DETERMINATE EVOLUTION IN THE COLOR-
PATTERN OF THE LADY-BEETLES
BY
ROSWELL H. JOHNSON
WASHINGTON, D. C.
PUBLISHED BY THE CARNEGIE INSTITUTION OF WASHINGTON
1910
CARNEGIE INSTITUTION OF WASHINGTON
PUBLICATION No. 122
PAPERS OF THE STATION FOR EXPERIMENTAL EVOLUTION No. 15
Copies of this Book
were first iss
JUN291910
THE CORN M \N I'ltl NTI N<; COMPANY,
( \ i: i isi. I-:. i'i:\ \>i i.\ \ \ I A.
CONTENTS.
Page
PART 1- INTRODUCTORY CONSIDERATIONS
Principles of classification 4
Structure of pigmented areas 6
Development of pigmented areas
Utility of the color-pattern 9
Life and habits 10
Variation and heredity of body-length 13
Acknowledgments 14
PART II.— THE DATA ARRANGED BY SPECIES 15
Hippodamini 15
Anisosticta 15
strigata 15
Naemia 15
seriata 15
Nacronaemia 16
episcopalis 16
Paranaemia 16
vittigera 16
Megilla 16
maculata 16
Ceratomegilla 17
ulkei 17
Eriopsis 17
connexa 17
Hippodamia 1"
glacialis 19
convergens 21
bowditchi 45
spuria 46
oregonensis 48
cockerelli 49
dispar 50
sinuata 50
tredecimpunctata 50
americana 52
parenthesis 52
apicalis 54
lengi 54
falcigera 55
Coccinellini 56
Neoharmonia 56
venusta 56
notulata 56
ampla 56
iii
iv CONTENTS.
PART II. — THE DATA ARRANGED BY SPECIES— Continued.
Coccinellini— Continued. Paue
Coccinella 57
perplexa 57
tricuspis 59
novemnotata 5'.»
johnsoni 61
transversoguttata 61
calif ornica 62
monticola 63
difficilis 64
suturallis 64
prolongata' 64
Cycloneda 65
sanguinea 65
munda 65
ater 65
Olla 66
abdominalis 66
pi agi a ta 66
Adalia 67
bipunctata 67
frigida 68
annectans 70
Cleis 72
picta 72
hudsonica 72
Agrabia 73
cy anoptera 73
Anisocalvia 73
duodecimmaculata 73
quatuordecimguttata 73
Anatis 74
quindecimpunctata 74
mali 74
rathvoni 74
lecon tei 74
Epilachnini 75
Epilachina 75
borealis 75
toweri 78
corrupta 79
mexicana 79
PART III. —GENERAL DISCUSSION 81
Variation 81
Modification 84
Distribution 86
Heredity 91
Phylogeny 94
Evolution 95
Summary of conclusions 102
Bibliography 103
DETERMINATE EVOLUTION IN THE COLOR-
PATTERN OF THE LADY-BEETLES
BY
ROSWELL H. JOHNSON
PART I.
INTRODUCTORY CONSIDERATIONS.
The lady-beetles were considered desirable for this study because their
variability, distribution, and taxonomy indicated that they had been
recently and are probably now in an active state of evolution. The prac-
tical advantage that they could be obtained in considerable numbers from
many localities and could be experimentally bred was, then, decisive in
their favor.
All of the American coccinellids which could be obtained in numbers
and which showed a variable color-pattern were studied, viz, Hippodamini,
Coccinellce, and Epilachnini, divisions employed by Casey (1899).
The Epilachnini differ from the rest of the family in being leaf-eating,
in having longer generations, and in hibernating necessarily in the winter;
whereas the other coccinellids which eat aphids, fungus spores, and pollen
will remain active during the winter in a vivarium and give many more
generations. The difficulties of keeping a large and constant stock of
aphids on hand and keeping the beetles free from diseases, especially such
as result from dampness in the late summer and irregular temperatures
in the winter, proved to be very serious and prematurely shortened many
pedigrees. These difficulties also decreased the numbers which could be
successfully managed. Nearly all the pedigrees, however, are given,
for when too fragmentary to have much value in the study of dominance
and segregation, they are, nevertheless, of value in showing the transmissi-
bility of some characters and variation from the parent.
The dorsal color-pattern in all the American species within these groups
is given for the sake of completeness, although for some species but
little variation data was obtainable. This fact, together with the necessity
of carrying in mind the data of variation and distribution in discussing
experiments upon any given species, has led me to arrange the presenta-
tion according to species, after this introductory section. Furthermore,
this arrangement will be more advantageous for those whose interest in
this contribution is primarily taxonomic.
Every considerable new accession of data involves another revision of
these tribes, since there has been so much disagreement among the authors
and since the lines between varieties and species in these remarkable genera
are so doubtful. I am obliged, therefore, to present a revision of my own
in order to have a suitable nomenclature. Since the revision is not an
end in itself, I have not given full descriptions, but only discussed and
illustrated the color-pattern of the parts studied, although of course the
revision is based upon many characteristics.
Not having studied the structural features of the foreign species, I have
not ventured to revise the genera and have simply adopted the genera
as used by Casey.
EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES.
The differences in sculpture of the elytra have not been found to have
the constancy and systematic value which some of the earlier writers
have placed upon them. The variation is, moreover, largely ontogenetic,
as I have observed in the pedigreed material. The shape of the elytra
must also be used with considerable caution, because of its variability, as
shown in table 2, and the optical illusions from the angle at which they
harden and from the longitudinality or the reverse of the pattern.
The sex of the individuals has in most cases been observed; always in
the experiments. The same sex is not the more heavily pigmented in
every species. The sexes are not given separately except where the
difference was obviously significant. The color-patterns of the larvae have
been used in evaluating relationships in some cases, but their description
is outside the field of this paper.
The numbering of the elytral spots employed in Hippodamia coiiveru<'iix
follows Weise, not Kellogg and Bell (see figs. 3, b, and 17) . In other genera
a corresponding system is employed: + is used to indicate confluence, apto
indicate a close approach to confluence, s/+ for a very slight confluence,
and tr for transition between separateness and confluence.
Formulae are used where possible to designate unnamed varieties; in
other cases it has been necessary to use letters. New names have been
given to varieties only when they are common, distinct, and frequently
collected, so that a name is needed.
PRINCIPLES OF CLASSIFICATION.
There is an improper demand for finality of treatment on the part of
many systematists. These workers wish to use a treatise almost solely for
the purpose of definitely dividing their collected specimens into categories.
Such a demand leads many systematic writers to a false positiveness in
regard to distinctions and evaluations. Many revisions are thus led to
present a precision and show of finality which is not justified. New names
involving new distinctions are valuable, but the reviser who fails to bring
to light the points of doubt and uncertainty as well is negligent. A revi-
sion should give questions as well as answers; it should not only shed
light, but indicate where more light is needed. To assume surety on an
inadequate basis is inimical to the advance of science. On the other hand,
there are some who go to the other extreme and hesitate about calling
attention to an apparently new species, or some other difference, until they
feel wholly assured. This policy retards progress and may result in the
information never being made public because of the intervening death,
incapacity, or disinclination of the investigator. An impression based
upon extensive special knowledge has scientific value, provided it is avow-
edly only an impression. I have not sought, therefore, in this revision any
degree of finality, but have tried to adopt a nomenclature which, from
PRINCIPLES OF CLASSIFICATION. 5
present data, seems the nearest approximation I can make to the true
condition, for I well know that its usefulness will soon be past.
I believe that it is very important that the International Congress of
Zoologists should adopt a set of definitions of species and the less inclusive
taxonomic grades in order that some uniformity can be attained in the
use of such words as varieties, subspecies, forms, aberrations, mutations,
etc. Until that time each writer must define his use of such terms when-
ever called upon to use them extensively. Failure to do this is causing a
constantly growing confusion.
The following definitions will show the meaning of the terms as here
employed. I am well aware that many of these terms are used differently
by some writers, but at present each worker can merely choose the use
that seems most satisfactory to him.
A species consists of individuals which, aside from sex, age, and periodic
differences, have a fundamental similarity and which are habitually and
successfully interbreeding. They comprise an intergenerating unit.
A section is a part of a species which is cut off by some barrier from
intergeneration. Where the individuals of the section have no apparent
difference from the mass of the species the section is ignored. Where
the difference is so great that individuals of the two sections are always
readily distinguished, a distinctive name becomes desirable and the form
is considered another species rather than a section, although experiment-
ally the two will interbreed freely. The difference between section and
species is one only of degree of difference in the characteristics. The sec-
tion may be found to be ontogenetic or phylogenetic in its nature.
A subspecies is a part of a species which inhabits only a portion of the
range of the species and which, while differing in some appreciable respect,
intergrades with it in the intermediate region. At any one point through-
out the range of the species the quantitative expression of the chief differ-
ential of a number of individuals similar in age, sex, and season should
give a unimodal polygon of frequency. The term "subspecies" maybe
used without reference to the inheritability of the differences. But where
these differences are found primarily because they are the result of
environment in each generation, the subspecies is called an ontogenetic
subspecies. Where it is present primarily because inherited it is called a
phylogenetic subspecies.
If the conditions of a subspecies are fulfilled, except that the individuals
in question are scattered geographically and are confined to a particular
kind of habitat throughout its range, then we have a habitat-form,
which may be ontogenetic or phylogenetic. The usual assumption that all
habitat-forms are ontogenetic is, I think, questionable, although they are
probably generally so. The distinction between a subspecies and a habitat-
form is not a sharp one, for a subspecies is a habitat-form where the
habitat involves a very large, continuous area. The habitat-form falls
6 EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES.
short of a subspecies when the habitat is made up of many discontinuous
areas surrounded by a population of the contrasted forms.
A variety is a part of the species which differs from the typical members
of the species by some hiatus which can be detected by the decreased
number or absence of intergrades. When some considerable imperfection
of the interfertility of the apparent variety and the typical species is found
or some other cause makes their interbreeding- uncommon, the variety
becomes a species. Only an arbitrary line can be drawn, and to make an
arbitrarily definite one would be infeasible at the present stage of our
science. The variety may be equally common throughout the range of
the species; it may be much more common in one part; it may be limited
to one part of the range; or it may wholly replace the species in one part
of the range. If its frequency only gradually changes in one direction, a
subspecies is there constituted. If the variety is confined to a particular
habitat, we have a habitat-variety.
An aberration is an individual which is wholly unique, generally patho-
logical in origin, and often unsymmetrical. Where the character is sym-
metrical and there are no pathological appearances or the variation is of a
sort found normally in other species, the specimen is probably one of a
rare variety rather than an aberration.
A mutation is a specimen of a variety which is known to be capable of
hereditary transmission, but the ancestors of which are typical individuals
of the species. Where this information is lacking the apparent mutation
can only be considered to be a rare variety, the origin of which is probably
traceable to a progenitor more or less remote.
An extreme fluctuant is an individual which appears sufficiently dif-
ferent to be noticeable, but is, nevertheless, only an extreme case of the
ordinary fluctuation, as is shown by the greater frequency of the inter-
mediate conditions.
Form is a term of convenience only, applied to differences the real
nature of which is in question. Many forms will later be found to be
extreme fluctuants, others may represent points in a fluctuating series
easily recognized or described, while still others are doubtless real posi-
tions of organic stability, which further study will show to be varieties or
intermediate conditions between varieties and continuous variations.
STRUCTURE OF PIGMENTED AREAS.
I have limited the work, with a few exceptions, to the color-pattern, be-
cause with the other characters we have for the most part stable conditions
with only a little fluctuating variation. For the further advantages of
specialization I have concentrated my attention upon the pronotum and
elytron. I believe, however, that similar results would have resulted were
the study extended to include the coloration of the larva and the remaining
parts of the imago. The coloration of the pupa, however, is rquch more
subject to modification.
STRUCTURE OF PIGMENTED AREAS.
That the attachments of the muscles have an influence on the color-
pattern of the head and pronotum is probable. I have not felt it neces-
sary to go into the matter of structure of these parts in detail, however,
because the great range of variation in the color-pattern within a genus,
or even within a species, where the structure cowld not differ in any but
a slight degree, is such that the influence of structure can be only along
narrow lines.
In the elytra the influence of structure is more evident, but less than
might be expected. The sutural margin is thickened and paralleled by a
slight groove. As will be seen later, this margin is especially subject to pig-
mentation, and this in fact distinguishes several species and varieties.
Spots are confluent with it in a few species and may become so by modifi-
cation by cold in Hippodamia cowwrfieus. Yet, in general, when spots
near the suture enlarge, their margins, which if they remained circular
would become tangent to the suture, flatten and become parallel to the
suture without touching it.
Fie. 1.— Position of linea interim, liix-a nif
, f'nci'iiiellit: c, ffiiipotlainia: il, Anulix; e, h'/ii/ac/inn.
The lateral and basal margin is much modified structurally in variations
of germinal origin. It is one of the parts least subject to pigmentation.
In modification by cold, however, pigment readily extends along it from
neighboring spots.
In Adah' a three veins are visible, named by Schroeder (1901) linea
interna, linea media, and linea externa (fig. 1). The linea externa is
quite close to the reflexed margin. It departs farthest at the humeral
angle, where it can be most clearly seen. Any other veins that exist
must be in the modified and thickened sutural or marginal parts of the
elytra. The influence of these lines on the color-pattern of Adalia is
considerable, as shown by Schroeder (1901).
But in Coccinella the linea externa can not be seen in the hardened ely-
tron; yet its path can be traced in the basal half of the elytra by the
extension of pigment along its course in C. iwvemnotata from the spots 1
and 2 along the linea externa. This is farther from the margin than in
Adalia. It is probable that there is a vein in the soft elytron, visible evi-
dence of which (to the hand-lens) does not persist in the mature wing.
In Hippodamia also the linea externa is not visible. Its course is outT
lined by pigment in cases of modification by cold and in the two wild
EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES.
specimens shown in figs. 25, 16, aa, and 16, 66. In Epilachna and Anatis
it is not visible and no cases were seen of pigment disturbance.
Pigment follows along the veins readily, especially along the linea ex-
terna, in cases of increase of pigment by modification; but in varieties of
spotted species of germinal constitution the influence of veins is not great.
The vittas wrhen present are frequently at an angle to the course of the
veins or broader upon one side of it than the other. Transverse confluence,
which is not influenced by any elytral structures, is more common than
vittae.
There is pressure upon the elytron from below at the humeral spot by
the basal attachment of the wing below, at the site of spot e by a projec-
tion of the thoracic plates, at and near the site of spots 4 and 5 by the fold-
ing of the wings beneath, and at spot 6 by the tip of the abdomen when
bent back, as it frequently is. Nevertheless these spots are not infre-
quently absent and there is no especial pressure where other spots are
present. From these considerations and the well-known theoretical
objections to kinetogenetic origins of germinal characteristics, I am not
disposed to see any causal relation between pressure from below and the
position of the spots, although the coincidence is striking in the second
case.
DEVELOPMENT OF PIGMENTED AREAS.
The color-pattern of the head and thorax are fully formed at time of
emergence. The black pattern of the elytra is formed subsequently. The
soft, freshly expanded elytra are free from all black pigment. This is true
in all the species which I saw emerge, including Epilachna borealis, of
which the contrary has been stated.
No sequence in the appearance of spots could be positively determined,
so nearly simultaneous is their development and so gradual is their appear-
ance. Where the pattern is composed of strongly confluent spots, the
pattern appeared at once, though not at first of full intensity, without pass-
ing through a separate spot stage. The pigment area, however, increased
slightly during the few successive days after emergence before the elytra
were fully hardened. This extension was so slight that it would not have
been detected but that the pattern of a few freshly-emerged beetles, the
pigment of which had become fully black, were described as having spots
1 and 3 very close together, but separate. Several days later they were
found to be slightly confluent. Confluence of this kind, however, is only
seen where the contiguous spots are unduly large and is the result of a
mere enlargement of spots. Their inheritance is like that of an extreme
fluctuant, as shown in pedigree table 15. Confluence, therefore, is of two
kinds. In confluence of the hereditary type, the spots may be quite small
and distant, as in Epilachna corrupta.
THE UTILITY OF THE COLOR-PATTERN. 9
THE UTILITY OF THE COLOR-PATTERN.
The utility of the color-pattern is obviously not that of protective resem-
blance, for it is decidedly conspicuous in the green surroundings which the
beetles frequent. This conspicuousness is generally thought to be expli-
cable as a result of the habit these beetles have when disturbed of expel-
ling a disagreeable fluid from the ends of the femora. The possession
of a striking and peculiar appearance, by which the bird or other pre-
daceous animal might associate this painful experience, would obviously
be advantageous. In Poulton's terminology the color is aposematic. The
only other explanation that seems at all plausible is that of sexual attrac-
tiveness, i. e., the color is epigamic. The apparent indifference with which
Hippodamia convergens, spotted or unspotted, breed together at Berkeley,
California, although both forms are common there, makes this unlikely.
I collected a number of mating pairs and could see no evidence for either
assortative or preferential mating, in this confirming Kellogg, who also
collected a number of mating pairs and reached the same conclusion.
The explanation of the ground-color of these beetles as warning or apo-
sematic may be accepted upon the following evidence from Judd (1899),
based upon extensive examinations of the stomachs of birds:
In the Coccinellidas we have showy insects, ill-scented or flavored, that are eaten by
but very few birds— the flycatchers and swallows ; and hence here is a whole family
which conforms well with the theory of warning coloration. * * * The showy, ill-
flavored Coccinellidae [are] * * * almost as * * * highly protected from birds
as the hairy caterpillars and the elm leaf-beetle.
To this may be added my attempt to feed Coccinella novemnotata to a
catbird reared in captivity. The bird took the beetle up to its perch, but
then dropped it. The beetle walked away without further molestation.
Since Judd finds that the barred and spotless species as well as the
spotted species are protected, the particular patterns can be of little im-
portance, although they are so diverse. In flight, where the beetles are
most attacked, the pattern is inconspicuous, while the ground-color is evi-
dent. But what is quite conclusive is the origin and persistence of varieties
having fundamental differences from the pattern of the spots of the par-
ent species. The fundamental usefulness of an aposematic pattern would
depend, above all, upon its constancy. If the spotted pattern, which is
so widespread in the family and is the primitive pattern for many genera
or subgenera, has a strong association value with distastefulness, all
departures from it would be suicidal; yet we find they are not. It is
certain, then, that there is no high selective value in the spotted pattern,
but it is possible that there is a feeble one. The loss of the spots or their
change into other patterns must, then, be the result of some stronger
evolutionary force, which I believe to be determinate evolution, over-
coming the slight advantage placed on spottedness by natural selection.
10 EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES.
This cause will be discussed after the presentation of the data. It is
referred to here that the reader may bear in mind the question of utility
cerans determinate evolution as the species and varieties are described.
LIFE AND HABITS.
It is not necessary to give any detailed account of the habits of these
insects for the purpose of this article. Only those features will be selected
that are significant for this discussion of the color-evolution. Lady-beetles
are probably well protected from predaceous animals by their distasteful-
ness, as shown by the experiment with the catbird. In the localities
where they are abundant I have never seen them attacked. Frequent
causes of death are parasitism by internal insect larva?, an unknown dis-
ease, and difficulty in casting the larval skins on emergence from the pupa ;
but the two great causes of death are hibernation and the maldistribution
of eggs. Any considerable advantage in either of these respects would be
strongly favored by natural selection.
Epilarl/tnt is uncommon in the spring at Cold Spring Harbor until the
new brood comes forth, when it is quite abundant. Efforts to hibernate
it under as favorable conditions as I could arrange succeeded in not
more than 50 per cent of the individuals. Attempted hibernation with
other species was unsuccessful, although some, when provided with food,
overlived the winter in the vivarium. The critical conditions seem to be
extremes of dryness and moisture. MeyiUo nmctiJtita hibernates, at least
frequently, in masses, one of which was found and kindly sent me by Dr.
Robert W. Hall, of Lehigh University. I am assured by Prof. N. F. Davis,
of Bucknell College, that in the spring such a mass was seen to mount a
fence-post preparatory to flight. In the Western States Hippodamia con-
vergent* and spuria.Yesort to the same practice. Strangely enough, such
masses were frequently found on mountain-tops throughout the Western
States. This is probably not adaptive, but a by-product of some tropisms.
These beetles are found in great numbers in the flotsam of the shore of
large bodies of water when a certain sequence of winds occurs during
the time when large numbers are in their long flight. The ability to collect
large numbers on mountain-tops and shores has been a favoring circum-
stance to the collection of material for this paper1. I would like here to
solicit the opportunity of examining any such masses, and I will gladly
return them if desired.
While these beetles fly very little in cloudy weather, on warm sunny days
they frequently take long flights. This is important as breaking down
the probability of isolation, widening the range of varieties, and making
their passage into species more difficult. Dispersal is probably even more
effective than in birds, which have such powerful homing instincts,
although of course the occasional storm-driven bird frequently gets much
farther astray.
LIFE AND HABITS. 11
The food of these beetles is well known to consist principally of aphids.
Certain coccids are eaten by some of the species, but this is the exception.
A coccid of the chestnut constitutes one of the principal foods of Cijcloneda
munda at Cold Spring- Harbor. This coccid is not eaten by any of the
other species. Meyilla fiiscilabris is also peculiar in its food habits, for it
eats a much larger proportion of pollen and fungus spores than are eaten
by the other species. In general, coccinellids eat a wide range of species
of aphids. Some species of aphids are found to be especially attacked by
some species of lady-beetles; thus, that of Rhanumx c'imiles.
FIG. 2.— Variation ol' length ol'rl.vtra of JIij>i>ml;i; Sand Hill;;. Nebraska. Thep-e specimens piobably
represent a subspecies, for a specimen showing nearly as much separation
came from Beaver Dam, Wisconsin. Specimens of the typical species of
the variety (lohrifinti are rare.
Var. B.
A specimen from Wyoming shows spots fused into two marks, except the juxta-
sutural spots, which are free.
Weise records 2 specimens of A. novemdecimpunctata var. irrcniilaris
with 1, 2, 3 -I i, 4 i 5, 6 the suture, 7 ! 8, 9 (his numbering), from
Oregon. This throws some doubt on the specific distinction between A.
novemdecimpunctata and stririata. The difference in the elytral markings
are certainly bridged over by our variations.
Genus NAEMIA Mulsant.
3034. Nacmia seriata Mulsant.
Distribution: Maritime regions of the eastern United States and south-
ern California.
Form n. The spots separate, but the apical spot meets the suture.
Form hf Some of the spots separate, others united. Mulsant says the separation of the
third spot from the ground is most frequent, followed by the separation of
the third from the fourth.
Form c. Scutellar mark prolonged and extended to the second spot.
Snh^/if cirs <>f Florida:
Pigment reduced, so that the spots are not confluent. In this it is analogous to the
subspecies floridana of McgiUfi macuhita. Pronotal pattern resolved to 4
spots in some cases.
Subspecies litiginosa Mulsant.
Specimens from Southern California in the Leng collection have the spots less con-
fluent longitudinally, but more so transversely. They also have the caudal white spot
on pronotum larger.
15
16
EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES-
Genus MACRONAEMIA Casey.
3035. Macronaeraia episcopalis Kirby.
Distribution: Western States and Canada.
The pronotal pattern in a specimen from Assiniboin, Montana, and in another from
Wyoming is reduced to 6 spots. Otherwise it is relatively constant.
Genus PARANAEMIA Casey.
3037. Paranaemia vlttigera Mannerheim.
Distribution: Colorado, New Mexico, Arizona, California, and New
Mexico.
Shows very little significant variation. Casey believes those of Colorado and Arizona
to be more slender, but with similar coloration, and has called them P.
h
I.'K,. :;.— Variation of the elytral pattern of Meg ilia macidata. c^ mode; a to y from Shawnee,
' Pennsylvania; h from Ohio and Texas.
Genus MEGILLA Mulsant.
3036. Megilla maculata DeGeer. (Figs. 3, 4.)
Distribution: United States and Canada, except Pacific coast.
This species is more constant than the other spotted Hippodamini (fig. 3), as indicated
by the following count of 321 individuals from Shawnee, Pennsylvania.
Normal, 310.
Form a. The elytral spot at 3/4 on the suture
resolved to a spot on each elytron free
from the suture; 4 individuals.
Form b. 1 + scutellar mark; 2 individuals
(fig. 3,/.)
Form c. An extra spot between 1, 2, and the
scutellar mark; 1 individual (fig. 3, c/) ;
1 also seen at Cold Spring Harbor, New York.
Form d. 3 + 5; 1 individual (fig. 3, g) ; I also from Texas.
Form c. Spot 2 resolved into a larger internal and a smaller lateral spot (fig. 3, fe).
There was a case of a slight deposition of pigment along the vein between 1
and 2 and in another between 4 and 6, in each case upon the right side only. Also
one case of 2 + 3 on left side only.
Form/. Scutellar mark + 2. Not taken in the Shawnee lot, but 1 seen from Texas
and 1 from Ohio (fig. 3, h).
The typical species is found only in Cuba. It has but one continuous
area of black pigment upon the pronotum. The two subspecies following
may be entitled to specific rank. The decision must wait for more ex-
tended collection in the Southeastern States.
Fi<;. -4.— Variation ol' the pronotal pattern
of ^let/ilia maculti/ti. b mode; n to c,
from Shawnee, Pennsylvania.
CERATOMEGILLA— ERIOPSIS- HIPPODAMIA. 17
Subspecies fuscilabris Casey.
The pronotum pattern has the two areas not confluent (fig. 4) and the spots not
greatly reduced. This characterizes all of the North American range except the south-
eastern States and Cuba. Casey believes that the specimens from South Texas are
broader, with the color-pattern the same, and has named it Megilla strenua.
Subspecies floridana Leng.
Specimens from Beaufort, North Carolina, to Louisiana are smaller. The pigment
much reduced, but the pronotum, although having the pigment reduced often to 4 spots
may in other cases show a transverse confluence, in this respect approaching the typical
species as found in Cuba.
Subjection to both 40° C. and 18° C. in the usual way failed to produce
significant modification.
Genus CERATOMEGILLA Crotch.
3038. Ceratomegilla ulkei Crotch. (Fig. 5.)
Distribution: Hudson Bay.
A monotypic genus having unique antennae and of obscure relationship.
Apparently none have been taken since Ulke found the type at Hudson
Bay. The drawing given (fig. 5) is pinned into
the Leconte collection in the Museum of Com-
parative Zoology.
5
Genus ERIOPSIS Mulsant.
3040. Eriopsis connexa Germar.
Distribution: Texas, California, and Vancou-
ver Island.
n n * • • i /» -i • , -i FIOJ. •>.— Elytra 1 pattern in
A South American species rarely found in the ccratomeguin
United States (fig. 6). It is possibly derived Fl<'j
from a spotted Hippodamia by reversal of pat-
tern. E. eschscholzii from Chili represents an intermediate condition com-
parable to Hippodamia cockerelli.
Genus HIPPODAMIA Mulsant.
The species of Hippodamia fall into several distinct phylogenetic sections,
as shown in fig. 7 and table 1. The comparative size and form of some
of the species of this genus are shown in table 2. While these differ, the
ranges overlap to such an extent that size and shape are seldom service-
able in the identification of single specimens. The differences are large
enough, however, so that the eye readily detects them in the comparison
of series. The females are uniformly larger, but differ little in propor-
tions from the males. Under H. convergens similar data will be given in
regard to two of its varieties.
18 EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES.
GLACIAUS
80WDITCHI
' } CONVERGENS
DISPAR
COCKERELLI
OREGONENSIS
SINUATA
SPURIA
TREDECIM.PUNCTATA
AMERICANA
PARENTHESIS
APICALIS
LENQI
FALCIGERA
FIG. 7.— The species of Hii>podaini
29 33.9 37
l*.5 53.8 57.5
Female
75
54 68.2 73
21 26.4 31
82.5 38.7 44.5
29 35.5 39
47.5 52.1 56.5
H. parenthesis, Stony Lake:
Male
53
56 59.9 61
19 24.2 29
32.5 40.5 46.5
30 33.7 37
51.5 56.3 60.5
Female
85
53 62.8 68
20 25.0 30
32.5 40.0 47.5
30 33.8 38
50.5 51.1 61.5
3044. Hippodamia glacialis Fabricius.
Distribution: United States and Canada.
The color-pattern (fig. 8) of this species is approached and even realized
in some cases by specimens of H. convergens in the Western States beyond
the usually recognized range of H. glacialis. Yet complete intersterility
was found to prevail in repeated tests between eastern specimens of the
two species. Whether this intersterility is bridged over by these speci-
mens in the Western States I was unable to test.
20
EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES.
The resemblance of this species to H. convergens, and especially the simi-
larity of their larvae, is such that it has probably been derived from that
older type at no very distant date. The pronotal pattern is like that of H.
convergens, but shows relatively less variation (fig. 9).
Var. A. The humeral spot
absent. In 9 out of 26, or
35 per cent of the males,
and in 6 out of 29, or 21
per cent of the females at
Cold Spring Harbor.
Var. B. Spots 4 + 5 + 6.
Several taken from di-
verse localities. Nowhere
established (fig. 8, /).
Var. C. Spots 6+4 + 5.
As above (fig. 8, /?).
Var. D. Spots 4, 5, ; nd 6
merged in one rounded
area (fig. 8, ./). Only 1
specimen seen.
Var. E. With spot No. 2;
3 cases in 55, or 6 per cent,
at Cold Spring Harbor
(fig. 8, a).
Var. F. With the extensa
mark. Only 1 specimen
at Cold Spring Harbor
(fig. 8, sr).
Var. G. Spots 4, 5, 6 (fig.
8, rf).
Var. H. Without discal
spots on pronotum. Only
1 specimen from Cold Spring Harbor.
cialis of the Western States.
Var. /. Median white spot upon head extending to eyes,
western specimens (fig. 10).
FIG. s. — Variation of elytra! pattern of ffippodamia
b = mode.
Also seen in the H. convergens var.
Especially characteristic of
3T
d
FIG. 9. — Variation of proiiotal pattern of IIii>podatnin ijlncnilis. it = mode.
Fi<;. 10. — Variation of color-pattern of head of Hippodamia i/lncinlix. d = mode; K from Omura, Kansas;
c to e from Cold Spring Harbor, New York.
The appearance of spots 2 and 3 and of the scutellar mark, which is
occasional, may be looked upon as reversionary. The extensa mark is also
met with in H. convergens var. extensa and is a case of parallel variation.
HIPPODAMIA.
21
HEREDITY.
The three females in table 3 with unknown mates show clearly enough
that the presence or absence of spots 1 and 2 is inheritable. No. 453 had
the transverse band broader than usual and its progeny show the inherit-
ance of this condition, for in some of the offspring- the mother was exceeded
in this respect and none of them show the slightest tendency to the separa-
tion of the component parts. The heredity of spots 1 and 2 is segregative,
with a few intergrades. The shortness of the pedigrees leaves the ques-
tion of dominance unsettled.
TABLE 3.— Heredity in Hippodamia glacialis.
Mother.
No.
1
•2
1 and 5
No.
Pattern.
Present.
Very
small.
Absent.
Present.
Absent.
Sepa-
rate.
I'nited.
248s
1 absent, 2 present,
4 + 5
S 3
(1
5
7
1
3
5
434
1 present, '_' absent,
4 + 5
31 L>5
i>
:;
1)
31 0
:;i
453s
1 present, 12 absent,
•1+5
14
13
0
1
0
14
0
14
3046. Hippodamia convergent Guerin.
Distribution: North America.
This is a wide-ranging species which is highly variable. For reasons
given later I have thought it best to reduce to the status of varieties several
of its derivatives which have received specific names. The variation (fig.
11) is strikingly parallel to that in Hippodamia septempunctata and to a
less degree to that in Adonia varieyata. The varieties of these two Euro-
pean species have been well studied and named. This is not the case with
the American H. convergens. I have indicated the correspondence of these
varieties by the sign of equivalence ( - ) used by mathematicians. The
correlation of pronotal and elytral patterns is low enough to make it desir-
able to treat them separately.
Types of Patterns in Elytral Spots.
Spots £, 1, 2, 3, 4, 5, 6. Typical.
Spots A +3 + 1, 4 + 5, 6, va>-. quinquesignata Kirby.
Spots J +3 + 1, 4 + 5, 6, with pronotal discal spots, var. puncticollis Casey.
Spots i -|- 3 -|- 1, 2, 4 -f- 5, 6, H. septemmaculata var. continue/,.
Spots | + 3 + 1, 2, 4, 5, 6.
Spots £ -f-3, 1, 2, 4 + 5, 6, var. caseyi (new variety) - >A. variegatavar. ustiilata Weise.
O H. tredecimpunctata var. contorta Weise.
This common variety is generally called lecontei Mulsant, the description of which
calls for a pattern quite different, which is given below. This variety is so well
known that it seems best to rename it.
Var. dejecta (new variety). Formula as in var. caseyi, but spot 1 small and 1 -(- 3
much less heavily pigmented.
Because of its interesting relation with var. caseyi, discussed later, this variety is
given a name.
EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES.
FIG. 11. — Variation of elytral pattern in Hippodamia conreryens.
HIPPODAMIA.
23
Spots
Spots
Spots
Spots
Spots,
Spots
Spots
Spots
Spots
Spots
Spots
Spots
Spots
\ + 3, 1, 4 + 5, 6.0 H. septemmaculata var. viadri Weise.
J + 3, 1, 2, 4, 5, 6, = = H. septemmaculata var. puyknlli Weise - H. tredecim-
punctata var. triloba Weise.
& + 3, 1, 4, 5, 6, =c= H. septemmaculata var. oblonga Weise.
i, 1, 2, 3, 4,5 + 6, =0= H. tredecimpunctata var. c. nigrum; rare; California and
Nevada.
4, 1, 2, 3, 4, 5 + 6, var. juncta Casey; taken in Sonoma County, California, and 1
specimen from Stony Lake, Michigan.
i, 1, 2, 3, 4+ 6, 5, rare; Pacific States.
i, -)- 3 + 1, 2, 4 -) 5 -j- 6, rare; Rocky Mountains.
£, 1,2, 3, 4 + 5, 6 z H. tredecimpunctata var. spissa Weise =:=#. septemmacu-
lata var. aestiba; common in Western States.
J, 1, 4 + 5, (>, pseudoglacialis (new variety); New Mexico and northward.
J + 3 + e, extensa Mulsant, Western States.
i + 3 + e, 2, 4, 5, 6.
£ + 3 + e, 2, 4 + 5, 6.
J + 3, e, 2, 4, 5, 6.
FIG. 12 — Variation of elytral pattern of the quindecimmaculata varieties. c =
mode; «, from Lake Superior; /*, California; c, St. Louis. Missouri; , luwa
city, Iowa; e, Southern Illinois; /, Kaiaiack Butte, Washing-ton: h, Keeler,
California; /.St. Louis, Missouri.
Spots J + 3, e, ef, 2, 4, 5, 6.
Spots £ + 3 + e + e', 4, 5, 6, lecontei Mulsant.
Spots £, 1, 2, 3 + q, 4, 5, 6, quindecimmaculata Mulsant (fig. 12) ; Central States.
Spots 4., 1, 2, 3, q, 4, 5, 6; very rare; Central States.
Spots J, 1, 2, 3 + q + q', 4, 5, 6, difficult to distinguish from 3 + q, but known to exist
from a few specimens with reduced pigment.
Spots J, 1, 2, 3 + g, 4, 5, f>, quindecimmaculata A Mulsant; very rare; Central States.
Spots \, 1, 2, 3 + q, 4 + 5, 6, quindecimmaculata D Mulsant; Missouri Valley; very rare.
Spots J, 1, 2, J + 3 + q, 4, 5, 6, quindecimmaculata C Mulsant; Missouri Valley; very
rare.
Spots \ + 3 + q, 4, 5; 1 specimen from Fairfield, Washington.
Spots i, 1, 2 + q, 3, 4, 5, 6; very rare; 1 specimen from Kamiack Butte, Washington,
upon one side only.
Spots £, 1, 2 + q + 3 + \, 4, 5, 6; very rare; Missouri Valley.
Spots \, 1 + q + 3, 2, 4 + 5, 6; 2 specimens from Keeler, California, and St. Louis, Mis-
souri, respectively.
With the comma-mark as in Neoharmonia venusta var. A.
Spots 1, 2, 3, 4, 5=c= septemmaculata var. vorax Weise. Eastern as well as Western
States.
Several spots lacking, convergens C Mulsant; Western States.
Mark \ only, obsoleta Leconte; Pacific States and Western Mexico. Most numerous
in western Oregon outside the humid region. Extends in reduced numbers
through Arizona to the Great Plains, giving way to var. C Mulsant gradually.
Spotless, with obsoleta; rare; = H. tredecimpunctata var. signata Paid. = ^= H. septem-
maculata var. r libra Weise.
24 EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES.
Var. moesta Leconte:
The black area extended so as to leave only a small basal lunette and a small area
between 4 and 6 of the reddish ground-color. Northern California to Vancouver Island and
British Columbia between Hope and Okanogan. Limited to the humid Pacific Coast
region. I have been unable to obtain living specimens. There is reasonable doubt as to
whether this pattern may not constitute a distinct species, especially since at Dilley, Ore-
gon, where the spotless variety prevails, one has been taken. It is clearly a melanic
derivative from a spotted Hippodamia. Two specimens with pigment reduced enough to
reveal the unobscured pattern are shown in fig. 13. While they do not agree in showing
one direct line of development, it is probable that it is through var. quinquesignata. It
is likely, moreover, that the beetles have some such pattern when newly emerged from
the pupa, as Miss Isabel McCracken has shown for the melanic variety of Melasoma
scripta, and that the variation in these when known will make the ancestry of var. moesta
clear. The modification experiments uponH. convergens prove that a cold environment in-
creases pigmentation. The degree of cold was such, however, that the beetles suffered
more or less damage, and still they fell far short of the melanism of the variety moesta.
Moisture alone produced no effect. For this reason and because Dilley, Oregon, has typical
var. moesta rarely along with the spotless H. convergens, I believe that H. moesta is an
inherited condition and not an "ontogenetic species." It remains to be seen whether it
belongs to the intergenerating unit of H. convergens or not.
FIG. i:!.— Variation of color-pattern of var. moesta. with twointergrades.
e =-- mode ; b, from Humboldt County, California.
Examination of these varieties shows that they are the several combina-
tions of a number of characteristics, as follows:
1 to 7. The mark £ and the spots 1, 2, 11. The confluence of 1 and 3.
3, 4, 5, 6, respectively. 12. The confluence of 4 and 5.
8. The new spot e. 13. The confluence of 4 and 6.
9. The new spot q. 14. The confluence of 5 and 6.
10. The confluence of £ and 3. 15. The melanism of var. moesta.
The combinations of these characteristics produce the different vari-
eties given and the numerous ones not given, characterized by loss of
certain spots. The distribution of some of the characteristics is given in
tables 4 and 5.
The pronotum is subject to a similar remarkable variation (fig. 14), and
this, strangely enough, is not highly correlated with the coloration of the
elytra. Spotless elytra, as well as the typical spotted pattern, are asso-
ciated with all or nearly all of the pronotal patterns. The typical pronotum
is black, with 2 light convergent discal marks and a narrow light margin.
The black area is slightly emarginate mesocephalad and the white margin
is slightly narrower laterad and broader cephalolaterad and caudolaterad.
The convergent marks may, on the one hand, disappear, or, on the other
hand, break through to the margin, generally at a point in the continuation
HIPPODAMIA.
25
of the direction of its greatest length. Occasionally it opens caudad of the
lateral process and at other times at both places. Still more rarely it
breaks through at a third point more directly cephalad. Table 5 shows
the geographical distribution of these characteristics and its association
with the elytral pattern.
As Kellogg and Bell (1904)
have shown, the variation
is continuous from large
pronotal dashes through
small ones to none at all.
The presence or absence
of pronotal dashes serves
to distinguish specimens
in collections from some
localities, but not in the San Francisco Bay region.
Fin. 14.— Variation of pronotal pattern, a. i>, d, e, from pilley,
Oregon,- c, Fail-field, Washington; /to j, Berkeley, California.
TAISLE 4. — Elytral pattern in Hippodamia convergens.
Locality. No.
Spot-
less.
Some
Spots
absent.
12 spots
pres-
ent ; no
con-
tinence
44-5
H+.
Var.
e.\-
ten-
sa.
™*
Var.
qllill-
cim-
mac-
nlata.
i ilac-
ialis
pal-
tern.
1+2
5+6
^
Palo Alto, Cal. (K.
and B) 1,033
P.ct,
\ —
P. ft.
6.09
P.ct.
93.6
P.rt.
1—
P. ft.
0
P.i-t.
0
P.ct.
0
P.ct.
0
P.ct.
0
P.ct.
1—
P.ct.
1—
'i—
Kamiack Butte,
Wash 15 415
1—
1 5 :{
5.91
6.3
30.2
3.7
s.o
1—
1—
0
0
0
Marsh Hill, Fair-
field Wash 1,406
1—
8.6
'.9
2.4
9.8
0
0
0
0
0
TABLE 5. — Elytral pattern in Hippodamia convergens.
Locality.
No.
Per cent
spotless.
Per cent
some
spots ab-
sent ; no
con-
fluence.
Per cent
typical
spots
present;
no con-
fluence.
Percent
some
spots
con-
tinent,
Chewelah, Wash
191
0
27.2
1—
72.2
Alount Carleton ^'ash .
359
0
1—
0
99+
S pokane and Cheney, Wash. .
Fairfleld Wash
107
1 ,406
0
1—
5S . S
33.7
5.6
8.6
:!5 5
50.2
sii-ptoc Buttt- Wash
0
81.3
0
is i;
Kamiack Butte, Wash
< lolclenclale \\'a^li. ...
15,415
159
1—
0
10.7
11.9
10.7
84.9
4S.4
:{.!
Portland Ore"'.
10
0
10
90
0
Dillev ( )reg
895
94.9
l.i'
1—
0
Berkelev Cal
6T3
45. ti
4.0
48.8
1—
Oakland, <_'al., A
632
9 2
1—
0
0
Oakland ( 'al B
76
;;: 5
0
68.4
0
Watsouville <'al
68
51.4
0
48.5
0
Santa ( 'lara Valley, Cal
Mendocino County ('al
425
84
2.3
0
6.3
3.5
90 :;
9(1.4
]
1)
Licking Fork Oal . .
17
5.8
70.5
23.5
0
lledlands, Cal
San Diego Cal
71
4
12.0
75
1.4
0
S5.!l
25
0
0
I'alo \ltii Cal
1,033
1—
(i.09
98. (i
1.7
San .lose Cal
267
1.1
1.8
97.0
0.
Coolidfie. N. Mex
Tepexpam, Mexico
Bartlesville ( )kla
75
201
19
0
5
0
14. li
17
0
32.0
78
100
53. :i
1—
0
Ston\" I(ake !\Iich
20
0
0
95
0
Cold Spring Harbor, N.Y . . .
203
0
1—
99+
1—
26 EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES.
TABLE 6. — Variation of pronotiim of Hippodamia convergens.
Locality.
Elytra!
spots.
No.
With
dash.
Marginal dash.
Margin.
With-
out
dash.
Con-
fluent
cepha-
lad.
Con-
fluent
laterad
Con-
fluent
cepha-
ladand
laterad
Com-
plete
and not
con-
fluent
With
dash.
1 11CO111-
plete
ceph-
alad.
Incoin-
lucom- plete
plete ceph-
laterad alad
and lat-
erad.
Chewelah, \\':tsh
Do
Some a b-
xent.
Some eon-
fluent.
Do
Present
Some a b-
sent.
Some eon-
fluent.
Present
Some a I) -
sent.
Some con-
fluent.
. ..Do
52
138
139
6
63
38
14
94
US
200
466
107
118
2,372
100
100
154
8
38
850
383
42
750
33
28
643
32
13
84
12
4
58
4
24
11
40
1!)
12
19
202
200
P. ct.
94
100
99
100
94
92
100
97
100
93
98
96
9'
96
97
99
100—
100
100
100-
100
98
42
100
(IS
100
97
100
100
100
100
100
50
100
73
0
37
25
100
100
UK)
P.ct.
U
0
1
0
(•>
8
0
3
0
7
2
4
• >
4
3
1
1—
0
0
1—
1—
• >
58
0
32
0
3
0
0
0
0
0
50
0
27
100
63
75
0
0
0
P. ct.
6
0
1
0
3
3
0
1
1
1
2
2
1
4
0
0
0
12
5
::
0
0
1—
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
P. ct.
II
0
0
0
0
I)
0
0
(1
0
0
0
0
1—
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
P. ct.
0
0
0
0
0
0
0
0
0
0
0
0
0
1—
0
0
0
0
2
10
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
P. ct.
88
86
41
100
97
ti:!
100
98
11
89
89
86
88
P. ct.
0
u
0
0
0
5
0
1
0
i
0
0
0
P. ct. P. ct.
6
0
14
0
58 0
0 0
0
0
29
0
0 0
0
0
88
9 0
0
9
0
12
0
11 0
Mount ( 'arlton,Wash
Spokane a nd Chenev,Wash .
Do
Uo
Fail-field, Wash.. 1907. .
l>o.
1 >o
Fail-field, Wash.. 1H07..
Steptoe Hutte, \\'ash . .
Some a b-
sent.
Some con-
tinent.
Present
Some a b -
sent.
Spots land
ti absent.
Some con-
fluent.
Present
Absent .
Ho..
Kamiaek liutte, Wash
Do . . . ....
96
1 )( >
99
94
100—
76
74
82
100
7<>
HI
94
3
700
97
85
100
100
100
100
0
100
73
100
21
92
100
100
99
0
5
1—
0
0
0
0
0
9
0
7
0
0
0
0
0
0
0
0
18
0
21
8
0
0
0
1 0
1 0
o o
0 12
10 0
5 1 —
0 M
5 19
4 71
0 li
18 71
0 0
0 3
15 0
(1 0
o o
o o
0 0
0 100
0 0
0 9
0 0
11 47
0 0
0 0
0 0
0 0
I ). > . .
(ioldendale, Wash
Portland, ( >reg. . .
Oil lev, Oreg
Some ab-
sent.
Absent
Present
Some a b -
sent.
Absent
Present. . . .
Do .
Herkelev and Oakland, ('al.
Do
Do..
Watsonvillc, Cal ..
Do
Absent
Santa Clara Vallev, Cal
Do..
Present
Some a b-
sent.
Absent ... .
Present
Some a b-
sent.
Present.. . .
Do
Do
Mendocino ( 'onnty, ( 'al
Licking Fork, Cal
Do..
Kedlands, Cal. .
1 i, ,
Absent.. . .
( 'ooliilLie, N. Mex
Do.. . .
Present
Some a b-
sent.
Some con-
fluent.
. . Do
Do .
1 Hirango * 'olo
Mill'ord, I'tali
. . . Do
Stonv Lake Mich .
Present
Cold Spi-insi' llarlior. N.Y. .
Tepexpam, Mexico
Total
Do
Do..
7,824
89
11
1
1—
1—
80
2
8 8
1 i
HIPPODAMIA. 27
Fig. 15 shows the variation in the pattern in the San Francisco Bay
region.
Subspecies of the mountains and high latitudes has a larger percentage
of the characteristics of J -f 3, v + 3 +1, 4 + 5, and the absence of pronotal
dashes and reduction of the light margin in the pronotum.
I
a
Fi(i. 1">. — Variation in color-pattern ot head ol'
Hippodamia runrrriji-nx. <• = mode: t'l.">,41.~>
individuals I'roni the to))
3
1
5
9
Kamiark Butte, Wash
Palo Alto Cal
15,415
1 0:i:{
P. ct.
0 06
.29
P. Cl. P. <•!.
O.'JO 1.08
78 1 4(>
P. <•/.
:$.fi4
.78
P. t-t.
8.62
87
/'. ,-f.
•J7 -•;
•'•' :;
P. <•/.
59.2
93 9
Cold Spring Harbor, N. Y. .
202
0
0 0
0
0
1-
99 +
30
EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES.
The variation of the number of spots is shown in table 7. At Palo Alto
(data from Kellogg and Bell, 1904) and at Cold Spring Harbor the polygons
are not regular, but show a normal condition of 6 spots, with a scattering
few having aberrant numbers. I have grouped 25 specimens, said by
Kellogg and Bell to have 1 or more extra spots on one or both sides, with
those having 6 spots, because the irregular position of these spots and my
experience with living specimens makes me believe that such spots are
nearly always, except when at e and q, of ontogenetic origin. The poly-
17.— Relative frequency <>t
the several spots in the semis
/fi/ipodaniia. Broken line, col-
lection of KellOKs and Bell from
Palo Alto. California: entire lin« .
collection from Kamiack Butte,
Washington.
gon for Kamiack Butte might have shown about 0.5 per cent, with a seventh
spot e, but I have not put these in, because no accurate account can be
made of spot e, as it may be entirely covered with pigment from spot 3 and
the scutellar mark. Now, in contrast to the condition at Palo Alto and
Cold Spring Harbor, we have at Kamiack Butte a polygon not greatly un-
like the half-Galton curves found in some petal-counts. Yet the real nature
of the variation in the three cases must be the same. Such an instance
shows us that the distinction between continuous aud discontinuous varia-
tion is not a sharp one.
The order in which the spots disappear has proved to be a matter of great
interest. I have tabulated the data given by Kellogg and Bell (1904)
Palo Alto, California, in table 8, and fig. 17 (broken line), but have
numbered the spots according to Weise. There is no very pronounced
order of disappearance here, the most prominent feature being the persist-
ence of spot 2. But at Kamiack Butte (table 8, fig. 17) , a very different
condition prevails. Here spot 1 exhibits a strong tendency towards disap-
pearance, and this happens in spite of the fact that it is in company with
several varieties having spot 1 unusually large and in some cases confluent
with spot 3. Spot 6 follows it in order of non-development and then spot
2, which at Palo Alto was most persistent. It is evident, then, that not
only is there a definite order, but that this differs from place to place. The
HIPPODAMIA.
31
spots are, therefore, to a considerable degree independently variable units.
Yet if we take into consideration the combination of spots, we shall find
there is some ' ' coupling. ' ' Spot 1 is most frequently the only spot absent,
while spot 3 is most frequently absent as one of three. It is quite possible
that the order of disappearance would be just the reverse of the order of
persistence. Table 9 and fig. 18 are designed to test this matter and also
the question of coupling between spots. Along the horizontal scale I have
represented the various combinations of spots in the order of frequency of
their disappearance. The solid line indicates the frequency of these sev-
A
Spots
11211011111311224134
6 22 34254 5363626
3 66 66 5
154112
4 5234
5 45
Lacking 3583664327313241241 168 1.57 73 72 41 32 20 25 19 18 14 10 9 8 7 7 6 5 4 1
Having 04310241 0109101 33 90 2 5 613 66 04 1
FIG. is.— Correlation of loss <>f spots.
2 3
5 r,
i i
8 26
1 3 5
346
4
0 0 0 = 5073
1 4 6 = 211
eral patterns. Now, in the dotted line I have represented the frequency
of the same combination of spots present. We see from it that spot 4
alone is less frequently lacking than spot 2 alone, yet spot 2 alone more
frequently persists. Similarly, spots 5-6 are less frequently lacking than
4-5, yet 4 and 5 each persist more frequently. The couplings of pairs of
spots in disappearance in the order of frequency are 1 and 6, 1 and 2, 1
and 3. These pairs do not frequently persist alone, and the order of pairs
in persistence is 4 and 5, 2 and 3, 3 and 5 ; these pairs are not frequently
lacking. The coupling of trios in order of disappearance is 1-2-3, 1-4-6,
1-2-6 ; these groups rarely persist alone. Thus it is roughly true that the
more persistent groups are less likely to be frequently disappearing groups.
If the confluence of elytral spots 4 and 6 represented merely an overflow
of pigment, because of increase of size of spots, it should be found in H.
quinquesignata or boivditchi, yet it is only rarely met with in cases of
enlarged 4 -f 5 in the mountains. It is more frequently found in Califor-
nia in regions where the spotless variety is present.
32
EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES.
The confluence of spots 5 and 6 is an independent variation. The speci-
men that Major Casey has from Sonoma County, California, and the one
I have from Stony Lake, Michigan, are well marked. It is very rare, with-
out intergrading conditions, and constitutes a distinct position of organic
stability.
TABLE 8. — Spots lacking in Hippodamia convergens.
[Percentage of hectics in which each spot is lacking.]
1
Locality. No.
Spot 1. Spot 2.
Spot 3.
Spot 4.
Spot 5.
Spot 6.
Palo \lto ( 1jil .. ... 1,033
:{.5 0.9
2 7
:', 5
:; 1
:; !i
Kainiaek Buttc. Wash 15,415
Cold .Spring Harbor, X. Y 202
'IV| ic \pain Mexico . 200
:!ti.2 7.7
0 0
110 7.0
4.1
0
7.0
2.4
0
12.0
1.5
0
13.0
9.3
j
19 0
The loss of the pronotal dashes (fig. 14) and the extension of the black
pigment on the pronotum is well marked in specimens from California
Strangely enough, they affect the spotless beetles most. One might
conclude that the result is compensatory for the lack of pigment in the
elytra, but in Oregon, where spotted elytra are found, the black pattern
of the pronotum is reduced, as shown in fig. 14, a to e. There are prob-
ably, therefore, two different causes for the reduction of pigment in the
pronota and in the elytra. The only case of an opening of the pronotal
dashes (fig. 14) to the margin laterad without communication cephalad
was at Fairfield, where the forward opening is not nearly as common as in
Oregon. Apparently the line of development is different in eastern Wash-
ington from that of western Oregon.
TABLE 9. — Combinations of spots present and absent in H. convergens from Fairfield, Wash.
Total.
Present.
Spots.
. \liscnt.
Total.
|
P. el. of
sum of
totals.
In
sixes.
In
fives.
In
fours
In
trios.
In
pairs.
Sin-
giy.
Sin- In
-ly. pairs.
In
trios.
In In
fours, rives.
In
sixes.
9,828
11,779
14,233
15,191
15,048
13,992
Av
9,121
9,121
9,121
! 1.121
9,121
9,121
615
4,166
3,871
4,19]
4,190
3,957
69
1.131
1175
1,247
1,265
621
13
283
219
512
387
269
ID
69
44
107
80
22
0
9
• i
13
5
•>
1
9
5
1
(i
:i,5s:; l,_'5s
32 196
327 .T>2
7 80
S 62
211 70li
54S
27X
342
49
174
292
15(i 32
97 23
122 29
5!) Ill
Xli 27
144 30
10
10
10
10
10
1(1
5,587
636
1,182
224
367
1,423
36.2
(.1
7.7
1.5
2.4
9.3
9,121
3,49K.3
884.7
280.5
55.3
5.3
6' r.1.7 442.3 2X0.5
110.7 26.7
10 9,419
JO. 2
CORRELATION.
The correlation between the confluence of spots 4 and 5 with the con-
fluence of spot 3 and the mark J- is represented in table 10, and of 4 and 5
with the confluence of 1 and 3 in table 11. These tables show that the cor-
relation falls far short of the current notion, expressed in the systematic
literature, that these confluences are definitely coupled.
An examination of table 6 shows that where black spots on the elytra
are absent the pronotal dashes are also absent in a large number of cases
HIPPODAMIA.
33
in some California localities, but not in others. At Coolidge, New Mexico,
where spots are confluent, the pronotal dashes are absent in a large propor-
tion of cases and are present where there is no confluence. This is also
noticeable in some small lots from Colorado and Utah, but in the Pacific
States this difference is not marked.
TABLE 10. — Correlation of relation of spots % and 3 with relation of spots 4
and 5 in Hippodamia convergens at Fairfield, Washington.
4 ami ">.
Relation, '._, anil 3.
Con flu-
fiit.
Transi-
tion.
Sepa-
rate.
Absent.
Ti >tal.
Confluent
* 177
2
22
1
202
Transition . ...
1
I)
6
1
8
Separate
1 1
1
t'J9
4
118
Absent
0
0
5
tl
6
Total...
1112
3
132
7
334
* Quindecimsiffnata and
Var. oltxo/rla.
TABLE 11. — Correlation of relation of spots 1 and 3 with relation of spots 4 and r> hi
Hippodamia convergens at Fairfield, Washington.
4 and 5.
Relation, 1 and 3.
Fused.
Transi-
tion.
Sepa-
rate.
Abselil.
Total.
Fused
*64
0
0
0
64
Transition
1
0
0
0
1
Separate
f!20
3
159
0
1S2
Absent
7
0
74
g6
87
Total
192
3
133
(1
334
Var. quinquesignata.
t Var. cnseyi.
t Convergens.
\ Var. obsolete.
The lateral extension of the black area on the pronotum to the margin,
so as to make ''margin incomplete laterad," is associated, strangely
enough, with both spotless elytra and elytra with spots confluent. We
shall see later that this characteristic is subject to modification, so that
the great variation between the several localities in eastern Washington
which differ in altitude is readily understood. In fact, a lot of hibernating
beetles from Fairfield in 1907 showed far fewer specimens with the margin
incomplete laterad than those of another year.
The cephalic extension of the black area of the pronotum causing an
incomplete margin cephalad is only common in California and New Mexico
with beetles lacking the pronotal dashes, but that it is not a necessary con-
sequence of the absence of the dash is shown by the specimens from Mil-
ford, Utah.
We have, then, in different localities, a difference in the correlation and
the order of development of the pronotum and the elytra.
34
EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES.
MEASUREMENTS.
I have measured, by means of the eye-piece micrometer, the degree of
separateness or confluence of the several spots in a lot of beetles from Fair-
filed, Washington. Fig. 19 gives the result in the case of spots 4 and 5.
The micrometer units of 0.625 mm. have been used without change to avoid
the introduction of errors of reduction. In order to avoid errors of com-
binations the original classes are used, even though it makes the polygons
somewhat irregular. The reader may make his own combination of classes
mentally. Of course, since it was necessary to measure a projection of the
curved surface and as the distance measured was not always at the same
focal distance, there are errors involved. Experimental testing, however,
shows that the errors are too slight to affect the significant features of the
(n) The distance between and confluence of
ppots 4 and 5 (in units of .625 millimeters.)
(6) Males,
(c) Females,
(f?) All individuals.
(a) 14 13 12 11 10 '.18765432101 23 1 5 C 7 S 9 10 11 12 13 14 15 16
(b) 0 1 0 2 2 6 10 11 S 84 Ox! 20 1 0 1 3 4 811 15 14 13 13 2321 0 = 1.30
(c)000j4696 13 11 S 7 61210345 10 ]<; 21 13 7 7 (i 1 0 1 0 = 169
(rf) 0 1 0 3 6 13 19 17 22 19 13 7 S 3 2 2 0 5 7 9 IS :>,\ 3C, 27 20 20 8 4 2 2 0 = 324
FIG. 19. — Variation ol the distance between and confluence of spots 4 and 5 in Hippodamia
convergcns at Fuirnekl, Washington.
polygons. A novel method has been used in the construction of the curves.
0 is the case where the spots are separated by a distance less than 0.5
unit or confluent to the extent of having a connecting strand less than 0.5
unit in thickness. Increase of distance between the two spots is plotted to
the left. Increase in breadth of the connecting strand pigment is plotted
to the right.
It will be noticed that the sexes do not materially differ ; that the dis-
tance apart is more variable than the thickness of the connecting band;
that the polygon is bimodal; and that the transitional cases fall for the
most part into one or the other of the two polygons.
HIPPODAMIA.
35
Fig. 20 shows the variation in the relation of the mark ± to spot 3. The
same conditions hold as before.
( ;unl spot 3.
(6) Mules.
(<•) Females.
(rf) All individuals.
17 in i.-,
(ft) 005
(»•) 0 1 1
(fl) 0 1 G
14 13 12 11 10 987654321 0123456789 10 II 12131415161718192031
3 03313661 10 5248300136147 1314 !>:• 11 7 9 0 2 o o 0 0 0 = 152
2328505565438532022459 13 8 10 10 15 986100010 = 170
5 3 5 5 G 9 11 11 7 16 9 5 12 9 6 2 0 3 5 10 7 13202124272610 li (.; 3 0 0 0 1 0 = 327
FIG. 20. — Variation of the distance between and confluence of the mark % and spot 3 in
Hippoclamia convcrgens at Fairfleld, Washington.
Fig. 21 (of the relation of spots 1 and 3) gives a curve which is prob-
ably trimodal — a mode each for the typical species, the variety caseyi
(widely separate spots) and the variety quinquesignata (confluent spots).
(a)
(b)
(<•)
(d)
The distance between and
confluence of spots 1 and 2.
Males.
Females.
All individuals.
\
(a) 23 22
(ft) 00
(c) 01
(«f) 0 1
21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 1 2 3 4 5 6 7 8 9 10 11 12
0131362203224 11 21 16 16 21 3 0100011115014 0=111
0114V 42427404 15 20 17 12 2120001120742101 0=120
0 1 4 o 10 10 4 G 2 10 6 2 8 26 41 3329 4 2 5 0 1 0 1 1 3 1 S 5 7 1 15 0 = 213
Fi«. 21— Yiuu.tio.1 ut tlic distance between and confluence of the spots 1 and 3 in Hippodamia
convergens at Fairfleld, Washington.
The reality of the varieties is conclusively shown in fig. 21. They are
not distinguished by sharply limited unit-characters, but are centers of
variation.
36
EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES.
The variability in diameter of spot 1, shown in fig. 22, is a partial expla-
nation of the previous polygon. Here the variety caseyi and variety quin-
quesignata include these individuals at or near 15 units, while the typical
specimens are at or near 5 units.
("} 0
('') 0
('•) i>
(<() 0
(«) Diameter of spot 1.
(6) Males.
(c) Females.
(rf) AlLinriividual>.
12
•-! -1
3 5
5 0
3456789 10 11 12 13 14 15 1G 17 IN l.i :J'i :.M ;.'•.'
3 (i •"! 311122 5 12 19 22 15 10 2120 0— IF,
3 37331445 15 10 13 III 14 0 4 0 0 1 0=129
G 0 10 G 4 55 6 7 20 31 32 42 29 10 6 1 ~ 1 0=24r,
FK;. 22.— Variation in tin- diameter of spot 1 in /[iiijiui/itiitia <-1MS 0
54.03 ±
.20
13
50.71 ± 0.22
">l.77 + .23
Var. quinquesignata
,'>4.06 -t-
39
52,41 ± .38
HIPPODAMIA.
37
MODIFICATION.
Subjection of the prepupa and pupa to an ordinary poultry incubator at
40° C. resulted in no appreciable modification, nor did increase or decrease
in humidity. But an increase of
pigment was obtained by expos-
ing the prepupa and pupa to the
cold of a refrigerator (5° to 15°
C.), a cellar (15° to 17° C.), and
the intermittent temperature of
an ordinary room where the
temperature dropped during the
winter months from 12° to 18° C.
by day to 5° C. at night. The
greatest degree of pigmentation
resulted in the last case. The
result from one experiment, in
which the prepupa3 of typical
Hippodamia convergens were
subjected to a freezing tempera- <«> Diameter of spot 3. /
ture out of doors for two nights, ((^ ^envu^
was the elytral pattern shown in <) AH individuals,
fig. 25, which is much like that of
the western mountain beetles.
The other cases give the prono-
tum that is so frequently found
in the western beetles, but elytra
not corresponding to any known
variety. Fig. 26 is a composite
drawing, no one beetle showing (/'"-
show a correspondence to some
of the varieties in nature ; other features are produced only by artificial
modification, especially the pigment line between 1 and 4, which is not
the same as the vitta in Hippodamia spuria var. or H. apicalis var.
HEREDITY.
Every variety or noticeable variation which has been tested is inher-
itable in some degree. Even though the variety has been brought from a
different region, it has maintained itself in our vivarium.
The heredity of spot 1+3 shows a nearly perfect segregation. There
is a lower degree of segregation in the confluence of 4 and 5. The closest
approach to blended inheritance is in the size of the pronotal dash and the
incomplete lateral margin of the pronotum. Yet in each of these cases it
1 2 3
4 5
3 3
3 3
G
G 7 8 9 10 11 12 13
G 11 8 7 7 4 1 0 = 55
5 8 17 13 5 3 0 0 = 03
5 11 19 25 20 12 7 1 0 = 113
38
EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES.
is clear that the end positions, that of no spot verms spot of normal size in
the one case, and lateral margin wholly incomplete versus normal in the
other case, are more stable conditions; otherwise we should probably have,
as a modal condition, a somewhat shorter pronotal dash and a narrower
margin, instead of the persistence of a variety in company with a parent
species.
,
FIG. 25.— Offspring of 29.3, , exposed to inter-
mittent cold when a prepupa.
FIG. 26. — A new pattern, produced by inter-
mittent exposure to cold, which is not found
in nature. From Hippodamia conreryens.
() 10 11 !•.' j:j 14 15 16 IT 18 19 20 21 22 23 24 25 20 27 28
(l>) 0 1 2 4 12 15 37' 35 20881000001 0 = 139
(f) 0 0 0 7 12 28 35 44 20 3 1 0 0 0 0 0 0 0 0 = 150
(eO 0 1 2 11 24 43 72 7'J 40 11 41000001 0=M-J
FIG. 24. — Variation of distance from the suture through spot 3 in Hippndti-
mia converyens at Fairfleld, Washington.
(a) Distance from suture through spot 3. (b) Males. (<•) Females.
(d) All individuals.
Owing to the small number of extended pedigrees, the extent of domi-
nance and segregation in these beetles mast be examined in large part by
the comparison of the numbers in fraternities, only one parent or two
parents and one grandparent of which are known, with the theoretical
expectations under the several assumptions. In table 13 I have collected,
for convenience, the proportions to be expected under the various condi-
tions and assumptions. Thus, if a characteristic gives mixed broods when
interbred, it is not recessive, even if the allelomorph is more strongly inher-
ited. It is principally upon this criterion that so many of the pedigrees
fail to be simply Mendelian.
Where all the spots are absent (table 15), in the parent, we find this
condition ordinarily in the offspring. In the progeny of the 12 females of
this kind which had mated in nature, we find that not infrequently a few
HIPPODAMIA.
39
of the progeny have a few small spots. None were fully spotted. Com-
bining the progeny of these 12 (81 in all) and weighting small, hazy transi-
tional spots as one-half, we find spots 1 present 4, spot 6 present 5 + I,
spot 4 present 9 + |, spot 3 present 8 -|- £, spot 2 present 11 + f , spot
5 present 16 + f . This higher degree of persistence of spots 2 and 5 and
the lower degree of 1 and 6 we have also seen in the variation results in
fig. 18. Unfortunately I have no cross of typically spotted and spotless.
In 149 we have spotless x; spots 3 and 5. The progeny showed these
spots in 6 + iand 6-j-|, respectively, in the 11 offspring. A spotless
individual never gave fully-spotted offspring, nor did fully-spotted indi-
viduals ever give spotless offspring. Partly-spotted patterns can not be
considered a heterozygous condition, because in one experiment where
the parents (387) were 2 partly spotted individuals, the 20 offspring
were spotless or partly so. The spots which were present most fre-
quently in the offspring were present in the mother, but the particular
degree of spottedness was not stable, for several were wholly spotless
and several were provided with more and better spots than the parents.
We may conclude that in spottedness : ( spotlessness simple Mendelian
heredity does not prevail, but that crossing gives an intermediate con-
dition which, while not acting like a heterozygote, is yet unstable and
contributes to both conditions.
TABLE 13. —Percentage of progeny to inherit a characteristic on simple Mendelian
expectation.
Characteristic
is —
Father.
Dominant.
Trimorphic.
Recessive.
Mothei A A.
Mother A <>
Mother
A A or A b.
Mother ' < .
Mother a a.
A A
100
10(1
100
A asal mark very prominent in M, normal In progeny.
(1) In M 4 is verv near to .">. ( )f :! others subjected to cold 1 had I tr. ;>.
(5) In M' 1 + 3 became slightly confluent alter several days.
42 EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES.
TABLE 15. — Heredity in Hippodamia convergens. ( See bottom of p. 41.)
Father.
Mother.
/
Nor-
mal.
J and 3 1 and 3.
4 and 5.
4 and f>.
Ex-
tensa.
Spot 1.
No.
Offspring
of—
No.
Off-
spring
of—
Tran- Tran-
sition, sition.
+
Tran-
sition.
Tran-
sition.
+
Tran-
sition.
Ab-
sent.
It
R
K
C S H
5183
5294
430' + CS H
O
P A
.-•7 ' + 0
5x • + O
I1 A
r A
D
D
1>
D
I)
._,_,,;
B
CSH
C S H
CSH
F
F
41'"
411J
CSH
F
112-
406!
1117'
in;;-
4GS-
F
435^
CSH
F
D
201"
259'
P
413f
417'
419'
421 1,
357 i + F
408'
41S'
F
420t
427 -
F
390'
4.VJ '
391 '
F
H92 '
393J
386J
387t
:;::;• + F
4293
IH' + C
ny
F
4093
1153
F
F
F
F
F
F
422.' + F
•157'
4643
3823
439.J
R
R
R
CS 11
<) H
OB
357 + C S H
i )
PA
1' A + O
P A + 0
PA
P A
D
1)
D
1)
D
173
B
CS H
CS 11
CS H
F
F
356
356
CSH
F
369
364
369
369
403
F
375
CSH
F
D
151
151
F
352
352
352
352
11)3 + F
357
F
F
360
32
352
352
352
F
357
357
F
352
352
F
354
390
354
F
351
351
351
351
F
373
C
114
F
366
366
F
F
F
F
F
F
390
422
F
382
4
13
5
6
6
3
39
3
1
8
1
2
2
2
8
25
7
17
3
5
3
1
10
7
25
9
14
11
12
7
22
10
12
3
19
12
24
£i
25
7
9
13
13
2
1
5
21
10
20
5
7
16
17
15
3
5
39
11
26
14
2
14
4
11
12
7
2
1
1
6
5
3
1
16
21
20
7
13
M 3
M 13
M 5
M 6
F 2
FM3
M39
1
f
M3
M 1
fM 8
f M 1
M2
M2
M 2
MS
M 25
M6
M 17
F M 3
Mo
1
M
M 1
10
•>
3
1
3
4
11
....
1
3
M5
20
F M 8
KM 14
2
F M
M2
1
FM7
11
1
2
M 1
3
i
F 1
FM10
FM2
FM4
F,M3
••
3
2
6
Fl
3
M 4
4
8
M5
3
M 13
FM10
1
M 1
1
3
1
1
4
1
4
.>
1
1
M 4
10
.... ••
1
M (i
I
M
'2
"
3
9
FM4
M !»
i
r
M12
2
M13
FM13
F M|2
FM1
F M5
2
•)
1
FM13
FM2
FM 1
FM5
8
....
M"-2
M
.... M 5
'2"
i
M7
i
f 11
K M S
M 19
i
M 5
M 5
FMG
FM15
M17
FM15
FM3
F M
HI
KM 10
FM1S
5
Fl
•>
M
FM7
FMlli
MIC
FM15
FM3
FM5
10
M3
M
7
M
M10
FM15
F M 3
... F M 5
1 4
F 2
4 F3
M
6
1
F*4
K M 2
1
2
M 14
'M 7
FM18
1 M 5
1 4
3 7
1 3
3
1
FM11
FM 3
3
M F 9
FMd
4
F M 9
'i
M3
5
M4
F M 1
M
Fl
M :;
F .M 10
2
6
1
M 1
2
Si
....
FM6
3
F
1
6
FM7
1
M
M 1
M3
M5
Ml
M 1
FM14
FM21
FM20
FM7
FM13
M 1
M 1
3
M5
3
M
....
1 M 4
M
2
1
M 1
.... Ml
Ml
Ml
FM15
FM21
FM17
M7
FM13
1
'F"
M21
F20
2
F M 1
"2"
F
F
HIPPODAMIA.
TABLE 15.— Heredity in Hippodamia convergens — Continued.
43
Spot -2.
Spot 3.
Spot 4.
Spot 5.
Spot (i.
Pronotul dash.
I'ronotal
margin
incomplete.
Remarks.
Tran-
sition.
Ab-
sent.
Tran-
sition.
Ab-
sent.
Tran-
sition
Ab-
sent.
Tran-
sition
Ab-
sent.
Tran-
sition
Ab-
sent.
Small
Ab-
sent.
Tran-
sition
open
Ceph-
alad.
Lat-
eral 1.
M *
M *
(1)
f*
M*
M *
f*
M *
I'ronoluin open:
laterad also in m.
M*
M *
(-')
Spot 6 in ott'sprins?
decidedly small. M t
(3)
M *
1 offspring sk
F*
F*
(4)
2 offspring ^
F*
F*
M *
(5)
'A
F missing. It was
"almost spotless."
(5)
F* M *
«
3 offspring >(c
(3)
F*M *
F* M *
f * M *
] absent on left side
1 offspring ^
M *
F * M *
1 offspring >(c
1 offspring *. On K.
1 a p.; on L. 1 tr.
F*
M 2
1
2
M4
.
4
1
M
M 3
Ml
r M s
I'M
M •_>
M '2
M 1
M K
M13
MG
Ml.")
FM2
M5
....
5
1
M
M3
M 1
f M S
f M
M2
M2
M
M 8
M10
M 6
M 15
Fl
M 5
if' M
3
1
M
M3
Ml
r M s
i
M2
M 2
M2
MS
M15
M6
Mlo
F2
M 5
1
1
1
....
1
1
M3
M 1
f M S
r M i
M2
M 1
Ml
M7
M17
M6
M12
F2
M4
M3
M 1
fMS
f Ml
M2
M2
M 'I
1 1
M !
2
1
M 8
f M 1
2
2
1
1
5
fl
M t
1
M
M S
f]
M 2
M 1
"i'
1
MS
M 19
M6
M 17
F M 3
M5
3
M
5
F
1
M4
. . .
1
4
.">
5
M
M
•>
2
2
1
1
1
1
1
M
"i
1
M
'i
M
1
Y
•_>
2
Ml
2
1
M
M 1
I
4
•>
3
F M 1
M9
FM10
1
1
M
1
6
1
4
M 1
5
1
3
1
M
1
1
1
3
1
<>
0
1
3
1
Fl
1
1
M
M
M5
F;MG
1
1
3
M
1
M
Mil
M 4
1
M
FM6
M 1
F
F M 4
M 2
F
F M 2
5
1
3
Fl
M2
f Mil
M 7
17
3
2
M~3
fl
FM6
12
2
4
13
4
M17
3
5
M 4
i
3
7
1 f3
4 4
1 M 17
M 1
4
4
F M 4
M9
Ml
Mo
FM7
M5
S
M 12
M 2
F M 2
"3'
3
M 15
F M3
M2
M 7
3
8
2
j
M 3
F
M 12
9
6
3
11
4
9
1
1
....
M3
•>
' i
M
M 3
FM7
M
2
1
2 1
1 FMil
2
2
F3
1
1
2
F M~10
f
1
5
M 3
M
M f>
M7
3
"2'
Irs
i
1
F4
F
1
1
M3
M42
M 1
.")
17
10
F M 5
M13
.
M
i
1
1
4
M
1
Ml
FM 12
18
FM16
FM2
M9
i'
M
F
....
1
44 EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES.
The convergent dashes upon the pronotum were shown by Kellogg and
Bell (1904) to vary in size down to absence, and my observations confirm
this. No high degree of segregation is expected, then, in inheritance, and
none is found. Where the parents have intermediate dashes, the progeny
also have, although some may be just large enough not to be classed as
small in the table. The inheritance, then, is blending, but with so high
a variability that both absence and a considerable size may occur in one
fraternity.
The condition of pronotal dashes communicating with the light margin
is inherited in an average of 27 per cent, when the one only known parent
has the characteristic. Where the other parent does not have it, as with
149?, none of the offspring have such a communication. Where both
parents have the communication, as in 435, then 6.5 in 11 possessed it.
There is, therefore, neither dominance nor trimorphic heredity, but sub-
ponderance.
The data upon the incomplete margin cephalad is only adequate to
show that this character is inheritable and shows some segregation. The
incomplete margin laterad is classified upon an unsatisfactory basis, since
so many individuals have the margin almost incomplete. We have further-
more to deal with some modification. Yet it is clear that the character-
istic is inherited in part and it seems toigive us continuous variation. It is
quite possible that intermediate degrees are discriminated against in devel-
opment and that either a large lateral projection or a very slight one is
favored, as the facts of variation and distribution would cause us to suspect.
If this species as here constituted is ever to be dismembered, it is most
probable (aside from the removal of variety moesta) that variety quinque-
signata and variety caseyi will be removed as H. quinquesignata. There
is some ground for this step, although, considering everything, I have not
chosen to make it. My experiments show a partial intersterility between
specimens of variety caseyi of full pigmentation and eastern specimens of
H.convcryens. But there was interfertility between specimens with the same
confluence in a lesser degree and having spot 1 small (the variety dejecta]
and eastern specimens of H. convergens. I have only hesitated from the
division because I do not know whether variety caseyi and variety defecta
may not be interfertile. The presence of intergrades causes me to suspect
that this is not only so, but that they habitually interbreed. At any rate,
this seems to be a point at which this species may in the future divide to
give us two species, even though it may not yet have done so.
HIPPODAMIA.
45
3036 a. Hippodamia bowditchi, new species.
Distribution: Northern Rocky Mountains.
The type (fig. 28, rf) and 5 cotypes (fig. 28, 6, c, c,f, g) of this species were
collected from goldenrod August 12, 1904, on the bank of the river at St.
Maries, Idaho. The pattern is comparable to that of H. convergens and vari-
ety quinquesignata and would be considered a variety of that species but
for the distinct hiatus between the 4 specimens of variety quinquesignata
and 11 of other varieties of H. convergens, taken in the same lot, on the one
hand, and the 6 in question on the other hand. The black bands of quin-
quesignata are here much enlarged; the intermediate band is thicker in the
baso-apical direction than the space between it and the basal band. The
wide basal band is nearly uniform in width and thus shows little evidence
of its component spots. It shows no rounded projection at the position of
spot 3. Spot 2 is absent and the apical spot is much enlarged. The inter-
mediate band is so enlarged as to obscure its compound nature and its apical
margin shows no angulation. Its basal margin has an angulation, but no
restriction is produced in the band. The band extends far toward both the
suture and the costal margin and shows a straightened edge in these
directions.
9
. 2s.— Variation of color-pattern of Hijipodamin boirditchi. d= mode; 6 to .
Var. y.
Spots 1, 4 + 5 + 6. Rare, Idaho. Nowhere established (fig. 29, n).
Var. e.
Spots 1 absent, 4, 5, and 6 reduced. 2 in 759 at Fairfield, Washington; Colorado
(fig. 29, g).
Subspecies of Colorado: Reduction is most manifest in Colorado, a par-
allel to the condition in Hippodamia apicalis in Colorado. Whether it is
local to some part of Colorado, as is probable, or not, can not be told
because of the former pernicious habit of labeling by States only.
The confluence manifests itself in each individual either as 1+4 +5 or
5+4+6, and never at Fairfield involving all 4 spots even in a slight degree.
The two varieties are therefore distinct in this locality. In Vancouver
Island, however, the combination is found.
HIPPODAMIA.
47
The pronotum is much less frequently subject than that of H. conver-
gens (see fig. 30) to a reduction of pigment in such a way that the con-
vergent light mark is confluent with the light margin. This was found in
FIG. 29.— Variation of elytral pattern in Hippor/amiaspuria.
a
FIG. 30.— Variation of pronotal pattern in Hippodfimia xpuria. Mode = c tx> .?.
FIG. 31.— Variation of head-pattern of Hippodfimia xpuria from Dilley, Oregon. 6 = mode.
only 5 in 759 at Fairfield. On the other hand, there was one specimen in the
Fairfield lot in which the convergent mark extended to the caudal margin
of the pronotum and another in which it very nearly did so. In each of
48
EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES.
these cases the pronotum was lacking pigment at an independent center—
the caudal margin of the pronotum. The variation of the color-pattern
of the head is given in fig. 31-
HEREDITY.
Table 16 epitomizes the results of the heredity experiments with respect
to the elytral pattern. No. 368 ? has a pronotum with pronotal dashes open
to the margin cephalad. None of the 18 offspring possess the character-
istic. Since the same characteristic is inherited in H. convert/ens (375?),
it is probable that its lack in the offspring here is the result of recessive-
ness or subponderance.
TABLE 1(>. — Heredity in Hippodamia spuria.
[For description of form of table and abbreviations sec table 15, pp. 42, 13.]
Father. Mother.
No.
Sutnral pigment.
1 and 5.
1 and "i.
."> and fi.
No.
oil-
spring , No.
of—
( .11-
sprintr
of--
Short.
Jntcr-
ine-
diale.
Long
Sepa-
rate.
Ap-
proach
Tran-
sition.
+
Sepa.
arate.
Tran-
si-
tion.
'"I"
Sepax
rate.
Tran-
sition.
•
F
1)
2i!2 '
UK) •
+ ?
:-;s:; <
+ ?
4iil '
4 S'.l •
:;so <
4373
112 '
44,5 !.
|:!2 '
433^
F 3«S ,
D 227 ;
227 2H2 ;
F 400 }
F 383 ;
3S3 4
M .')
FM1
1
1
1
4
FM 5
FM2
F M 5
FM4
1
3
1
K:;
In the elytral pattern the table shows that the sutural mark is inherited
segregately, with some intergradation. We have two centers of variation,
but not two unit-characters. The long sutural mark is neither recessive
nor dominant, nor is there any regular dominance in the relation of spots
4 and 5. There seems to be a preponderance of short sutural pigment
and of 4 + 5, which are more common than the opposed conditions.
3048. Hippodamia oregonensis Crotch.
Distribution: Cascade Mountains.
Although the pattern of this species (see fig. 32) is parallel to that of
H. convergens var. quinquesignata, a collection of the 2 from Pinnacle
Peak, Washington, shows a difference in form of body and shape of the
spots. This makes it probable that it has been derived from H. spuria
by the addition of the banding character. The possible influence of
HIPPODAMIA.
49
the mountain environment will later be discussed in this connection.
The vittate tendency is much more marked here, as might be expected,
than in H. convergens var. quinquesignata, nearly all specimens showing
some evidence of it. The absence of pronotal spots is another result to be
expected from the mountain environment.
The basal band is the chief differential from H. spuria. Specimens of
that species differing only by absence of pronotal dashes are often labeled
H. oregonensis. Such specimens should be considered a variety of H. spuria,
as presence or absence of pronotal spots alone is a character of less distinc-
tion in Hippodamia than presence or absence of the basal band.
Form a. Spots £+1, 6+4+5, Pinnacle Peak, Washington.
FIG. 32.— Variation in color-pattern in H. oregonensis. c = mode; 6, from Oregon; c to e, from
Pinnacle Peak, Washington.
FIG. 33.— Variation in color-pattern of H.cockerclli. a, from Colorado; 6, from Yellowstone Park.
3048 a. Hippo Jamia cockerelli, new species.
Distribution: Colorado to Wyoming.
This species resembles H. spuria, except in color-pattern (see fig. 33).
This is remarkable in possessing vittaB and banding in combination. It is
the Rocky Mountain equivalent of H. oregonensis of the Cascade Moun-
tains. The two mountain systems have given two different mountain
species derived from H. spuria. If intergrades are ever found it will prob-
ably be at the convergence of the two mountain systems in British Columbia.
The type is in the U. S. National Museum. It was collected by Prof. T.
D. A. Cockerell, in honor of whom the species is named, in Cottonwood
Gulch, on the west slope of the Sangre de Christo Range, in the Hudsonian
Zone, in Saguache County, Colorado, August 4, 1887.
There are also two specimens from Yellowstone Park in the collection
of Mr. F. P. Bowditch. The three show very little variation. I have never
seen any tendency to the formation of a basal band in H. spuria, although
I have seen many specimens in the Western States. This species has
apparently arisen discontinuously. The complete lack of intergrades I
have taken to indicate that it is intersterile with H. spuria, since complete
dominance, even if there be complete segregation, is not to be expected in
coccinellid color-patterns.
50
EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES.
3046 b. Hippodamia dispar Casey.
Distribution: Colorado.
Of this very rare species I have seen only the type in Major Casey's col-
lection, the specimen in the U. S. National Museum, and the one in the Leng
collection (fig. 34). The 3 specimens show some variation in the rotundity
of 4 + 5, but the combined spot is in all cases much rounded. The rounded
enlargement of the 44 5 area in H. cockerelli points strongly to a derivation
of H. dispar from H. cockerelli. A large series might reveal an amount of
intergradation which would bring them into one species. But at present
the few specimens known are distinct.
FIG. ;>•!.— Color-pattern of II. dispar from Colorado.
FIG. 3").— Variation of cl.vtral pattern in H. simiata. b — moilr; It to c, from ALumocla, California;
a, variety crotclii.
6049. Hippodamia sinuata Mulsant.
Mulsant's description seems to apply to the same beetles later named
H. trivittata by Major Casey, and his type came from the same locality.
This Californian species (see fig. 35), with the vittse complete, is, however,
distinct from the other beetles often called H. sinuata, which have the
vittae very strongly bowed in the apical half of the elytra, or incomplete
or lacking; these latter are properly placed in H. spuria.
Mr. Nunenmacher informs me that H. sinuata is restricted to the salt-
marshes, and in my collection in California I failed to find them outside of
the marshes. It is this fact, together with the lack of intergrades, that
causes me to consider them specifically distinct. This isolation by its
decrease of interbreeding would have afforded the opportunity to establish
intersterility.
Var. crotchi.
The suture black for only one-third of the length. One specimen from San Fran-
cisco in the collection of Mr. Leng.
3050. Hippodamia tredecimpunctata Linnaeus.
Distribution: Europe, United States, and Canada.
This species is the least variable of all the widely ranging species of
Hippodamia. Yet large series show variation (see figs. 36 to 38). This is
parallel in part to that given for Europe by Weise (1899) and Mulsant
(1846). The names and letters employed by them will be used. While
HIPPODAMIA.
51
some of these varieties as noted have not yet been found in America,
most of them are to be expected.
Var. padana Weise. Black pattern on pronotum small, less than twice the width of the
light margin (cf. fig. 37). Elytral spots small.
Var. signata Faldermann. Black pronotal pattern narrow. Elytra spotless. One from
Washington, but with mark £.
FIG. 36. — Variation in elytra! pattern in If.
6 = mode; a, from Washington; b, c, from Montana; (/, from
California; c, from Massachusetts; f, from iculix a,l>,
from Colorado. Variation of Color-pattern of head of //. par-
enthesis. c = mode; c, (I, from Stony Lake, Michigan; e, from
Toronto, Ontario.
FIG. 42.— Variation of pronotal pattern ol If.partnthesis. c — mode;
a to <; trom Dilley, Oregon; /to./, from atony Lake, Michigan.
54
EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES.
3051 a. Hippodamia apicalis Casey.
Distribution: Colorado to California, Arizona to Washington.
This species is closely allied to the the previous one (see fig. 43). It is
given specific rank because of its smaller size, darker pronotum, different
head and elytral pattern, and lack of intergrades. Since its range is within
that of H. parenthesis, which it does not displace, it can not be a subspecies
of it. In the following descriptions, a is a black mark along the suture at
and near the apex.
Typical pattern: Spots J+3, 1+2, 4+5+6+ a. (Fig. 43, e.)
Var. Spots J+3, 1+2, 6+4+5+6+ o inclosing alight spot. Arizona. (Fig. 43, h.)
Var. Spots J+3, 1+2+4+5+6+ a off. arctica Schneider. Nevada and Utah. (Fig.
43, flr.)
Var. Spots J+3, 1, 5, 4+6+a. Idaho. (Fig. 43, i.)
Var. Spots J+3, 1, 4, 5, 6+a. Colorado and Wyoming. (Fig. 43, c.)
Var. Spots J+3, 1, 4, 6+a. Colorado and Wyoming.
Var. Spots J+3, 5, 4+6, «. Colorado and Wyoming.
Var. Spots J+3, 1, 4, 6, a. Colorado and Wyoming.
Var. Spots J+3, 1, 4, a. Colorado and Wyoming.
Var. Spots J+3, 1, a. Colorado and Wyoming.
The pronotum is always much darker than in H. parenthesis, the caudal white spot
being especially reduced. The head has 2 spots near the cephalic border in-
stead-of 2 pyramids with their bases upon the border, as in H. parenthesis*
FIQ, 43.— Variation of elytral pattern in H. icalix. e =- mode; a, from California;
b, il, from Colorado; c from Wyoming; r,f, (/, from Nevada: h. from Arizona;
/, from Idaho.
Subspecies of Nevada and Utah: Spots never found missing and the vit-
tate variety frequent.
Subspecies of Colorado and Wyoming: The spots much reduced and some
frequently lacking.
Subspecies of Arizona: The black pattern much enlarged but not vittate.
A further development in this direction is seen in Southern California in
H. lengi.
Hippodamia apicalis is more closely allied to the European H. arctica and
the Siberian H. amoena than to H. parenthesis, and is, I believe, the Amer-
ican representative of H. arctica.
HIPPODAMIA. 55
3051 b. Hippodamia lengi, new species.
Distribution: Southern California.
In the Ulke collection in the Carnegie Museum at Pittsburg, Pennsyl-
vania, there are 8 beetles which aside from color-pattern resemble H.
apicalis. They are from California and bear a label ' Var. of H. paren-
thesis Horn dix. " There is one other of the same kind in the U. S.
National Museum from San Diego, California, and 'one from Southern Cal-
ifornia in the Horn collection of the Philadelphia Academy of Natural
Sciences. These 10 specimens are decidedly different in their color-pattern
from all specimens of H. parenthesis or apicalis that I have seen and should,
I believe, be recognized as a species, although it is to be considered as a
derivative of H. apicalis. I have designated one of the Pittsburg series
as the type.
The pronotum is more extensively pigmented than in H. parenthesis
or apicalis. In one specimen the mesocaudal light spot is wholly absent.
In the other cases it is small and triangular, with the point caudal. The
spots 4, 5, and 6 are confluent, sometimes leaving an inclosed light spot,
sometimes with the pigment continuous. The entire suture is pigmented
and confluent with the spots just mentioned. The pigment extends laterad
in the basal region to spots 1 and 3. The pigment generally involves the
base of the elytron, but in one case is free from it.
Var. A. The spot 3 free.
Var. B. The spots 1 and 3 free.
While the amount of confluence at the base of elytron is thus seen to be
variable, the distinctive feature of the species, the pigmented suture, is
constant. The species is named in honor of Mr. C. W. Leng, student of
this genus.
3052. Hippodamia faicigera Crotch.
Distribution: Hudson Bay, Great Slave Lake.
The specimens in the Horn and Leconte collections, in addition to their
lack of discal spots and to the more elongate elytra, have a lateral margin
which is straight or even slightly concave for a short distance. The vittse
are much less sinuate in the apical region than those of H. sinuata (see
fig. 7). A large series will throw light upon its relationships. For the
present we must conclude that it has probably developed along an inde-
pendent line rather than from H. sinuata.
56
EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES.
TRIBE COCCINELLINI.
Genus NEOHARMONIA Casey.
3055 a. Neoharmonia venusta Mulsant (fig. 44).
Distribution : Indiana to Kansas, Michigan to Texas.
Var. A Mulsant. The humeral spot united to the lateral spot of the intermediate row.
Var. B. As in fig. 44, 6.
Var. C. As in fig. 44, c. The pronotal spots confluent.
FIG. \\.-n to c, variation of color-pattern of N. venustn.
c, from Louisiana; d, e, N. notultitn.
3055 b. Neoharmonia notulata Mulsant (fig. 44).
Distribution: Louisiana.
Unfortunately I am unable to throw light on the interesting question
of the nature of this melanic derivative of the previous species. It is here
given specific rank with the greatest hesitancy.
Typical pattern as in fig. 44, d.
Var. C Mulsant. With the light mark reduced and divided into two smaller ones. The
lateral one may not reach the margin.
Var. D. As in fig. 44, e.
3055 c. Neoharmonia ampla Mulsant.
Distribution: Texas and Mexico.
The pronotal marks fused to make 2 longitudinal vittae (fig. 45).
The elytral pattern (fig. 46) is much reduced, revealing in some speci-
mens 4 separate SDots instead of 2 in the intermediate row and 4 separate
a
FIG. 45.— Variation in pronotal pattern of If. anipla. All from Brownsville, Texas.
FIG. 46— Variation in elytral pattern in JV. (i/nji/n. All from Brownsville, Texas.
spots instead of 2 in the apical row. This species stands intermediate in
elytral pattern between Neoharmonia venusta and Olla abdominalis and its
variation is parallel in general with the latter.
COCCINELLA.
57
1RIFASCIATA
TRICUSPIF
CALIFORNIA
TRANSVERSOGUTTATA
MONTICOLA
DIFFICILIS
Genus COCCINELLA Linnaeus.
The species of this genus recognized in the
United States are shown in fig. 47. Reference
to species outside of the United States is neces-
sarily omitted on account of the large size of the
genus. The species within the subgenera
are closely allied to each other, while
the subgenera are far less so.
3056 a. Coccinella perplexa Mulsant.
Distribution: North Europe,
Siberia, and North America.
Our American
species corre-
spond closely to
the Coccinella tri-
fasciata of Eu-
rope and Siberia.
It differs in hav-
ing the black area
of the pronotum
sharply reentrant,
in most cases, at
either side of the
mesal portion (fig.
48). It is given
specific rank with some hesi-
tancy. A comparison of a large
series of each would be desirable.
Var. eugenii Mulsant. Cephalic band broken
'(fig. 49).
Var. == Coccinella trifasciata var. fennica
Weise. Intermediate band broken.
Form A. Intermediate band only missing
(fig. 49, d).
Form B. Caudal band only missing (fig. 49, j).
Form C. Cephalic band broken and intermediate band
only missing (fig. 49, d).
Form D. Cephalic band broken and caudal band only
missing (fig. 49, w).
Var. Juliana Mulsant. Intermediate and caudal bands
missing (fig. 49, /). A specimen from Cypress
Hills, Long Island, was probably transported there
upon plants.
Form E. Intermediate and caudal bands missing,
cephalic broken (fig. 49, g.)
Form F. Intermediate band only present. Oregon
(fig. 49, o).
Var. subversa Leconte. Elytra without pigment. Pacific States (fig. 49, h).
Form G. Black area of pronotum extends to the cephalic edge broadly as in Coc-
cinella monticola. Rare. One from Berkeley, California (fig. 49 rf).,
SUTUFWU3
PROLONGATA
NOVEM-NOTATA
JOHNSONI
FIG. 47. — The species of Coccinelltt
in the United States.
58 EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES.
A series collected at random in the botanic garden of the University of
California, Berkeley, gave—
Var. subversa .............. . ............... ...................................... 1
Var. eugenii ........................................................................ 7
Var. eugenii transition to var. Juliana ................................ 8
Var. Juliana ....................................................................... 78
Var. Juliana, transition to Form C ...................................... 6
Form B .............................................................................. 5
Form A ............................................................................. 1
Var. Juliana transition to var. perplexa ............................. 2
Typical .............................................................................. 2
Large numbers show that the variety eucjenii is not as markedly set off
from the variety Juliana as has been stated. This is indicated by the
intergrades noted above.
a
d
Flu. 48. — Variation in pronotal pattern in C.
&=mode.
The relationship to C. novemnotata suggested by Mulsant is not close,
for the larvas offer a sharp contrast in color. The very closely allied
European species C. trifasciata shows only one recorded variety (variety
fennica) in which the intermediate band is broken. This variety was
seen only once in one of the heredity experiments referred to later. In
eastern North America C. perplexa is remarkably constant, but in the
West it becomes more and more variable, always, however, in the direc-
tion of reduction of pigment.
Subspecies of Oregon characterized by the presence of variety subversa
andF.
Subspecies of California characterized by the presence of Juliana.
Subspecies of Eastern States: The three bands seldom suffer reduction.
Two mated females kindly sent me by Professor Terhune, from Lon-
don, Ontario, gave me two fraternities. In one of these all 11 individuals
were normal like the parent. In the other fraternity 1 of the 3 individ-
uals corresponded to the variety fennica of C. trifasciata which I have not
seen in C. perplexa.
COCCINELLA.
59
3062. Coccinella tricuspis Kirby.
Distribution: Canada and neighboring States.
The elytral pattern of this species is so unique that its relationship is
puzzling (fig. 47). The few specimens known show no sU nificant varia-
tion.
3058. Coccinella novemnotata Herbst.
Distribution: North America.
Var. spots H-\-L, conjuncta Fitch. 4
per cent at Cold Spring Harbor
(see fig. 52).
Var. spots H-\-I.
Var. spots I-\-A.
Var. spots &+/. Seen on one side only
of 1 specimen from Oyster Bay,
Long Island.
Var. spots L+H+7.
Var. spots L -\-H -\-I-\- A, confluentn
Fitch.
Var. dirisicollis Fitch. Black pattern
of pronotum touching the cephalic
margin caudad to the eyes, but
not mesad. Known only from
Fitch's description. The prono-
tum is in general relatively con-
stant (fig. 50).
Var. degener Casey. The pigment re-
duced, the apical spot being re-
solved into two (fig. 51). Prob-
ably the specimens of C. mene-
triesi Mulsant, attributed to Cali-
fornia, are of this variety. But
as Crotch believes that C. mene-
triesi is a variety of C. undecim-
punctata, the relation of that
species to C. novemnotata requires
further study.
Form A. Some spots lacking.
Var. jranciscana Mulsant.
without spots.
Elytra
FIG. 49.— Variation of elytral pattern in C.
Subspecies of the Plateau States: Variety degener prevails.
Subspecies oj the Pacific Coast: Varieties degener and franciscana prevail.
60
EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES-
MODIFICATION AND HEREDITY.
The application of 40° C. to the prepupae and pupae did not affect the
pattern. The results of the experiments in heredity with this species are
summarized in table 17. Since on Long Island the variety conjuncta was
present in a ratio of 4 per cent, and each of
the other varieties was found in less than 0.1
per cent, the mates of females from nature
were probably normal. The progeny of such
a female (278) are represented in fig. 52. They
are remarkable, since 40 per cent of the prog-
eny surpass the unusually pigmented mother in the amount of confluence
of spots. It is hard to believe that this is;not determinate. The lack of
intergrades between the 4 normal specimens and those like the mother is
striking, especially in comparison with the experiment of 440 ?, and with
the presence of such intergrades in nature. In general, the conclusion is
TABLE 17.— Heredity in Coccinella novemnotata.
FIG. 50.— Variation in proimtal
pattern in CoccineUn not'eiimo-
tata. 6= mode.
Father.
Mother.
No.
Nor.
h+l
htr.l
h tr. /.
h tr. in
h+l,
h t r. m
ft f /-*-?))
No.
Elytral
pattern.
No.
Elytral
pattern.
278?
h+l+m
20
4
0
0 0
0
8
440 i
+ -
h+l
h tr. in
440 ?
h+l+m
55
23
3
0
0
1H
4
405 t
+ —
h+l
h tr. m
40j ?
nor.
46
39
.3
0
0
0
0
*449i
»i + a
'449 9
•in tr. i tr. /«
405?
nor.
46
0
0
0
0
0
2
*449?
;/i -j- (f 1 111 i
in tr. a
14
0
1
0
0
2
5
—
465 .
h a p. 1
ft ap. in
21
0
0
0
0
0
0
Total
159
8
1
4
1
3
7
f- 'Progeny of 405.
justified that there are here a number of positions of organic stability,
namely, h + l, /i+l-j-ra, m-(-a, /i + l + m+a; hi- m was never seen without
other confluence either in -these experiments or wild. In progeny from
465 9 (fig. 53) we see that an unusual shape of the humeral spot is inherit-
able. The amount and kind of intergradation varies in fraternities from
different parents, and from this we may infer that we are not dealing with
sharp-cut unit-characters, but rather with positions of organic stability
not finelv localized.
COCCINELLA.
61
3058 a. Coccinella johnsoni Casey.
Distribution: San Diego, California.
This species (fig. 47) is obviously a derivative of C. novemnotata.
Since C. novemnotata has the pronotal black free from the cephalic margin
throughout its range and throughout all of its variations from the lightest
variety, franciscana, to the darkest variety, confluenta (excepting the very
rare and peculiar variety divisicollis} , it is probably entitled to specific
rank. No typical specimen of the Western subspecies of C. novemnotata
has been collected in Southern California to my knowledge. A large series
is necessary to fix its status more definitely.
a
FIG. ol. — Variation of elytra! pattern of C. novemnvtntn in tlie Western State.*. /=mode.
96 °f.
40 %
FIG. 52. — Pedigree from 278 •;• .
3059. Coccinella transversoguttata Faldermann.
Distribution: Europe, Siberia, and North America.
Typical pattern: With a lateral spot. (See fig. 54, g.)
Var. quinquenotata Kirby. The lateral spot absent (fig. 54, d, e).
Var. nugatoria Mulsant. The basal band broken. Common in the Western States and
Mexico (fig. 54, c).
Form A. Lacking humeral spot (fig. 54, a). Very rare. Seen only in Eastern Wash-
ington. It is an extreme fluctuation of the reduction of pigment of the basal band
characteristic of that'region.
62
EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES.
The typical pattern is rare with us. Nearly all of our specimens in
North America are of the variety quinquenotata. The variety nugatoria
is common in the Western States, but not in the Eastern. Mulsant states
that it is found more often in the south of Europe than in the north.
Further knowledge of this distribution would be desirable. The extreme
of pigment reduction shown is the form A from Washington. This is in
good accord with the general belief that C. californica is a spotless deri-
vative of C. transversoguttata and favors the idea of their close relation-
ship. The variation in the pronotum is shown in fig. 55.
e f 9 h
FIG. 53.— Offspring of 405 ?.
n>
'•'
I [<;. ~>l. — Variation ot'elytral pattern off. transversoffut/ala. tor, from
Kamloops, British Columbia; /, fromStony Lake, Michigan; «/. I'roni \Vollaston. Massachusetts.
3059 a. Coccinella californica Mannerheim.
Distribution: Pacific States.
The small, yellowish basal area near the scutellar spot is present in
greater or less degree, the variation being continuous. The suture is pig-
mented ordinarily in California (see fig. 56), but in some cases approaches
variety nevadica.
Var. nevadica Casey.
The suture not pigmented back of the scutellar mark. Reno, Nevada.
Var. melanocollis n. var.
Pronotum entirely black (fig. 57) ; 2 specimens from Berkeley.
Two round white spots on the head found in this species and C. trans-
versoguttata make it not unlikely that it is a derivative of that species.
Unfortunately I was not able to make this cross. C. californica males
were mated with both C. monticola and nouemnotata and found to be
intersterile.
COCCINELLA.
63
3060. Coccinella monticola Mulsant.
Distribution: New England to the Pacific.
In degree of confluence of the elytral spots Coccinella monticola (fig.
58) gives the following varieties which have pronota as shown in fig. 59:
Var. sellica n. var. \ f median band. Califor-
nia and New Hampshire. (Fig. 58, d. )
Var. postwa n. var. Median band -(- apical band.
California. (Fig. 58, c.)
Var. conftuenta n. var. \ - median band -f api-
cal band. California. (Fig. 58, e).
Fl(;- 55. -Variation ..r pron..i:li pattern in
C. transversoguttata. Mode atob.
The following patterns (fig. 60), although they appear at first glance
very different from variety monticola, are nevertheless placed here, with
some reservation, because of the intergradation from C. monticola in the
direction of reduction of pigment in some localities. In any one locality
the amount of pigment is tolerably constant. It seems to me probable
that this amount in C. monticola is a result of environmental influence.
The variation in their pronota is given in fig. 61.
FI(T. oli. — Variation ol' elytra I patt'Tii of C. <'rni<'- mode.
FIG. 57.— Variation in pronotal pattern in C. ntfifornicft. l> mode; ,•/, variety iiie/nii»cii//in .
FIG. oS.— Variation in elytral pattern in C. nmn/ico/n. b -mode.
FIG. 59.— Variation of pronotal pattern in C. mnntirvla. 6=mode.
Var. alutacea Casey. Pigment of median band so reduced as to result in complete or
partial isolation of a lateral spot. Colorado and westward. (Fig. 60, e, d.)
Aberration impressa Casey. Similar, with "an impression along the side margin of the
pronotum extending arcuately inward just before the middle, disappearing from the
edge." This unique specimen is probably an aberration. The type specimen may
never be duplicated, or at least may not become established. California.
Var. sonorica Casey. The median band much reduced with the lateral spot absent.
Colonia Garcia, Chihuahua, Mexico. (Fig. 60, b.)
Var. bigiittata. Pigment much reduced. Lateral and apical spots absent. Buena Vista,
Colorado. (Fig. 60, a.)
64
EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES.
3061 a. Coccinella difficilis Crotch.
Distribution: Utah.
Although the pattern of this species (fig. 47) is very close to that of
C. monticola var. alutacea, it is probably entitled to specific rank. This is
because of its small size and the fact that the two elements of the median
row of elytral spots vary in the direction of greater pigmentation by
increase in general dimensions rather than by confluence. Specimens are
as yet too few to make its status and relationship clear.
ft-fr.
60
FIG. 60. — Variation of elytral pattern in C. monticola var. nliitacea and
FIG. 61.— Pronotal pattern of C. monticola var. nttttacen. n, n .single specimen.
3061 b. Coccinella suturalis Casey.
Distribution: Colorado.
This is very clearly a derivative from C. monticola var. alutacea by the
addition of the pigmented suture— a repertoire variation. Its specific rank
rests largely upon the reduced height of the elytra.
FIG. li.!. — Variation in color-pattern in C1. protonr/nta.
it, b, c, from Cheney, Wash.; rf, from Utah.
3061. Coccinella prolongata Crotch.
Distribution: Kansas to Pacific Coast.
The elytral pattern is essentially that of C. monticola var. alutacea,
from which it is probably derived, but with the pigment still further
reduced. The pronotal pattern is striking, and although there is some in-
tergradation, it is apparently interrupted (fig. 62). The essential char-
acteristic is not only the prolongation of the white area of the pronotum,
but the spindle shape of the central portion of the back area cephalad as
well as caudad. Its nearest allies have the black pattern extending along
the cephalic edge for half its width.
CYCLONEDA.
65
Genus CYCLONEDA Crotch.
The color pattern and its lines of variation in this genus are markedly
different from Coccinella, of which Leng makes it a subgenus. The form,
agility, and the difference of the food of the larvae (Johnson, 1907) sup-
port the generic distinction. The sexual difference alleged to exist in the
pronotal pattern, though noticeable, is much less than indicated by Mulsant
and Dimmock.
3064. Cycloneda sanguinea Linnaeus.
Distribution: Cuba, Bahamas, Florida to California.
Var. immaciilata Fabricius. With pale spots on pronotum inclosed. Florida to Louisiana-
The sexual differences in the median emargination of the black pronotal
area is either absent or slight.
a
FIG. 63.— Variation in pronotal pattern of Cyclonrdit
male, n. It, from Cold Sprint? Harbor, New York; <: icta. , from Palmetz,
Arizona; c, from Whitefish Point, Lake Superior; ii.<-itlvin duode<-iiiinin<-ui,it«: rf -mode; a, from Oregon: i>,
from Hudson Bay. .Inixucn/rin quatuordedmffuttata: h=modc; << , , from Montana; <-, from Mai'
quette, Michigan; /, from Catskill Mountains; , from Canada; li,j, /,-, n, from British Columl.ia;
(', from Hudson Bay; /, from Massachusetts; in, from Hood River, Oregon.
30T1. Anisocalvia quatuordecimguttata Linnaeus.
Distribution: Northern United States and Canada.
There is in the Museum of Comparative Zoology a very large series of
the beetles of this species, or at least of this genus, collected by Mr. H E.
Morse, at Lake Champlain. At the time of my visit to the museum they
could not be found. Until this much-needed series can be carefully
studied a revision of this genus is inadvisable. All the patterns are there-
fore given in fig. 79, with no attempt to define their status. Some are
said to exist in one sex only, but this requires investigation.
74
EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES.
Genus ANATIS Mulsant.
30?5. Anatis quindecimpunctata Oliv.
Distribution: Northeastern United States and Canada.
The dark form mentioned by Leng may well be an age difference, so
much does appearance change in specimens when kept alive. There is,
however, variation of spots (figs. 80 and 81 ) .
Form A. Inner apical spot absent.
Form B. Scutellar and subsutural intermediate spots confluent.
d
FIG. SO.— Variation in pronntal pattern in Anntix quindecimpunctata. /<=rnode. All from Stony Lake,
Michigan.
FIG. 81. — Variation of elytral pattern of A nntis mail and quindecimpunctata. and 0 in Epilachna b<>i-<-i/nchnii horeii/ix exposed to 40° C.
FIG. 8t). — £,j>ilii<-lin(i foiri'H. n, comparative
outlines of elytra from the side: solid line,
K. Itnrrri; dotted line, E h/irenUx; l>, color-
pattern of pronotum and elytra.
80
EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES.
hb
FIG. 9(1.— Varieties of //(/""'"""" <">">>•<»*, arranged to show the lack of straight lines of divergence.
PART III.
GENERAL DISCUSSION.
VARIATION.
The variation in the color-pattern of these beetles is so great that the
first impression is that it would be useless for taxonomic purposes. Some
entomologists have on this ground ventured to say arbitrarily that color
differences alone shall be an inadequate specific distinction. While this
practice has the warrant that where only a color difference is found, the
distinction is generally in fact varietal, such a discrimination against color
is of course untenable when the two forms are a distinct unit which do
not interbreed. On the other hand, Major Casey considers the color dif-
ferences in this family of such taxonomic value that he has created many
species thereon which others believe must be ranked as forms or varieties.
After an acquaintance with these beetles in large numbers, the varia-
tions are seen to have very different values. A considerable addition or
loss of pigment at some places on the elytra or pronotum will be recog-
nized as a mere fluctuation common throughout the range, whereas a very
small amount of pigment at another point would show it to be a separate
variety or even a distinct species. To the experienced coleopterist this is
a commonplace, but the neglect of it by the Wallace-Weismann school of
selectionists makes it worthy of note.
In general, the mere amount of pigment has the least significance. If
this pigment is not evenly added to the spots, it becomes more significant.
But if it is along the set lines for that species, it is of comparatively slight
consequence. It is when it breaks out from the set lines to appear at a
different point or to extend in new directions that the systematist may lay
stress upon it.
That the variation is determinate is shown in many ways. By determi-
nate variation is here meant a progressive variation in some definite direc-
tion, originating within the germ-plasm either with or without external
influence, and gradually, by waves or by leaps. The progeny differ in the
long run from the parents in some one direction, instead of offering indif-
ferently plus( -f) and minus (— ) variations in all the old characteristics and
having new characteristics in all directions, as seems to be assumed by Wal-
lace and in the earlier writings of Weismann. I have not used the term
orthogenesis, as I think that it is generally used for determinate evolution
operating unswervingly and without divergence in one direction for a long
period. Eimer thus used it, contending that the longitudinal pattern steadily
and unfailingly develops into a transverse pattern. It is not impossible that
such phenomena exist, but the determinate variations here described can
not be so characterized. Diversity prevails. Determinate variation will
be working in several features at once, advancing now here and now
81
82
EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES.
there, in one direction or the reverse direction. In fig. 90 the variations
of Hippodamia convergens are arranged to show this. In fig. 11 they were
arranged merely to show the successive steps of the several lines of devel-
opment. There is no kinetic or progressive principle here at work causing
a general march. Rather, these beetles have a repertoire of development-
lines which are called into activity here and there as the environment sets
one or another into play. This repertoire variation is illustrated in table 20.
The one variation that has appeared most frequently is spotlessness. I
believe that this is because loss as such is an exigency to which determin-
ers in the germ-plasm are more subject in the long run than any other;
just as all kinds of machinery have this one frequent cause of disablement
in common, the loss of some part. This item in the repertoire of varia-
tions is, then, common to most characteristics and organisms. When an
organ is composed of many cooperating parts, such as an eye, this liability
to loss or deficiency of one or another feature of its make-up renders it
more liable to variations of defect than a characteristic which is simple in
TABLE 20. — Repertoire variation in the color-pattern of the Coccinellidaz.
[For key to table sec page 83.]
< it'HUS.
•d
•i.
0;
r~
CB
•
03
» ?*
'§ ^
n s vc rs c
nttiu'in-c.
.— t
'Sic
—
z-z
-'
7.
-d
— •*-•
03
I
1
i
?, I
H '
1
0
br
C
la
1
•'a
!Jb
2
3
4
Megilla
-
Cdainia
8a
!ia
13.8
2li.9
21.3
11.5
5.3
2.3
.9
3
.3
.4
.4
0.3
il
4
.3
.8 S.I 11.1
33.3
22.2
12.8
fl.9
3.2
1.4
.5
.7
.8
g
1.0
0.7
S
QQ
5
(i
.1
.7
.3
2.2
Ml
7 s
5.3
27 9
19.2
20.9
17.0
14.1
12.8
8.1
8.5
4.3
4.9
2.0
2.7
.9
1.2
1.3
1.7
1.7
3.2
2.0
4.3
2.2
4.8
2.6
5.3
1.7
6.4
1.1
1 ^ 7
.li
3.5
11. li
10.4
9.3
7.0
4.62.13
1.4
2.11
l.ii
7.0
9 :;
10.4
11.6
3.5
0.6
QQ
S
1.1 (i.l
5.3
4 S
4.3
3.2 1 7
1.22.7
4.9
8 5
12.8
17.0
19.2
5.3 1.00.3
^3
9
1.7
2.6
2.2
2.0
1.7 1.3
-92.0
4.3
8.1
14.1
27.9 7.812.2 .7
0.1
cc
ft
10
.7
1.0
.8
.8
.7
.5
1.4
3.2
6.S
12.8
22.233.3 11.13 1 .8 .3
Successive
11
12
.4
.1
A
.2
1
.3
.1
1
.1
1
.9
c
2
2.3
1.5
1 0
5.3
4.1
11.5
9.5
7.8
21.3
20 5
18.1
36.9
37.9
39.2
i:>, s
16.4
18.1
4.61.3
(i.22.1
7.82.9
.1
.6
1.0
0.1
.1
.2
0.1
.1
0.1-
0.1-
-Nmnlior reduced to
The evolution of varieties and subspecies is readily enough accomplished
in these beetles. But the passage of the variety or subspecies into a spe-
cies, that is, the acquisition of intersterility, seems much more difficult of
accomplishment. The hypothesis of Romanes, that it has arisen by the
endowment of certain individuals with mutual fertility but with interster-
ility with the rest of the species, seems to me extremely unlikely, as such
individuals would have very low fecundity from the slim chance of finding
their interfertile mates. Of course there are a few exceptions in cases of
particular causes of endogamy. A more probable hypothesis is that of
correlation of some genital or developmental feature with the varietal
features, so that they become sufficiently unlike to cause intersterility.
There is a partial intersterility of Hippodamia convergent var. caseyi with
102 EVOLUTION IN COLOR-PATTERN OF THE LADY-BEETLES.
the species, and since var. caseyi has arisen within the range of H.
convergens, this seems to be the most probable explanation, especially
since the color-pattern difference is correlated with a difference in size,
as shown in table 10.
Where isolation can be resorted to, an explanation is simple. Determin-
ate variation in the isolated groups has worked in different directions, so
that the reproductive organs or processes may have often become so diverse
as to make them intersterile if a breakdown of the isolation brings them
to the test. In this I would suggest we find a reason why great organic
differences in artificial varieties do not bring about intersterility, while
much slighter differences in nature do. In the latter case determinate
variation has had its opportunity; in the former it has not. In these
beetles, however, isolation can only rarely give this assistance.
SUMMARY OF CONCLUSIONS.
(1) Variation. — Both continuous and discontinuous variations are found
in the color-pattern of these beetles. Variations are also found disposed
around certain centers of variation in greater numbers. Yet these centers
lack the discreteness necessary to constitute them unit-characters.
(2) Modification. — The color-pattern is capable of modification by the
environment. Some modifications exist as hereditary characters also,
while others do not. Non-hereditary modifications are more controlled by
the structure than are the hereditary variations. The germ-plasm and the
soma are in some cases capable of parallel modification, thus producing an
apparent inheritance of somatogenic characters.
(3) Distribution.— The species overlap to a great extent. The varieties
occur with the typical species in a part of their range. Jordan's law is in
general not followed; hence the evolution is probably for the most part
not by the even flow of all the individuals in a region.
(4) Heredity. — Segregate (alternative) heredity is general, but it varies
by degrees from blending to a typical segregate heredity. Mendelian
interpretations meet with difficulties in most cases. It is probable that
we have preponderance (prepotency of characters) in some cases.
(5) Phytogeny.- -There does not seem to be adequate ground for postu-
lating a definite single pattern as the primitive one for the family. Eimer's
laws of pattern development are not applicable. Several congeries of vari-
eties or species of diverse patterns may be attributed to descent from a
spotted pattern.
(6) Evolution. —Natural selection, if at all active, is principally conserva-
tive of the spotted pattern. In spite of this, determinate variation, largely
actuated by the effect of the environment on the germ-plasm, and probably
preponderance as well, have accomplished marked evolution of the pattern
from this condition. Evolution proceeds by waves as well as by even flow
and bv mutation in different characteristics at different times.
BIBLIOGRAPHY.
BURGESS, A. F.
1898. An abnormal Coccinellid. U. S. Dept. of Agriculture, Div. of Ento. Bull 17,
n. s., pp. 59-61.
1903. Economic notes on the family Coccinellidae. U. S. Dept. of Agriculture,
Div. of Ento. Bull 40, n. s., pp. 25-32.
BUMPUS, H. C.
1899. The elimination of the unfit as illustrated by the introduced sparrow, /-V/.s-.srr
domesticiis. Biological lectures delivered at the Marine Biological Labora-
tory at Wood's Holl, in the summer sessions of 1897 and 1898, pp. 209-226.
CROTCH, G. R.
1873. Revision of the Coccinellidaa of the United States. Trans. Am. Ent. Soc.,
vol. 4, pp. 363-382.
1874. A revision of the Coleopterous family Coccinellidae, London.
COCKERELL, T. D. A.
1898. The zonal distribution of Coleoptera. Bull. 28, Agr. Exp. Sta., MesillaPark,
N. Mex.
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