified as to produce no appreciable
effect either detrimental or advantageous to its possessor,
and may persist in its modified form, or even be emphasized
to a certain extent and still remain what may be termed a
passive variation.

But should a modification or deviation take, and persist
in, a form which is in any way, however little, prejudicial
to the animal or plant in which it arises, it will lead sooner
or later, but inevitably, to its destruction.

On the other hand variations in any direction, whether
of colour, size or form ; keenness of sight, scent or hearing ;
swiftness of foot, of flight, or of swimming ; or which, in any
way, gives the individuals a distinct advantage over their
fellows in the struggle for life, will tend to preserve them
from a fate which the others may prematurely meet. And
these favoured individuals transmitting the advantageous

THE ADVANTAGES OF VARIATIONS. 1 87

variations to their young, some of the latter may possess the
favourable difference in a more marked and pronounced
form than the parents, and these again transmit the increased
favourable variation to their offspring.

There thus arises from these premises, i.e , the facts of
the struggle for existence and that variations occur and
are transmitted from parent to offspring, the inevitable
consequence that those which possess any advantageous
variation in the most marked degree will most surely arrive
at maturity and be able to perpetuate their kind. They,
in fact, will survive because they are the most fitted to do
so. Being better protected against cold or heat, drought
or flood ; provided with better sight or hearing, or keener
scent, or greater powers of locomotion to enable them to
procure food or escape from their enemies ; with modifica-
tions of colour or of form which enable them to escape
detection by their foes, or to lie concealed whilst waiting
for their prey ; it is they who are the best adapted for the
battle of life, for its changing conditions, its competitions,
struggles and difficulties.

And as the conditions of life alter, as environments
change or as migrations to new surroundings and localities
take place, so will the variations which are best adapted to
circumstances be preserved, perpetuated and accumulate
until in the course of time new species, new genera and
new families are evolved, which may eventually be so unlike
their remote ancestors that the recognition of phylogenetic
connection between them may be not only extremely
difficult but even impossible.

The fact that small differences which arise in animals
and plants can be transmitted from parent to offspring, and
that by selection of peculiar features through a succession
of generations they will be intensified to an extreme extent
and new specific characters produced, has been taken

1 88 THE TRANSMISSION OF VARIATIONS.

advantage of by man. Artificial selection of varieties has
long been resorted to for breeding purposes. The judicious
selection and transmission through successive generations
of small individual differences has resulted in the production
of many of the varieties of domestic animals and plants
with which all are familiar.

Nature, with precisely the same effect, has preserved
the favoured varieties in the fact that those animals and
plants which have not been adapted to changing conditions,
or have not been prepared to successfully meet the never
ceasing contest for existence, or which have varied in a
direction unfavorable for the strife, have succumbed ; whilst
their better favoured rivals have survived and been preserved.
In every geological formation which contains organic
remains and in all parts of the world, the unimpeachable
testimony of the rocks supports and confirms this great
truth.

But it must be remembered that although new species
may be the result of natural selection it does not follow
that natural selection shall of necessity always produce new
species. This is evidenced by the persistence of some
forms of both animal and vegetable life through long
periods of geological time, during which little or no
structural modifications have taken place, as is especially
the case amongst some of the lower forms of both kingdoms.

The fact that variations occur and persist which do not
give the varying forms any special advantage has been
raised as an objection to the theory of natural selection.
There does not however seem to be any real difficulty in
the matter, variations do and must take place which are
merely passive or negative, neither advantageous nor
detrimental and which yet persist. The remarkable modi-
fications which occur in the colour bands and markings
on the shells of the mollusca arc indicative of this. In the

PASSIVE VARIATIONS. 1 89

Helices for example the variations amongst some species
are so diverse, the banding and colouring so variegated and
manifold, that occurring in many groups of animals such
wide superficial differences would be classed as separate
species, and even as distinct genera.

So long however as variations in an animal do not
produce any disadvantage, so long, in fact, as they are
merely passive, they may persist and continue to an almost
indefinite extent.

But even when a species has varied in such a manner
and to such an extent that it seems to have acquired, so
far as is possible, complete protection from its enemies and
to be exactly adapted to its surroundings and mode of
living, variations do not cease to take place.

That this is the case is shewn in one of the most
remarkable of known instances of protective resemblance
to natural surroundings ; that of the " leaf butterflies." In
the Kallimce, and many other genera of the Lepidoptera the
resemblance of the wings to leaves when the insects are at
rest is so great as to deceive the most practised and
critical eye. (Fig. 4.) But although the simulation is so
close and the likeness so near, and although all have the
appearance, marking and colours of decaying and dead
leaves the divergence in the individual is very considerable.
"The colour" says Mr. A. R. Wallace writing of the
Kallimcs " is very remarkable for its extreme amount of
variability : from deep reddish green to olive and pale
yellow, hardly two specimens being exactly alike but all
coming within the range of leaves in various stages of
decay."

This divergence in the Lepidoptera is not confined to
the KalliuicB. In the Doleschallice, AncBincB, and in other
cases where protection is secured through resemblance to
environment, and the animal is hidden from its enemies

190

PROTECTIVE RESEMBLANCE.

Fig. 4. Leaf Butterflies. Kallimn paralekta, shewing upper surface, in centre,

surrounded by several species of Kallitiice and Doleschaltice with the wings folded

and shewing leaf like markings of under surfaces.

by being lost amongst its surroundings when at rest, the
deviations in markings and colours are often considerable,
and the variations in a single species are sometimes as
great as between members of different species.*

*Variations are also found in numerous species of the inedible Dnnainw, Heliconina',
&c., and are repeatedly referred to by writers. Bates for instance says that Mechnnitis
polymnia " varies not only in general colour and pattern, but also very considerably in
'' the sliape of the wings," and again of Hflicoiiiiis iiumata " the species is so variable
" that it is difficult to find two examples exactly alike, it varies in structure as well as in
"colours." Wallace also desciibes Ceiathiin ninonia (illustrated in fig. 8, No. viii.)as
"another of those very mutable .species, exhibiting many local varieties," and Shelford
says " the females of Eurypus halithxivses are extremely variable, in fact no two
" specimens of the five series of this species in ' the Sarawak (Borneo) museum collection '
"are exactly alike and almost every specimen deserves a varietal name ol its own. '
" Ten distinct varieties are described '' writes Bates of Heliconius melpomene " all more
" or less connected by intermediate forms."

THE COLOURS OF INSECTS. 19.I

II. TJie Colours of Insects.

The most striking feature of the Insecta is the extreme
brightness and diversity of colour which they display, in all
the orders into which they are divided. In no other class
in the animal kingdom are such remarkable brilliancy and
variety to be found. Even the birds, the most beautiful
and charming of the vertebrates, cannot rival them in this
respect.

All the orders of insects share in this pre-eminence of
beauty, but it is the Lepidopto a, the great order which
includes the butterflies and moths, that can claim to be
the most wondrous animals in the world for brilliance of
colouring and diversity of marking, and that far outshine
all the other animals in their display of elegant adornment.
No colour or pattern seems to be impossible, no contrast
of hue unsuitable or discrepant, and no harmonious or
fantastic marking unattainable, amongst these frail and
delicate creatures. Brilliant metallic blues and greens,
luminous crimson and gaudy red, bright orange and yellow
and lustrous shining white or deep black, resplendent
silver and refulgent copper, all possible combinations of
colour, gay and luxurious, of every hue and tint and shade
are found in a thousand combinations in the butterflies
and moths.

Not in colour only are these insects remarkable ; their
patterns and figures are as varied and beautiful as the
colours which they exhibit. Perfect symmetry is almost
universal amongst them, although the markings may be very
elaborate ; the finest lines and curves and tracery of
ornament being displayed with almost geometrical accuracy
and the more minutely the details are examined the more
perfect they appear to be.

In many cases, as in the Heliconincs, the bright colours

192 MARKINGS, AND COLOUR CONTRASTS.

appear on both upper and under surfaces of the wings and
the markings are nearly the same on both sides. In others,
as in the Callicorince, Catagravunime, Sac, ahhough the
insects are extremely brilliant and richly coloured on both
the upper and under sides, they are quite different in both
design and colouring on the two surfaces of the wings.
Sometimes the display of colour appears only on the
upper surfaces, as in the gorgeous MorphiiicB, Ornithopterce,
Papilionincs, &c., which are luxuriously adorned in iridescent
blues and greens, crimson and orange, with combinations
of other colours equally attractive to the eye, whilst the
under surfaces are comparatively dull and inconspicuous.

In others of the Lepidoptera the upper surfaces of the
fore wings are much less highly coloured than those of the
hind wings, for instance in the Catocalce and many other of
the diurnal moths ; which rest with the upper surfaces of
the wings exposed, the grey fore wings folded over and
concealing the brightly coloured hind wings.

On the other hand there are thousands of species of
butterflies and moths the appearances of which are quite
the opposite of those considered above. In place of the
gay and showy colours they are clothed in subdued grey
and drab, dun and umbre and dull brown, nearly uniform
over the whole surfaces of the wings, almost without
pattern, or marked with few and generally inconspicuous
and often obscure spots and bands. Many again are of a
greenish hue, or mottled in green and grey and are seen
indistinctly, or perhaps not at all, in the obscurity of their
natural surroundings.

III. Insects as Food for other Animals.

The increasing ratio of successive generations of insects
is so great that were it unchecked and all the young

CHECKS TO NATURAL INCREASE. 1 93

animals allowed to arrive at maturity, their numbers
would quickly be such as to make the earth uninhabitable ;
as there would soon be neither food nor room for
themselves, much less for other animals. The increase is
checked however in many ways. Extremes of temperature
and climate, dearth of food, disease, fungi, and bacteria
destroy countless numbers of them every season. They
serve largely as food for other animals which could not
themselves live if deprived of the abundant supply
furnished by the surplus progeny of the insecta.

Many insects feed upon others, the larv;e of one living
in and upon another, as in the case of the Ichneiniwnidce;
the perfect forms consume the larvae and pups of
other species and often feed upon the imagines of other
kinds.*

Birds subsist largely upon insects in all stages of their
metamorphosis, many living almost entirely upon them and
destroying incredible numbers. Frogs, toads and lizards,
feed upon them, as do also the monkeys and many other
tropical vertebrates. The soft and juicy larvaj are particu-
larly attractive morsels to the Insectivora, the fat grub and
unctuous caterpillar being eagerly sought for in every crack
and crevice in field, hedge and wood.

That insects constitute a staple part of the food of
other animals is very well known to every naturalist.
Many experiments have been made with the object of
testing the selective faculty and appetency of animals in this
respect ; especially by Professors E. B. Poulton, Lloyd-

*The word 'imago' as representing ihe final stag'e in insect metamorphosis is
objectionable and its plural 'imagines' is particularly so. It was used by Linnjeus, as
he says, "because, having laid aside its mask and cast off its swaddling bands, (the insect)
■' being no longer disguised or confined, or in any respect imperfect, is now become a true
" representative or image of its species and is qualified to fulfil the laws of nature in
"propagating its kind " — Mr. J. T. Lingard suggests instead 'matura' (matiiro '=■ to
ripen) " as it would indicate at once the state reached, whilst its termination, both singular
"and plural, would accord with both larva and pupa. " I quite agree with this happy
suggestion and shall be glad to sec itadopied to represent the perfect msect. INI.L.S.

194 PROTECTION BY THEIR NOXIOUS QUALITIES.

Morgan, Romanes, and later by Mr. Guy A. K. Marshall :
and the works of Belt, Bates, Mliller, Wallace, Swinhoe,
Trimen, Butler, Beddoe and many other well known
naturalists bear indisputable testimony to the fact.

So many and so persistent are the enemies to insect
life that even with the prolific reproductive capabilities
which insects [)Ossess it is almost a matter of surprise that
so many survive. The liability to attack and destruction
appears to be greatest in the case of those which are highly
coloured and conspicuously marked, and more especially
in the showy and brightly adorned Lepidoptera, which appear
to be so entirely defenceless against the attacks of their
numerous enemies.

It is known, however, that many of these highly attractive
and brilliant butterflies and moths possess some peculiar
repellent feature. Many of them are highly scented, others
are tough, dry and hard, some exude nauseous and evil-
smelling secretions, and bitter or acidulous fluids, whilst
others are clothed in part with irritating hairs and loose
fluffy scales, which render them disagreeable and offensive
to the insect-eating animals.

Amongst the attractively embellished and gaily adorned
butterflies are the HeliconiiKX, Danaincs, AercsincB, and
Etiplceincs, all of which are beautifully coloured and
conspicuously marked. Their wings are often nearly alike
on both the upper and under surfaces. They seem to
have no sense of fear or avoidance of danger, fly without
regard to concealment, and rest in any exposed and open
situation. But it is known that they all possess in one or
other form that repellent feature which renders them
distasteful and obnoxious to the Inscctivora. "They all
"have juices which exhale a powerful scent" said the late
A. Milnes Marshall. " This odour is not very offensive to
" man, but it has been shewn by experiment to be so to
" birds and other insect-eating animals."

PROTECTION BY CONSriCUOUS COLOURINGS. I95

It is here where the value of the adornment is shewn
Being brightly coloured and easily recognized they cannot
be mistaken ; and the shining blues and crimsons, and gay
reds and yellows serve as danger signals, warning colours ;
notifying by an easily recognized sign that the wearers are
inedible, thus affording them immunity from attack and
safeguarding them from destruction

All observations shew that young animals have no
instinctive knowledge as to what is good for food and
what should be rejected, but that it is a matter which must
be learned either by instruction or by experience. There
is no intuitive acquaintance in the selection of edible
material.

Professor Lloyd-Morgan in his work " Habit and
Instinct" records the results of a large number of experi-
ments which he made with the object of satisfying himself
upon this question by personal observation. He says
his experiments were conducted with the sole object of
ascertaining if there was any instinctive avoidance of
distasteful, or selection of edible, material, and of this he
" never found a single instance." " There can be no
" question " he says " that experience plays its part
" and practice makes perfect." " That which is outside
" experience can afford no data for the conscious guidance
"of future behaviour." Mr. Guy Marshall's recent experi-
ments with monkeys, birds and other animals in South
Africa all point to the same conclusion, as do those of
Professor Poulton and other observers.

Nor is the lesson long in being learned. A nauseous
black and yellow banded larva, or a bitter, crimson winged
moth, a beetle which on being disturbed exudes a nasty
fluid, a yellow hornet or a stinging bee, are very quickly
recognized by a young bird which has once had experience
of its objectionable characteristic, and it is amusing to
watch the emotions of a young animal which is placed in

196 muller's theory of :\iutual protection.

the situation of repeating a recently learned disagreeable
experience of this nature.

Bright and conspicuous colours in insects are then a
source of safety rather than of danger, and the more highly
a distasteful caterpillar or butterfly or beetle is adorned,
the more easily and quickly it is recognised when once its
inedibility has been tested, and the greater will be its
chances of escaping destruction.

IV. Mutual Protection : Miillers theory.

There are in many parts of the world a number of
highly coloured and inedible butterflies of entirely
different sub-families and genera, which are so similar in
outward appearance, markings, colours, shape of wings and
peculiarity of flight that they may be very easily mistaken
one for another.

A considerable number of cases are known in which
two entirely different butterflies, or a butterfly and a moth,
exactly alike in appearance, are found flying in concert, or
in the same locality. This similarity is often seen between
three or four different kinds, and occasionally within a
limited area there are found six or seven or even a larger
number of different species of butterflies, of two or more
different sub-families, in which the likeness of each to the
others is remarkably close ; and the probability of mistaking
them is especially great when the insects are on the wing.

It was for some time a problem to students of this
branch of biology why this superficial resemblance amongst
the inedible Lepidoptera should exist, and the explanation
which is now accepted is due to the observations of Fritz
Muller.

As the young insect-eating animals have to learn by
experience what food to select and what to avoid, there
must be a certain number of the inedible insects attacked

INSTANCE.S OF PROTECTIVE SIMULATION.

197

■^ •^ En

rt

C «

S .y

l-^i

2 S 5 «• ^ . ^

<1s

•1 S §< ?^ s

^ tjq (i; c/^ PQ tiH

u C

u S

1^^

20
Danaina
Meluuva.
Egina.
S. Ameri
Lower A
Male.

C oj rt

^ -; S

«

5 Sl - ^

^ « - ■?, •
c^•S '^ 5 ^ ^

■a ?i Q c . ^

N ^ 5: C . ni

S. A
Para
Fem;

Dan(
Titlu
Han
S. A
Para
Fem

r: . s .y =3

S "~ <U qj ^ 'li

as .s « -S 'z'Z

Helicot
Helico)

Messen
S. Am
Colom
Femali

I
Danai.
Melim.
Messen
S. Am
Colom
Male.

W

^ i g ^

. ~ s t'5

"^ ^- j; £

ro's'S «•< Sii

00 5^ <^

^ g 5 .J; <; c a:

Helico
Helico

Zuleik
Cent.
Hond
Fema

Dana.
Callit.
Hezia.
Cent.
Hond
Male.

Helicc
Eucrc.
Cent.
Rio J;

Fema

fe

^

1)

c3

cS

s

■<

H

*kH

'S

0) .

.i.s.i^

? :^ .:^ . Ts 13

M S p? ■•n .:

- lilt's -1

W
Q

Helic
Tela
Cent
Honi
Fem

Datu
Meli.
I in ill
Cent
Hon:
Malt

Hclu

S . &
Colo
Fem

CO

: .« •:

■j: « :? S — •
5 -? -^ <; 'S i:i

?» :? t* S S

•-1
.8

.i

•J-

<

ij

^

5

!3

.Vo

,%j

V

ci

1

^

1

<

Si

Oh

a.

C

j: < c^--

15J

ci

~ ~ 53 OJ 1)

.52^ = 51

5 -.5 -c^-^ S.ii

Ijh -/:■ O cAi E tJ c/;

- D " c: < o w
Ph -v; O X K 1-3 c/:

<

C3 Z

^3x

„ ^ - .. < q w
Pi 7: O CA) K p-J c«

O "" ,■■ • <f X -^

- D (« (1h>2 q (d

Ph Cfi O C/3 K 1-5 C/2

198 INSTANCES OF PROTECTIVE SIMULATION.

and destroyed before the lesson is acquired. The closer
this resemblance between two or more species, the more
probably will one be mistaken for another ; the number of
each kind sacrificed to inexperience will be reduced, and
the amount of protection afforded to the different species
will be greater as the total destruction will be divided
amongst them ; for a young bird, for instance, having
experienced the nauseousness of one of these attractive
and easily recognized insects, will avoid attacking another
of similar appearance, although it may not be of the same
species or even of the same genus.

Many of the Heliconi?up, for example, of different species,
are very similar in shape, marking and colours ; and there
are often found in the localities which they frequent several
different species of the Danaince which very closely simulate
them in every way. A few of these are illustrated in
Plate III. There are shewn ten pairs of butterflies, each pair
(one insect above and the other beneath it) very closely alike
but of different sub-families, having no relationship whatever
to each other. All the insects shewn in this plate are
highly coloured and strongly marked in black, orange,
yellow, brown and white, and are large and strikingly
handsome insects ; all are known to be distasteful to,
and avoided by, the lusectivora and they afford an
interesting series of examples of the mutual protection
due to simulation and superficial resemblance in inedible
insects.

Tropical South America, where Miiller made his
observations, is rich in producing, from numerous regions,
instances of this kind of protection in butterflies. In
Honduras there are found several species of HeliconincB and
Daiuxincc each of which resembles the others. The fore
wings are coloured a deep sepia, almost black, with white
or pale yellow spots, the hind wings being light chocolate
with lines, spots and borders of sepia (Fig. 5). In the

PROTECTIVE SIMULATION.

199

Fig. s- Heliconin^ and Danain.^. (Honduras.)
I. Heliconius zideika. 2. Thyridia melantho.

3. Eiieides thyana. 4. Tithoren irene.

5. Cctllithomia hesia.

same region of South America there is another group
of butterflies of the same sub-families but quite different in
appearance from those named above. In all these the
ground colour of both fore and hind wings is a bright

Fig. 6. Heliconi.m.e and Danain^e. (Honduras.)

I. Heliconius telchinia. 2. Lycorea atergatis.

3. Melincen imitnta. 4. Etteides dynnstes,

5. Mech.mitis doryssits.

200

PROTECTIVE SIMULATION.

brown with strong sepia bands and margins, and the fore-
wings are in all cases marked with spots and bands of clear
pale yellow (Fig. 6). In Bolivia and the upper Amazons
there is another series entirely unlike either of those
already described. The prevailing colour is black with
clear lemon-yellow spots on the forewings, the hind wings
being strongly marked with bright crimson radiating lines ;
the group being a handsome and conspicuous one. Four
of these butterflies belong to the Heliconina; and the last to
the NyinphalincE (Fig. 7). An even more remarkable group

Fig. 7. Four Heliconin.e and Ona (No. 5) Nymphalid, from Bolivia.
I. Heliconhis venestus. 2. Heliconhis vesta.

3. Eueides thales. 4- Eueides heliconides.

5. Eresia corneha.

is seen in Fig. 8 which illustrates eight simulating
butterflies from Brazil, each of which might very easily be
mistaken for any of the others if seen alone; yet all are of
different species and belong to three sub-families, including
the HelicoiiiuiC, Danaiiuv and Picriiue.

Instances of multiple protection, due to resemblances
between inedible butterflies of different species and genera,
although so abundant in the neo-tropical regions are by no
means confined to that part of the world. In the eastern
hemisphere they are both numerous and diverse in
character.

TROTECTIVE SIMULATION.

lOI

In Africa several species of the Danaincr and Acnrina;,
two entirely different sub-families, with very marked
superficial likeness, are found flying in company or

Fig. 8. IIrmconin^ and DanaiN/E from Brazil.

I. Lyroi-pn hnlia, II. Enrides dyaitnsa. III. Helicoiiiiis etirrotp,

W. Mcchimitis lysininiii, V. Hresin sf>., VI. Mrchnnitis nfsea,

VII. Ci'i-tttinia mpljtliis. \'III. C. niuonia,

in the same localities, the ground colours of the wings
together with the chocolate or black and white spots
making them very much alike ; and in some of the Danaimc
and Lyccpnida' and also between certain Acnriiio' and
NyvipJialitio' a similar portraiture is found.

Many of the different genera and species of the
Acnmiue exhibit these mutually protective features to a
large extent. This sub-family is widely distributed over
the continent of Africa and possesses the repellent features
of the Danaiiuv : the resistent vitality of its members is very
high and they are strongly marked and easily recognized
insects. Most of them are of a fulvous colour, promi-
nently marked with lines and bands of dark brown and
chocolate, sometimes dashed with white, and many are
dotted with conspicuous dark coloured and black spots

202 BATES'S THEORY.

and lines and patches ; their wings are rather long and
narrow and they bear an easily recognized and common
likeness. Fig. 9 illustrates a pair, ^ and ^ ,of Acrcsa acara
from East Africa, together with two, $ and ^ o{ A. Natalica

Fig. 9. ACR.^IN^, (Africa.)
Acra-a acara i Acvcea acai-a 9

A. NataJica i A. Natalica ?

from the same locality ; the prevailing colours, markings,
spots, shape, and general appearance being remarkably
alike and beautiful.

V. Mimicry or Sinmlism : Bates's tJieory.

It is to the late H. W. Bates that we owe the term
• mimicry ' in relation to insects. The word is rather
unhappily chosen as it implies conscious and even voluntary
imitation, which certainly do not exist in the insect world.
It has however, been in use so long that its intended
significance is generally recognized amongst entomologists

SIMULISM A MORE EXPRESSIVE TERM. 203

and other biologists, although it is misleading to those who
are less intimately acquainted with the subject.*

Edible insects are found in all orders and families, and
their best means of protection lies in concealment or in
some method of deceiving their numerous enemies.

There are amongst the butterflies and moths many
edible species which are quite brightly and gaily coloured,
with markings on the wings almost as emphatic and
distinct as those of the DaiiaiiuE and Heliconince already
considered. In all regions where the inedible Lepidoptera
are found, there are also found certain edible butterflies and
moths which bear a strong superficial likeness to them.
The distasteful HelicojiincB dixxd Danaincu oi Sowth. America,
the Danaince and AcrmncB of Africa, and the DanaincB of
Asia, are copied and simulated in many cases by edible
Lepidoptet'a, which are so like them in every way that even
collectors sometimes fail to distinguish between them.

The edible mimics or simulators are found in all
families of butterflies from the PapilionincE downwards
through the Nyinphalincr, Pierince, and so on, to and
including some of the diurnal moths ; the resemblance
extending to colour, size, shape, peculiarity of flight and
habits of life. The similarity is often so close that the
insects themselves are sometimes deceived. Fritz Miiller
says "I have repeatedly seen the male (mimicker) pursuing
" the female of the mimicked species till after closely
" approaching and becoming aware of his error he suddenly
" returned."

The simulation is not however confined to butterflies
and moths ; for not only do some of the Lepidoptera

*The word 'mimicry' has always appeared to me to be an unfortunate one for the
reasons stated above. I would suggest in preference the word ' simulism ' as being
much more suitable for e.xpressing the superficial resemblance of some insects to others
or to their environment and as avoiding the implication of conscious imitation.
'Simulism,' 'Simulation," 'Simulating,' &c., seem to me to be at once expressive,
explanatory and euphonious, and to be free from the inference of designed and cognitive
resemblance. I have adopted this nomenclature in this paper. M. L. S.

204

SIMULISM OF PAPILIO MEROT'E.

resemble wasps, bees, beetles, and other insects, and even
some of the small tropical birds, but some beetles are like
insects in other orders, flies have the appearance of stinging
Hymenopterts , and indeed this copying or simulation is
found to occur in all orders of insects.

Amongst the most remarkable of the simulating
Lepidoptera is the African Papilio merope and its varieties
of females. P. merope is found nearly all over the African
continent, and it is singular that not only are all the various
females entirely unlike the males, but that the sexes are
possessed of quite different means of protection.

I'lg. lo. Pafiilio )iirro/>c, St ^t '"^-'st on U-.'il ot .-m AtVican <frass.

SlMULIS^r OF I'APlLtO MEROt'E. 2o5

The wings of the male jnerope are of a creamy white on
the upper surfaces, with black markings which are of
somewhat different patterns in the several varieties of
the butterfly, and all possess the characteristic " tailed "
extension of the hind wing found in the PapilioniiKZ. The
undersides of the wings are also of a creamy white colour
with various brown markings and lines of different shades.
When the insect is at rest the wings are folded over the
back, the under sides only are exposed, the darker shaded
hind wing being only seen, and the insect presents a very
close appearance to a broad leaved grass, to the faded ends
of which the butterfly habitually hangs suspended with the
wings hanging downwards. (Fig. lo)

The numerous female varieties of P. inerope (Fig. ii)
are very diverse in different localities, and have deviated
not only from the shape, size and colours of the males to
which they bear no resemblance whatever, but from each
other ; and have acquired in the respective regions in
which they are found the appearances of various species
of the inedible Daiiaince. (Fig. 12.)

In the Cape the female of P. inerope is similar to the
type form of the Danaid, Aniauris ecJieria, with black wings,
all of which are spotted with yellow and marked with a
large yellow patch on the centre of each hind wing. In
Natal the female nierope var cenea is like a local form of
A. ecJieria var. albimaculata, which differs from the Cape
type, the spots on the fore wings being white instead of
yellow. In East Africa the female merope again varies in
tipiUus and assumes the type form of Aniaiiris niavttis,
which is a black butterfly marked with large pearly patches
on both fore and hind wings. There is also found in Natal
another variety, Jiippocoon, which simulates the southern
form of ^. niavius, vi?.., doininicamis, on the wings of which
the pearly patches are much larger than on those of
inavius. In the Cape again there is still another even

206

SIMULISM OF PAPILIO MEROPE.

more remarkable but rare form of vierope var. trophonius,
which is closely similar to the brown and chocolate with

Papilio nierope :
type and varieties ot
9 simulating African
Danaince.

I. Type, upper

(right) and

under (left)

sides.

n. Variety cenea.

III. ,, tiptdus.

IV. ,, hippocoon.
V. ,, trophouiiis.

Fig. ti.

IB^

Danaince, of Africa,
simulated by 9 vars
ot Papilio tnerope.

Ia. Ainatiris I'cheria,
upper (right) and
under (loft) sides.
IIa. .'/. criteria, var
albimactilafa,
HIa. a. ftiaviiis.
IVa. a. dominicanus.
Va. Limnas

chrvsippiis.

4

Fig.

SIMULATION OF LIMNAS CHRVSIPPUS. 207

black and white markings and spots of the well known
Danaid Livinas chrysippiis. All these species and varieties
are illustrated in Figures ii and I2.

Another instance of the tendency of unprotected
butterflies to follow varieties which may arise in a protected
species, occurs in the several female forms of Hypolininas
niisippiis, belonging to the sub-family Nymp]ialince.

The Danaid, Linmas cJirysippics, already referred to, has
a very wide geographical range, extending over the whole
of the African continent, Southern Asia and into the
Malay Peninsula and islands. The colouring of the type
is a yellowish brown deepening into chocolate on the fore
wings ; the bodies are black with small white spots, and the
apices of the fore wings are black with large white spots
across. In East Africa there is found a variety of the
female, (var. dorippics), in which the chocolate, black and
white of the fore wings do not appear, all the wings
being of a light ochreous brown with very dark brown,
almost black, margins. In West Africa, in another female
variety of this butterfly (var. alcippus), the fore wings are
the same as in the type, but the hind wings are suffused
with white. At Aden the type of cJirysippiis and its two
female varieties are all found.

All these varieties of chrysippus are simulated in the
above regions by females of the Nymphalid, Hypolininas
misippus. The male of this butterfly is black, with a large
white patch in about the centre of each wing, the patches
being bordered with deep shot blue. The females are
however quite dissimilar. In nearly the whole of the great
area over which the type female of Lininas chrysippus
ranges, it is simulated by the female of H. misippus, the
brown and chocolate with white and black markings and
margins being closely copied. But in some localities
where the dorippus variety of chrysippus occurs, the female
misippus varies also and resembles it, and in var. inaria the

2o8 SIMULATION OF LIMNAS CHRYSIPPUS.

chocolate white and black are absent and the comparatively
uniform colouring of dorippus is assumed. In other areas
where the female cluysippus takes the form of alcippus, the
female of H. viissipus also varies in the same direction
taking the form alcippoides, the hind wings being nearly all
white, whilst the black and white of the fore wings are
retained. The types and varieties of these butterflies are
illustrated in Plate IV.

H. inisippus is not, however, confined to the regions
where L. cJirysippus is found. The type form of juisippus
is established, for instance, in some parts of tropical South
America and in the West Indies, where chrysippiis does not
occur. It may perhaps be assumed from this fact that the
protection which these two species derive from mutual
resemblance is due, where it occurs, rather to the Mullerian
than to the Batesian form of simulation.

Of L. chrysippits there are simulating butterflies in
many of the localities where it and its varieties are found.
One of these, Argynnis nipJie, from Burma, is illustrated on
Plate IV. The upper surfaces of the wings of both male
and female are a rich golden bronze colour with deep black
spots distributed over their whole area. In the female,
however, the apices of the fore wings are black with white
patches and spots, and the insect bears a strong resemblance
to the female chrysippiis, for which it might easily be mistaken.

Salatura genutia is another of the brownish yellow
Danaince which has a wide range in the East. This
butterfly is marked with broad black lines which follow
the neuration of the wings, the tips of the fore wings being,
like chrysippiis, black, with white patches and spots. In
the same regions, India, Burma, &c., is found another
butterfly, Elymnias itudiilaris, the female of which is verj'
similar togcuutia in colours and markings, although the latter
are not so close as in the two cases last referred to. (See
Plate IV.) It appears to be an instance of a transitional

INSTANCES OF SIMULATION.

209

« -S •« -^ K." § S

^ <i '^ 'K :^ 'cri ''^

<r' F' rs

^ >l5 '^ "^ s; c/: '^

I 14

S -S ■§ cT § "tS
Qi c^ !^ u:; Ph ;i

5 u

• — • ci

t/:.|

'■'> [5 "2

• — ■<'

>

iiaiii(i\

It It as.

rysippt

ripptts

Africa

en.

ci

^ <: •« ^ ■ "^

1;

;i;

0) s ^ "-. ;^ <!

H

<

J

o

^ ?i

u

>,CQ

£0

LO

s ^

-^ ci

u §

^-H

■.-1

'•N.

^
.«

■S'J

.13 3 .

^^

<^^

U

Daitaiiin .
Li lit It as.

Chrysipptts

1-

l-i

III

cT c3

1-

^E

iiijl

« •;; -5 c: "P

Q s C) < d

2

1 M 1 i 1

OJ^ ►> rt 3 u

6

p

6

^

■y,

^

^

c3

~

cz

~

>i

^-,

ts d

y.

rt

7:

. — , .,

d

r 'S

.^

. .

cT

"3

~ rt

3

^

1

.5 «

1

0^

^ ^=1: :^ a « 2

lit

5l

_1J

s

ill

\-i

ri

j3

^ W Z 2:

i; 3 w -v' <

< -

H -J

^ U X
Q td

< -

5 o X

;5 Z ii

^ i ^ ." 5 U X

^;i D w e: < o (d

piH oi O X -i- 1-5 CO

fe cA! O cc S hJ en

210 SIMULATION OF DANAIN/E.

stage, where the female is departing from the ancestral
purplish black and brown, still retained by the male, and
acquiring a close resemblance to the protected Danaid.
This species is further interesting in the fact that the under
sides of the wings of both males and females are marked
and coloured very much like brown and withered leaves, to
which they bear a close resemblance when they are folded
and the insects are at rest.

There are found in Africa, India and many parts of the
Oriental regions a large number of butterflies belonging to
the DanaincE which are of a general black or very dark
brown colour, variously marked with yellow, cream, or
pearly-tinted white : large and handsome insects, more or
less similar in general appearance. They are very plentiful
in the regions where they are found, are slow-flying and
apparently fearless insects, are possessed of the toughness
and nauseousness which characterize the Danaince and are
generally avoided by the birds, monkeys, lizards and other
animals whose food consists partly or wholely of insects.

Amongst these DanaincE are Atnanris niaviiis, A.
doniinicanus, and A. ecJieria, already referred to, with other
species such as A. inferna, A. ocJilea, and A. damocles ; and
associated with them are a number of other butterflies of
the sub-family NyviphalincB, including several species of
Euralia, Hypolimnas, Psendacrcea, and other genera, all of
which closely resemble the various Danaince in the company
of which they are found. There are also seen in the same
regions others of the Danaince of somewhat similar
colouring to those last named, but with the markings more
in the shape of broad lines and spots than in large
patches of colour. Included in these are several species of
Paralitica, which have a wide distribution in India, from
Assam to the south. The simulators of these butterflies
are found in several sub-families, including the Papilionince^
Nymphalince, Pierince, &c., and even amongst the moths.

INSTANCES OF SIMULISM.

211

o .-^

rt rt o

? 2 1 c^-

-S-^ "3

^> 5^

£hS

c;56ci^

<-^

;.«U

■;:-^-s .2^

S S ■ ^ .

Sll^

-|..|^■S ^ -1 -^

k)^G^£;i:

t<jn;^^;5g

cj _0 g

r" '"^ ' rt

5 S~ Tj

•5.2 S ►S

>

H

Danat
Paran
Aglea
India,

N. W.
Male.

Paran
Macar
India.
N. W.
Male.

hJ

PL,

fe

o

u

,^

_ ^

i

12

^' S c

VO IJ

o

1— 1

H

Ciai
eyloi

pu,

2 -ii O .

s 'S 5

Danah

Panmt

Aglca

India, i

Ceylon

Male.

•2 §:^ . P ^
^ js :-. :« p 5

Q

i£

'"- .'^

« -S;

t> r?' ^

,5 Sii

^ « C^ ii M "

• 5^3

ie e « 9^ dJ
^ o' ^* . ^ ^-

-§^ ^ -S c« t; =s

« ?,.3 !;iii

^cA'^

— ■

5

-ij

.. ^ •<>

S'S^t .

:5 Q'&

Q t/1 s^

~ c> 5 .1)

■o* v! ^

A/elan
Throu
Bomb;

Pterin

Metap
Agatlh
India.
Assam
Femal

Danat
Paran

Aglea
Indian
Sikkin
Male.

Nynip.
Hestin
Nam a
Indian
Sikkin
Male.

« D a c:

3 "^
-8^

Q a

<

~ D ■■

2ux

;iHC/30cnKh-)-X! [iic/}Oc/2KhJcfi fec/iOoiEt-J:/: Ci<cfiOc/3Ki-3c/3

212 NAUSEOUS EUI'L(KIN/E.

An examination of the figures in the illustrations (Plate V.)
will reveal better than any description how close these
resemblances are.

The Enplceince have not so wide a geographical range
as some of the Danaince, being confined to the Oriental
and Malayan regions, but they also are characterized by a
repellent nauseousness, which gives them considerable
immunity from attack and destruction. They are an
exceedingly handsome sub-family, many of them having
large black wings spotted and lined with white, and strongly
suffused with a very rich deep blue, which varies in different
angles of light, as shot-silk does, and which sometimes
spreads over nearly the whole surface of the wings,
giving the butterflies a superb and exceedingly attractive
appearance.

The Eiiplceince consist of numerous genera, including
Trepsichrois, Stictoplcea, Danisepa, Crastia and others.
Numerous species in these genera are simulated by
butterflies of several sub-families, including the Papilioniucc,
NymphalincE, Elyinniiiue, &c., and by some of the Clial-
cossime and Bombyciiuc amongst the moths.

On Plate No. VI. are illustrated three pairs of the
Euplcemce ; TrepsicJirois Linnei, from northern India, with
three pairs of mimics, Elyvinias leucocyina, Isamiopsis
telearchus, and the moth Calaniesia uiidama, all of which
bear the closest resemblance to the Enplccime. On the
same plate are also shewn two females of another Euplcra,
Stictoploea binotata, with their simulators Dyctis patnoides,
and one of the Papilios, Isamiopsis Slateri. The similarity
is in all cases very striking, and it is remarkable that in the
first three cases mentioned above the males and females of
both simulated and simulating butterflies differ from each
other in each species, but are in all instances similar to
the respective males and females to which they bear so
near a resemblance.

INSTANCES OF SIMULISM.

2n

,~ r»- '"i ^ "• 5

tjq S, <) ►i^ <; Uh

^ S '^ ^ -^ ^

^-* -o :^ ^ ^

kJK >C5 H^ -< ;

=Cl Cj -^ ^ < ;i.

. o
5 c3-

kj f> 1^ ►S

<)►:= -<S

r:: ~ '3 d '^ (u

ki c^^^h5-<P%

cq lo -? k5 < P=;

.?: "-^ :;. ^-*

J? -ci =: ^ ='•■ ^
.~ ■'^ •" >^ n "J

ki k)<i j:: u: :i.

•^ C* •^ r^ D

fO ^

':;**. ^^ "— '

5 S S '^

"ii «

5. .^ HH

:-. .« :5 HiH

:? ~ Q

■|^> n

5 S &* . rt

■s^« .

tlph
reps
initt
idia,
hasi
ale.

5 S 5.5 -J -J

•§ -2 "^.2

k] f^ •-^ ►:; u; ?;

kj k^ <i h= u; :<

kji^c?^

5; '.> ^ r^ ^ cj

r^^^<3 >: -S 5

kjC^c^^-lu.

~ D " e: ^ O a

fi< C/2 O y) K hJ CO

— 55 =5 u V

r; 3 w s; < o w

p!H c/} O c/2 53 1-1 c/)

z <

'^ ;2 i^ >:< q a
Ik cfi O c/} ►^ hJ CA!

■" ^ "^j . 5 ^ ;<

fe 72 O C/2 K i-J C/2

214

WING SCALES OF LEPIDOPTERA.

The wings of the butterflies and moths are composed
of a double membrane, itself transparent and colourless,
but covered on both the upper and under surfaces with a
great number of minute feathers or scales. It is to the
colour and arrangement of the scales that the brilliancy
and variety of the wings are due. The colours are owing
sometimes to pigments in the scales and sometimes proceed
from the refraction of the light from the striations and
spots on the scales, from their formation and arrangement,
or from fine hairs which are found amoncrst them.

I 6

Gen M'e/uontuf IG*" '>fe/ir>n:a

Sb ntrclahnu!. I ''|> '^ordali ,

Fig. 13.

The scales are of great variety in shape and size,
arrangement and quantity, but arc generally very numerous,
in some cases more than 100,000 being found in one square
inch of wing-surface It is not surprising therefore that the
combination of such minute detail with every colour,

WING SCALES OF LEPIDOPTERA.

215

hue and shade, should produce the extreme diversity in
markings and patterns which are found in the Lepidoptera,
the less so when it is seen, as revealed by the microscope,
that the separate scales are often of more than one
colour.

It is through the means afforded them by the diversity
and variety of scales that some butterflies have assumed
a superficial resemblance to one another.

Fig. 13 illustrates two of the inedible South American
butterflies, one of the Heliconince, Hcliconins pardaliniis, and
one of the DanaiucF, MelincEa pardalis. Beneath them

Csa nO/ttWuA Gen iMiAUrwv*,
Fig-. 14.

V 15

Gen fitAX/r-Ui.

I . I and I . 6 are shewn respectively, magnified portions
of the wings of these insects, and it will be seen how very
different in pattern, size, shape and arrangement the
wing-scales are, whilst the butterflies are closely alike in

2l6 WING SCALES OF LEPIDOPTERA.

everyway. These butterflies are illustrated in Plate III.,
figs. I and 6.

In fig. 14 are shewn three butterflies from India,
Paralitica agica, Oriiioma daman's and Hcstiua uaiiia,
belonging to the sub-families Danaiiuc, Satyriiue and
Nymplialifue respectively. These insects are in no way
related, although found together or in the same localities,
and of very, much the same appearance in every way. (See
also illustrations in Plate V.) But the wing scales are
quite different in all three cases, as are also those of two
other butterflies, a /V/vvV/ and a J\ipilio, which simulate
them in the same region.

Fig. 15 illustrates two butterflies of remarkably similar
appearance, a Danaid, Cadiiga tytia, and one of the
Papilionincc, Cadugoidcs ao^cstor. They are both light grey
and pearly, with black lines on the fore wings, and deep
chocolate markings on the hind wings. But the resem-
blance is produced in quite a different manner ; in one the
scales are thinly dispersed, light chocolate, and shaped
like long thin skittles ; in the other they are thickly placed,
even overlapping, rounded and pure white, with a sprinkling
of dead black scales amongst them. The effect is, however,
an exact similar appearance in every detail, of colour,
and markings.

The conclusion to be drawn from these differences in
detail producing such striking resemblances is, that the
attribution of simulation to natural selection is the correct
one. Variations are constantly occurring in all directions,
and the scale-varieties which result in the remarkable
outward likenesses with [irotectivc results to the insects
which possess them, can be the result of no other process.
" For it seems manifest that these striking resemblances
" which are arrived at by such widely divergent means, can
" be reasonably explained on no other hypothesis than
" natural selection. . . . Under the weaning influence

VARIATIONS IN BUTTERFLY SCALES.

-1/

Sulr.fam J:>anaincs.
Gen . OadufcL

Sub fam. 7h.?>iZianincE,
Gc'n- . Cadut^ozdes-
^ 0.§.eslor

Fis-

"of elimination and selection of variations we should
" expect to find those essentially different methods of
"arriving at a common end which are here found to exist,
" and in natural selection only is a reasonable basis found
" for the various and devious means by which these
" remarkable simulations and picture likenesses are reached
" by so many separated species in nearly all geographical
" areas."*

* "Evolution in Butterfly Scales," by M. L. Sykes (Hioc. Manch. Micro. Socy , igoi.)

2l8

PROTKCTIVE RESEMBLANCE.

VI. Protective Resemblance.

Of the many means of protection found amongst insects
none are perhaps more interesting, or of greater diversity,
than those by which concealment is effected by similarity
of the insects to their surroundings. In every order,
from the Coleoptera to the Diptera, and in all stages of
metamorphosis, there are found almost endless examples of
this kind of protection. Leaves, twigs and flowers ; grass,
moss and lichen, root and bark, soils and stones, in every
field and hedgerow, are copied in great variety by insects
which live and shelter upon them.

Fig. i6. Ancylpcha luniiligeya (Borneo.

This form of simulation is of two kinds, or rather serves
two purposes ; firstly to render the animal less conspicuous
and hide it from its enemies ; and secondly to enable it to
capture its own prey by waiting in concealment, or by its
being mistaken for something else.

CHARAGIA DAPIINANDR.-E.

219

Caterpillars brown and green, plain and spotted,
banded and striped, lie concealed everywhere, or project
stiff, brown and bent from the branches and stems, exactly
like the twigs upon which they rest rigid and motionless.
They are to be found almost everywhere during the
summer months, but so closely do they resemble their
surroundings that they are very seldom seen, at least by
the human eye, and are often most difficult to detect even
when specially sought for.

'y

Figf. 17. Cliaragia daphnandrae (Queensland), with the wings expanded,
and at rest on bark. The fore wings are green, and the hind wings a rosy
red, The insect is eftectually concealed when at rest upon green bark as
illustrated.

The butterflies and moths which are protected in this
manner are very numerous ; amongst the beetles also are
a great many species which owe their safety to this
means.

The OrtJioptera are amongst the largest contributors to
this class of simulism : ' leaf-insects,' ' walking-sticks,' and

220

PIIASMID/E, OR 'stick' INSliCTS.

simulators of mosses, fungi and lichens, being very
numerous in this order.

Fig. 1 8 illustrates some of the PJiasmida from Ceylon,
Java, and Queensland, brown, dried-up looking animals,
much more like sticks than living creatures, and with them
are four small twigs upon which four of the insects are placed.

Fig-. 18. A gfroiip of " Stick " insects from Queensland, Borneo, Ceylon, &e.

A number of the simulating Orthoptera are shewn in
the next illustration. Fig 19. They include several species
of MantidcE ; Mantis religiosa, M. viridis, and others ;
some of the Triixilidtc from Africa, with both open and
closed wings, a young PJiylliuui siccifoliiun with brown
crumpled wings like dead and dried leaves, and two of the
large green coloured Trepidodera from Queensland. One
of these insects, T. Childreni, that on the right, shews the
transparent gauze-like hind wings partly exposed ; the
other is in the position of rest, with the wings closed and

SIMULATING (JRTHOPTERA.

221

Fig-, ig. A group ot " Stick " and " Leaf " iiTsccts from Australia, the
Malay.an islands, &:c.

folded over the back, and having the exact appearance of a
young plant with two bright green leaves and a pink based
green stern.

Fig. 20 illustrates a few more of these remarkable
leaf-like insects, most of them being from Africa. The
six specimens with the wings expanded have a beautiful
leaf-like appearance when the wings are closed, and the
insects are in repose. The fore wings are either green or
brown, the nervures are exactly like the veins of leaves
in both colour and pattern ; and the concealment amongst
vegetation is complete when the gauzy hind wings are
folded away and the insects are resting. In one of these,
Arantia, the wings are studded all over with yellow spots,
in precisely the same way as a fungus-spotted leaf is often
found. In the centre of the same illustration is a very

222

LEAF' AND 'STICK' INSECTS.

Stick-like Phasmid, londwdes from Queensland, and above
are two of the ]\Iantidce, green and brown respectively, in
the attitude of quiescence.

All the MantidcE are carnivorous, feeding upon insects
of other kinds, and sometimes upon their own species ; and
their method of securing their food is the same. Crouching
upon some plant, or upon the ground, the Mantis raises

Fig. 20. .\ group of " Leaf" and " Stick " insects from.'Queensland, Africa, &c.

the fore part of the body, folds the long fore limbs together,
and remains motionless, some times for hours, but always
ready to grasp any unwary insect which may approach
close enough to be secured. All the different species are
coloured to harmonise with their surroundings, and their
wings have the appearance of green or faded and crumpled
leaves. The protective resemblance serves here a two-fold
purpose ; to hide the insect from other animals which feed
upon the Alantidcs, and to conceal it from the insects upon

MANTIS RELIGIOSA SEIZING PREY. 223

which it feeds ; the brown, or green, or rosy colouring,
venation of the wings, and the twig-Hke appearance of the
legs effectually concealing the animal during repose.
Fig. 21 shews the Mantis rcligiosa in the act of seizing a fly.

Fig. 21. Mantis i-eligiosa, in the atLitude oi sc-izing prey.

The Mantis shewn in the next illustration, a species of
Phyllocraiiia from Ceylon, is even more leaflike than the
last named insect (Fig. 22). The wings are varied, green
and brown, and are folded over the abdomen in exact
imitation of a rolled up leaf, whilst the expansions on the
thorax and the legs add still further to the simulation of
the foliage amongst which the insect rests.

Pliyliiinu siccifoliuni is another excellent example of
protective resemblance. The fore wings are of large area,
completely covering the body of the insect when at rest ;
they are somewhat rounded, and strongly veined and
marked with numerous lines. The young insect is of a

224

'leaf' insect from CEYLON.

Fig. 22. Phyllocrania sp. (Ceylon.)

yellowish brown colour, and has a decided resemblance to
a brown and withered leaf; but as it grows older its colour
gradually changes from brown to a bright green, and the
perfect insect, the matura, acquires a wonderful resemblance
to some of the vivid and shining green leaves of tropical
forests (Fig. 23).

Amongst the many curious and interesting insects
which are found in Ceylon, Empiisa gongylodcs, is one of
the most singular. It is a brown insect. The thorax is
like a long thin twig, with a wide leaflike expansion
immediately behind the head. The wings are broad,
veined and crumpled, like dried leaves ; and the long legs,
which are spread out in any direction as the animal is at
rest, harmonise so closely with the twigs to which they
cling, that it is difficult to see where one begins and the
other ends. Fig. 24 illustrates this insect in the attitude in
which it was resting before being captured.

LKAF INSECTS.

!25

Fig-. 23. Phylliiiiii siciifoliiiin (Fiji.)

Fiff. 24. Einpiisa go)tgylodcs (Cc\ Ion,) i\i rest on tw i

226

A CEYLON ESE SIMULATION.

Another interesting insect from Ceylon is one of the
moths, Eurybrachis Westivoodii. The fore wings of this
insect are marked in a mottled pattern of green, grey
and brown ; the hind wings being white, with deep claret-
coloured marks near their base ; and when it is on the
wing the moth is an attractive looking creature. But its
appearance alters when it is at rest, with the mottled wings
folded over the back. In Fig. 25 it is shewn with the
wings expanded as it appears when flying, and below is a
piece of bark with the same insect resting upon it, and

■ ^'^^f^

L.'^k

St.sitS'jM

^v h

,jp*

^^BlB^5vi^R2l

gSQ^-v

0^^'

^^. ^^

'^.^

Ij

t^Jx^m

^^^VkMtflHv

tt^'^l

Kti 14- ^^M

wiUvS^

m

mS^M-'^t

Kf

i

1 i^ * vJe

1/

M

1} i,^i3i

M

■

,<

\

i

1

^NiS

1

Fig. 25. Eiiryhrachis IVestwoodii (Ceylon,) with tlio wings
expanded, .ind at rest upon a piece of bark.

where it was discovered by the keen sight of the collector ;
a clever capture, as will be admitted, when it is noticed

A MADAGASCAR BEETLE.

227

how excellently the colours harmonize, and how the insect
and the bark seem almost to merge one into the other.*

There is found in Madagascar a small beetle, which,
looked at apart from its natural surroundings, has nothing
specially interesting about it, except that it is a conspicuous,
rugged looking, pure white and black insect, about three-
quarters of an inch long. It feeds upon a species of
fungus, which grows upon the bark of trees in mixed
cream and black coloured patches. The beetle is shewn at
the top of Fig. 26, and beneath it a piece of twig with the

Fig. 26. Liihinus ntgi-ocristatus (Madagascar.) The upper
figures shew beetle and bark separately, and in the lower figure
the beetle is on the bark.

fungus growing upon it. At the bottom of the same
illustration the same piece of fungus-covered twig is shewn,

* I am greatly indebted to my friend Colonel W. G. Clements for many beautiful and
remarkable specimens of Protective Resemblance, including those illustrated in Figs. 22
to 26.

228

'leaf' insects from BORNEO.

but here the beetle is resting right in the middle of the
fungus, effectually concealed amongst the vegetation upon
which it feeds. There is a very fine group of these beetles
shewn in one of the 'Mimicry' cases in the Natural History
Museum at South Kensington.

The leaflike Orthopteron, shewn in Fig. i6, illustrated
on page 218, is from Borneo, which, like other Malayan
and Australasian islands, has afforded a wealth of interesting
material for the entomologist. The fore wings are green,
with leaf-like veins and nervures, and there are two spots
upon them which are exactly like the fungus spots so
often found upon leaves, whilst the stiff-set legs have the
appearance of thorn-clothed brown twigs. Another very
similar insect, also from Borneo, is shewn in the next
illustration (Fig. 27,) the leaflike green wing having a
small round transparent patch, like a hole in a leaf.

Fig. 27. ('/riiiit/riis jirrii/oliiis (Borneo.)

Of the many butterflies and moths which have the

PAL.liOTROriCAL ' LFAF ' INSECTS.

229

appearance of leaves when the insects are at rest, none are
more perfect than the various species of Kalliiiuv, found in
the pahtotropical regions. Reference has ah-eady been made
to these butterflies on page 189, and in Fig. 28 the
upper surfaces are shewn of several species, including
Kalliuia paralckta, K. iiiacliis^ K. albofasciata, K. philarchiis,
K. Buxtoni and A', niinia, together with several DolescJiallia;
and Anacc, and in the upper centre a pair of Zcnxidia
amcthysta. All these insects are highly coloured, generally

Fig. 28. ■• Leaf butterflies " : shewing upper (briglitly coloured) surfaces
ot wings. (See Fig. 29.)

in various .shades of bright blue, some varied with black,
some with orange or white bands across the fore wings,
some .shot with heliotrope or purple ; all are handsome
butterflies, conspicuously coloured on the upper surfaces
of the wings.

230 UNDER SURFACES OF 'LEAF' BUTTERFLIES.

The next illustration (Fig. 29) shews exactly the same
butterflies, but arranged, unfortunately, in somewhat
different order. In this case the undersides only of the
insects are shewn, the wings being in every case shaped
and marked like leaves in various stages of decay, many

Fig. 29. " Lent butterflies" : shewing under (leaf like) surfaces
of wings. (See Fig. 28.)

with blotches and patches of brown or yellow, like the
mildew and fungus found on dead or decaying vegetation,
and some with small transparent spots upon them, which
give the appearance of small holes in dead leaves. These
butterflies always rest with the wings folded over the
back, the undersides only being exposed, and as they
habitually settle amongst the decaying vegetation of the
tropical forest the simulation to their environment possesses

A 'LEAF' INSECT AT REST. 23 1

a measure of almost extreme protective value. One of
these insects, K. paralckta, is seen in the attitude of repose
in Fig. 30.

Fig. 30. KalUina payalehta, at rest on twig'.

Most of the subjects illustrated and described above
are selected from amongst the tropical fauna, as being
comparatively little known ; but the British insecta include
amongst their numbers, in all stages, larvae, pupae
and matura;, many varied and beautiful examples of
the interesting and attractive subject of Protective
Resemblance.

(Three additional plates are inserted here in further
illustration of the resemblances between edible and inedible
butterflies, viz., Plates VII., VIII., and IX. ; also a plate
giving additional illustrations of differences in the shape,
size, and arrangement of the scales of some butterflies having
superficial resemblances to each other, viz., Plate X.)

23:

INSTANCES OF SIMULISM.

'^ ,.; « '^
2 -S -^i CO

<s 5 'a <i: ai =?

•?^^

c^^Q

<1 2

^ (^ OJ iZ

o

o

Q^-^i^;'

1^
^ 2 a;

•?^-^ S

g.y^ ^

1-^

'^G^

C/}fe

•i: <^

>

■^

« 5.y ii

g g -^ _u ■" ^

w

5 s <i li: d c^

H

<;

H-)

Ch

fe

^

M

C

^

^

^

.a:

H

5;

.^•S . C a3

U

CD

Daiiai
A mail.
Niavh
Africa.
GaVjoo
Femal

Nymp

Sp._
Africa,
Gaboo
Femal

W

Q

.s ^.« ^.y cu

^■s .2

s s k s^S^-'rt

Nymp

Eiiral

Sp.

S. Afr

Natal.

Male.

s 2 .,$■?<; 5 1

*3 ^ ^0 -^ cti oj

c:) ^ i*^ ^ c/: ^ P^

Qrjjo

U

:«

irf

2 ^ .« .0 ctj
^^ ^< "'ii

i_j 1)

2 ^

g a B u --i _o
« 5 -2 LS C t*

■C*."^ 5; ci ai ■

<; fccj "^ < c/} I

S? ^^cJ

•^
f^^^

Tj- c

2'3

1|; dfe.- 2 3

3 <

fit '7) O Cfi K 1-5 C/}

• < ^ >^

;:; D w d: <

2i W

o

h-JcAi fe c« c/: > E hJ c/: Ph O! O Ol K iJ C/3

INSTANCES OF SIMULISM.

233

—

m "5 "

00

^i ^ ^

--:

=« fe'

" ^." « £<

•S "■<

•Si ts-

rt

s

1 ":9.

5 ^ ::^ •

'c'

a.

6
13

^S 1.5 S-^

Papilion
Papilio.
C annus
Oriental
Borneo.
Male.

5 1~ ^"^ -« 3

is

'Si

C-o

rt "

• ^ '-I 5: cs

~S -S 5 rt :- oJ

;o:

^ w «

<;

Euplceiii

/^anisep,

h'hadaiii

India.

Assam.

Male.

Nynipha

Hestina.

Ida.

India.

Assam.

Female.

•252

~S t.; '^ -^

•? '^5

_ij

-5 $ _~ ^ i,

>^-S-2 ,^

13

■^■^^ ci-i'^

g

H

U

Danaincv.

Tirnmala,

.Sepicntrioiii

India, Assai

Cherrapunji

Male.

Elymniinic.

Elyiiinias.

'Pima7idra

Assam.

Cherrapunji

Female.

i

15

"1 l-s 1

w

-5 S c3-2 "=3

i-"? 1 1

,-

Q

^^--1

13

,~ k <i >;
k^ ^ ^0 ►:5 m t,

^■^■^:^

y^.

p <u

^

so

c3
'5

^

Danaiiuc.
Tirnmala.
Limniace
Assam, Ind
Ceylon.

Paptlionuia
Paranticops
X en odes (

d
•S

c

s

9

Euphvin(C.

Crastia.

Core (Cra:

India.

Bombay.

Female.

^ ; hJ

-5 ^ ^ rt -g rt
.c Q :; IP p P
5^;^ .•: ^ O 5

s

<

rh CQ 5i

^ D W

h 2

0; < q

C/3 3- I— I

< . . , .

u K Z « u X

H D w c: < o w

Ph c/: O cc !I^ J cA!

;<^

H ' i 5 >^

tti CO O c/: iJH i-J 'A!

<

< o

" ^ "T O. _ >-< K

fe /". O fy: U (/:■

234

INSTANCE.S OF SIMULLSM.

CS

OJ

■^ ^ ^ ■< C/2fe

?0

E .

%J

S .^.§

^ 5.U

~ J: « >i:

oj

•~ <3 ^ i£

g^S-^

g

^ ^|<

^;

Sr ^. <a rt

Sj vo ^^

u

^ ^ »>*

Ely in lit i,
Elyinnia
Banimak
W. Afric

■^^'^w

fe

"^^^W

t^

fe

9m

0)

l^ ^ . ^

.s 5

ema.

(Fabi
a.

a Leoi
lie.

> s- ^ --^

S o V. ;;

^ 5: -N. N

^ SS § g

-b<> 1 .•

■^ "^S <la3ti<

ttjkqcc;;^

•5 « taiS
^ «j k <ti u

•^^i^W 2

^ ^ *o u :« <!)

1

:;

*l

1

1

:4'«

W

>-< ~ (3 ;•» C

|. J I >• .H S

<; '^ =Q > c/: ^

.• ►; t*

t 2 g

lS.5 £
<! c/5 tt<

iliou

ilio.

orta

Afric

ra Li

e.

US

■? ? H * =« •

^ ^ .S .o •- _aj

b b SqIH i3 3

^'^'t^-<c;5S

.:- s rt .-,

■§ I it 6

lO -—

^ "i.

^"3 J3 ,^

Ci,^"

o^ ;5 g

?^ s s^

tenia,
yta (
Africa,
ra Leo
e.

Papilioniii.
rapilio.
Latreillian
W. Africa.
Sierra Leo
Female (u;

(i Z

< -

. S 5 ><

S :
•a: •
(^ .

ii D w d:

5£

55x

it- .

- 3

2 5^-

(iic/^OcDSi-J'y) Uhc/;Oc/3H)Jc/3 ticc/:Oc/:U7:

WiW

^

II ■)

Swif/om. <Sillui.\n«

Ge-n Lytovsa

'^ A

Sulfoin. PitTimt- .

Ge-n. J)ismoT^bht«-
5); fVa..ino4

IV /

Gen My^holimvas

SJ3 r/ahliergU

\^l^

IV S IV I

<Jen. ^/)ohmifai jGe". Amawtt

1

Murk L. .Sv/,T.s, del ad nat.

J •lair .v.

Tlie illustralions on I'late X and on pages 214,
215 and 217, (if magnified scales on the wings of
Butterflies, are from camera lucida dra\\ings of portions
of the discoidal cells in the hind wings of the Butterflies
shewn in the same illustrations.

See page 214 et Seq.

Simulating Danain.e, from Vene/.uel.-i.
Melincea lilt's. Mechanitis veritahilis {,

Mechanltis veritahilis ? Tithorca Doublcdayi.

Ceratinia dionica.

:!S'?;as!;.!;fii!!ii!;:"^;?53iai;|;i

'ii-ii

li«!lJiaiSi:iHli2iiii5liMaESlt3.iiiHila!;iS

SMITHSONIAN INSTITUTION LIBRARIES

i 3 9088 00735 3824

iM>IR}lft)t»ltttmHiiP^ lUinU lU I )4;wnH;i 3HR K-lUnUthft Mt:iftHHU! |h 111 ti ,H jUiHi^

tbJu^^a-^L <>t4tk'J(inuiUlttt»IRj»tv>;)».*i»;j:[l(mtl3W

J r.i^miHt(it^itin>iiiiili;ii.:usi^