JuLy 6, 1899] 
cases Bates could only suggest—and Wallace at first 
accepted the suggestion—that the likeness was produced 
by some unknown influence connected with locality. In 
some mysterious way the species were supposed to be 
made alike as a direct result of life in a common district. 
No further advance was made until 1879, when Fritz 
Miiller suggested (Aosvzos, May 1879, p. 100) that the 
resemblance between relatively unpalatable forms was 
advantageous in facilitating the education of their young 
and inexperienced enemies, thus preserving a large pro- 
portion of the individuals which would have been 
necessarily sacrificed if the “warning” pattern of each 
species were different from that of every other in the 
same locality. Prof. Meldola translated this paper (Proc. 
Ent. Soc., Lond., 1879, p. xx.) and argued in favour of 
the explanation which Wallace also accepted. The same 
kind of likeness between specially protected forms was 
shown to exist in the tropical East by F. Moore (Proc. 
. Zool. Soc., 1883), and in Africa by the present writer 
(Report Brit. Association, 1897, p. 688). 
The hypothesis associated with the name of H. W. 
Bates was believed by a large number of naturalists from 
the very first, while that due to Fritz Miller was a long 
time in making its way. Of recent years, however, it 
has come to the front, chiefly in consequence of the 
papers of F. A. Dixey (Zvans. Ent. Soc., Lond., 1894, 
1896, 1897). In these papers Dixey has shown strong 
reasons for the belief that many examples formerly 
explained by the theory of Bates are in reality to be 
interpreted by that of Fritz Miiller. The wonderful 
tropical American groups of remotely allied species 
with a common appearance, selected by W. F. H. 
Blandford, assisted by the late Osbert Salvin, from the 
great Godman-Salvin collection, and exhibited at the 
Royal Society (1896) and Entomological Society (1897), 
also tended to deepen the impression which the 
Miillerian theory was making. It was clear to every one 
who examined the various groups (lists of the species 
exhibited are given in Proc. Ent. Soc., Lond., 1897) that 
the vast majority of the likenesses were between species 
which are known to be abundant and believed to be 
relatively unpalatable. 
The great interest and value of Mr. Sykes’ paper is 
given by the eight excellent plates which accompany it, 
reproducing many examples of Miillerian mimicry, and 
large numbers which are believed by the author and 
many others also to be still explicable by the theory of 
Bates. Their full discussion, as far as the facts at present 
known will allow, would be of great interest and would, 
in the opinion of the present writer, lead to the conclusion 
that a considerable proportion, at least, are more probably 
to be explained on Miillerian lines. The examples in 
the first two plates are almost without exception admitted 
to fall under the Miillerian theory, and they are de- 
scribed as “ Mutual Protective Resemblance of Inedible 
Butterflies.” All the examples are selected from tropical 
America, and supply a permanent record of many of the 
members of the groups selected by Blandford. 
Plate II. is here reproduced, and will serve well to show 
the closeness of the likeness which is attained, as well as 
the composite nature of the groups. That containing 
Figures 6 to Io is the most interesting in this respect, con- 
taining as it does representatives from three distinct sub- 
families, all of which are believed to be unpalatable—the 
Danainae, Ithomtinae and Heliconinae. A few errors 
which have crept into the description of the figures have 
been set right in the present reprint. (Fig. 6 is that of 
Fleliconius telchinia, not of Eueides zorcaon ; Eresia, Fig. 
15, belongs to the Mymphalinae, not the Pzerinae.) The 
distinction between the /¢homzinag and Danainae is now 
generally recognised, and has been introduced. A few 
of the species, viz. those named in Figs. 3, 4, 11, 14, 15, 
19, and 20, are insufficiently represented or altogether 
absent from the collection with which the plate has 
NO. 1549, VOL. 6c] 
NATURE 
222 
been compared. Hence the present writer cannot feel 
confident that these identifications are correct. 
In the third plate the well-known resemblance be- 
tween the three forms of female of Wypolimnas misippus 
(Nymphalinae), with its very different male, and the three 
forms of Lzmnas chrysippus (Danainae) are well shown 
by many examples ; but the author has fallen into the 
error which has often been made before (among others 
by the present writer), of stating (p. 61) that the forms 
completely correspond in the various parts of their 
range. The following statement is, it is believed, all 
that we are justified in making. In the tropical East 
(India, &c.), Lzmnas chrysippus is rarely represented by 
any but the typical forms, with amber ground colour, 
paler than in Africa, and black and white tip to the fore- 
wings ; the form with white hind-wings (alcipfozdes) is 
rare, and that without the black and white tip (4ugzz) 
much rarer still. On the other hand, the two latter forms 
of the mimicing female are not uncommon, especially 
the latter. At Aden all three forms of both model and 
mimic occur together commonly. In North-east Africa 
the chief forms of the Danaine are the normal and the 
klugtz, the white-winged form also occurring more 
rarely. In Somaliland the 4/wgcz form seems to pre- 
dominate ; out of several dozen specimens presented to 
the Oxford Museum by Mr. C. V. A. Peel, and captured 
in two visits, not a single form except £/g77 is present. 
The few female 4. mmzstfpus, on the other hand, are 
normal, and so a marked want of correspondence is re- 
vealed. Passing down the east of Africa to the south, 
klugit, at first abundant, becomes gradually rarer, until in 
the south it is extremely rare. In the female mzzszppus, 
on the other hand, the form zzaria, resembling £lugz?, is 
commonly intermingled with the typical form right down 
to the south. The white-hind-winged form of both 
model and mimic have a more parallel development 
occurring not uncommonly in both species. In tropical 
West Africa, on the contrary, the Danaine butterfly 
is always white-hind-winged, and the size of the white 
area is large (constituting true alc#fpus), while the 
very few females of A. mistppus which I have seen 
from this part of the world were normal. Much more 
evidence is required before the relationship can be 
made out for all parts of the extremely wide range which 
these two species have in common. I have here set 
down the conclusions which seem to be warranted by the 
facts at present known, in the hope that others may be 
induced to publish, or at least to make their observations 
known to the present writer. 
To summarise the facts set forth above, the varieties. or 
Limnas chrysippus are more definitely restricted to 
certain localities than those of the female Yyfolémnas, 
which is in all localities apt to be a more variable insect ; 
furthermore, intermediate forms between the varieties 
are commoner in the latter than in the former. In the 
case of those localities where there is a marked restriction 
of the forms of chrysifpus (Somaliland and tropical 
West Africa), there is no evidence of any equal restriction 
of the varieties of its mimic. 
The figure of a white-hind-winged a/cippus-like female 
Hypolimnas from Sierra Leone (Fig. 8) appears to have 
been taken from a not very perfect drawing, while all the 
other figures on all the plates are excellent reproductions 
from the specimens themselves. 
In the brief but useful memoir which accompanies 
these plates, the principles of mimicry are described, and 
many of the figured examples alluded to. In describing 
the distribution of the varieties of Liwnas chrysippus 
which has been here summarised, the author states that 
the uniformly coloured dorippus (k/ugiz) is supposed to 
be the ancestral form. The immensely predominant 
mimicry of the type form by butterflies and moths be- 
longing to all kinds of remotely allied groups, would, 
however, indicate with tolerable certainty that the type 
