
Dec, 29, 1870] 
NATURE 
165 

truth, that, unless such objects are properly mounted, it 
is worse than useless to exhibit them to the public at all. 
They should be taken down and stowed away in drawers, 
or preserved in any other way that may be convenient for 
scientific study. Left in their glass cases, they are much 
more likely to repel than to attract the ordinary observer, 
for whose benefit the exhibition is intended. 
Under such circumstances we cannot receive otherwise 
than with pleasure a treatise prepared with the view of 
teaching the true principles of the art of taxidermy and 
their proper application. The Royal Cabinet of Natural 
History at Stuttgart is well known to those who have 
visited it as one of the few institutions of this kind where 
real care and skill are exhibited in the mounting of the 
specimens, and no onecan be more fitted than its ener- 
getic “Arefarateur” to give instructions upon a subject 
of which he has shown such perfect knowledge. Herr 
Martin has, moreover, obtained the assistance of several 
individuals who are fully qualified to assist him in his 
task, which appears to have somewhat of a comprehensive 
scope. Ina former part of the present work, Herr Martin 
has treated of the various methods of collecting animals of 
all sorts in the field, and of preserving them for scientific 
purposes. The fact of a third edition of this former 
part having been already called for shows that the work 
has been appreciated by those or whose instruction it 
is designed. In the present section of his volume, Mr. 
Martin and his fellow-workers treat more especially of 
the processes to be performed in the museum itself, 
such as the modelling in plaster of beasts large and 
small, the formation of preparations of the internal 
organs, the making of skeletons, and the mounting of 
microscopical objects. Full instructions are likewise 
given upon every point connected with the practical 
working of a public museum, not only as regard the 
objects themselves, and the best mode of exhibiting 
them, but also in relation to the wants and requirements 
of the visitors that resort to such institutions. 
ieee ate 


LIFATERS TO THE EDITOR 
[The Editor does not hold himself responsible for opinions expressed 
by his Correspondents. «No notice is taken of anonymous 
communications. | 
Mimicry versus Hybridity 
BEFORE attempting to combat the old theory under which Mr. 
Murray has taken refuge, in opposition to the theory propounded 
by Mr. Bates, I must first make afew remarks upon the different 
forms of mimicry to which the Lepidoptera are subject. 
Mimicry may be divided into two heads, viz. :—the mimicry 
of one lepidopterous insect by another, and the mimicry of the 
vegetable kingdom, and of backgrounds generally, by Lepidoptera. 
As Mr. Murray doubtless refers to only the first of these heads 
when he speaks of hybridisation, I need not trouble the reader 
with any remarks respecting the second. Mimicry, then, between 
butterflies and moths, may again be divided into three sections : 
that which modifies both sexes, that which chiefly modifies the 
females, and, lastly, that which chiefly modifies the males ;* 
these variations of modification are all easily explained by the 
theory of protective assimilation variously adapted to the economy 
of the different modified species ; but it can in no way be ex- 
plained by the theory of modification by hybridity. Mr. Murray 
speaks of hybridisation as if it were a thing recognised by lepi- 
dopterists, and of no uncommon occurrence, whereas it has, so 
far as I know, only occurred in the Heterocerous Lepidoptera, 
and only between species of the same genus; there is, indeed, 
a case on record of a skipper butterfly and a burnet moth being 
taken iz coitu, but no reasonable being could expect that any 
issue would result from suchan union ; again, I maintain that if 
it were even possible for hybridity to occur between different sub- 
* An interesting illustration of this type of mimicry exists between the 
genera Belenois and Mylothris, the males of the African group of Mylothris 
being identical in colour with males ofthe genus Belenois (sub-family Peirinz). 

orders, families, or even genera of Lepidoptera (which, by the 
way, is as likely as hybridity between a vulture and a dove or 
a horse and a rabbit), the offspring would inevitably be modified 
in structure just as much as hybrids between distinct races or 
species of vertebrates are ; they would moreover, if fertile, cer- 
tainly revert to one or other of the parent stocks, which, how- 
ever we do not find to be the case; if the fertilisation of flowers 
and butterflies were the same, hybrids might be as common in 
the one case as the other, and the results attained might be more 
nearly alike ; but as butterflies are not fertilised through the 
transmission of pollen by external agencies, and as they seem to 
have a decided preference for mates belonging to their own 
peculiar species, hybridisation must needs be a thing almost un- 
known amongst them. Lastly, I need scarcely say that the fact 
of birds hunting by sight and not by smell only does not in any 
way destroy the argument respecting the favoured and non- 
favoured species of Lepidoptera ; the same thing may be said of 
lizards, frogs, dragon-flies, and spiders, which all of them per- 
secute the order, and which all avoid not those insects only which 
have a peculiar odour, but those which, like the Danaine, Hel.- 
conine, Acerine, and others, have an acrid taste resulting from 
an offensive liquid which they exude from the body. I have been 
more fortunate than Mr, Scudder, inasmuch as I have frequently 
seen birds catch and devour the unprotected species upon the 
wing, whilst I have received abundant evidence both from 
scientific and non-scientific collectors respecting the perfect im- 
munity which the Davaime, &c., enjoy from all kinds of persecu- 
tion, whilst their less fortunate brethren come to an untimely 
end. * : 
British Museum ARTHUR G, BUTLER 
I AM rather surprise that Mr. Andrew Murray should Lave 
advanced his theory of mimicry being due to hybridisation, with- 
out adducing one solitary fact to prove that hybridisation be- 
tween distinct families of insects ever occurs, or that, if it do 
occur, the offspring are fertile izz/e se. Mimicry is most frequent 
between very distinct /w7ies or higher groups, and often be- 
tween different orders of insects. We may fairly consider that 
the “natural orders” of plants, as being the next well-marked 
groups above genera, are about equivalent to the families of 
insects, so that the analogy furnished by hybridisation among 
plants, on which alone Mr. Murray’s theory is founded, wholly 
breaks down, unless he can show (which he has not done) that 
such hybridisation occurs between species of different ‘‘ natural 
orders,” or of well-marked groups higherthan genera. It would 
be mere waste of time to discuss the details of a theory whose 
fundamental assumption is not only quite unsupported by fact, 
but is diametrically opposed to the almost, if not quite, universal 
fact that hybrids do not occur betweenspecies of different families 
or higher groups. 
Mr. Scudder’s letter contains some interesting and suggestive 
facts, and opens up a new field of investigation as to the 
immunity of certain species, in their egg or larva state, from the 
attacks of hymenopterous and dipterous parasites. It is, I be- 
lieve, now stated for the first time, that the peculiar secretions 
which render the Danaidze distasteful to birds not only extend to 
their larva and egg state, but act asa safeguard from the attacks 
of parasites. The objection that it would have been more 
advantageous for the larva than for the imago of the Zimenitis 
misippus to mimic the Danars archippus, appears to me to have 
no weight. We do not know, for instance, if such mimicry 
would be any defence against parasites who may be guided by 
smell rather than sight; and from the frequent limitation of 
certain odours and secretions to whole genera or families, the 
variations necessary to produce them may be of rare occurrence. 
The fact that Limenitis misippus and LZ. ursuéa are about 
equally plentiful is not at all remarkable, since there are species 
of all degrees of rarity in every extensive group ; but in this case 
it happens that both insects are mimickers, Limenitis ursala 
resembling the common N. American Pafilio philenor, especially 
on the under side, which is exposed when the insects are at rest. 
This case of mimicry is not so perfect or so striking as the other, 
but that it is one is pretty certain, and there are several other 
* The Hon. Mr. Justice Newton, who assiduously collected and took 
notes upon the Lepidoptera of Bombay, informed me that the Charaxes 
Psaphon of Westwood was continually persecuted by the bulbul, so that he 
rarely captured a specimen of this species which had not a piece snipped out 
of the hind wings ; he offered one to a bulbul which he had in a cage, and 
it was greedily devoured, whilst it was only by repeated persecution that he 
succeeded in inducing the bird to touch a Daxais, which he offered to it. 
