Dec. 7, 1882] 
NATURE 
125 
to expect a popular treatise on all orders of insects, an 
idea at once dissipated-by the title-page. There are 
other books covering the same ground that would answer 
the young student’s purpose as well as this. Judging 
it in comparison with the multitudinous other compila- 
tions from the same pen, we have no very particular fault 
to find. It is sketchy, but in some respects it compares 
favourably, especially in some of the explanations con- 
cerning the Co/eoftera. Some of the illustrations are 
good, others wretchedly bad, and unrecognisable without 
the explanations. When comparing the ‘“‘nervures” in 
the wings of a butterfly with the “rays” in the fins of a 
fish (p. 178), the writer should have explained the minute 
structure of both. 
The real point at issue in connection with books of this 
nature is their effect. ‘They are eminently rudimentary, 
and not elevating. Let us take instances from the 
book now under review. At p. 14, after an explanation 
of the terminology of the external skeleton of a beetle, 
we read :—“ At first some of these terms may appear to 
be harsh, repulsive, and difficult to master. In reality 
they are not so, and a knowledge of them is absolutely 
necessary to any one who wishes to understand the de- 
scription of an insect.” This is a very sensible remark. 
Yet throughout the book the utmost favour is bestowed 
upon absurd meaningless “ English’? names. The cul- 
minating point of absurdity is reached at p. 276. Amongst 
the small moths the author “figures” one (under a mis- 
spelt generic name), and because it (out of several hun- 
dred other fortunate little moths) has received no 
“ popular ” name, he terms it the “ Brown Dolly”! 
Anthropo-Geographie oder Grundziige der Anwendung 
der Erdkunde auf die Geschichte. Von Dr. Friedrich 
Ratzel. (Stuttgart : Englehorn, 1882.) 
WE have had occasion to speak of the wide extension 
which geographical science has taken in Germany, and of 
the broad and intricate field which it covers. The work 
before us is a good example of this. It is the first of a 
series of geographical handbooks, which is to include 
“General Geology,” by Prof. von Fritsch; “ Oceano- 
graphy,” by Dr. von Boguslawski; “ Geographical Dis- 
tribution of Animals,” by Prof. L. von Graff; “ Clima- 
tology,’ by Dr. Hann; “Glaciers,” by Prof. Heim; 
“Volcanoes and Earthquakes,” by Prof. von Fritsch ; 
and “ Botanical Geography,” by Dr. Oskar Drude, Dr. 
Ratzel’s volume must not be mistaken for a treatise 
on Anthropology. That subject it only incidentally 
includes, its main purpose being to point out in 
detail the light which geography sheds upon _his- 
tory and the development of social and political eco- 
nomy. The author discusses the various conceptions 
of geography, its place among the sciences, the human 
element in geography, and the relations between geo- 
graphy and history. After a brief introduction on these 
points, the author proceeds to consider, in the second 
part, natural conditions, and their influence on mankind, 
Under the head of position and aspect of the dwelling- 
places of man, pointing out the parts which continents, 
islands, and peninsulas have played in the distribution of 
the human species and in history, he devotes a chapter to 
states and the various conditions which determine their 
boundaries, and in another discusses the distribution of 
centres of population. In a chapter on conditions of 
space he discusses the subject of great and small 
states, and the connection between the extent and 
power of states, and has some spe tally interesting 
remarks on what he calls the continental type of history. 
In a section on surface-forms, the author treats of such 
subjects as the inequalities of the earth’s surface and of 
the contrast, ethnologically and historically, between 
mountainous and flat countries—of plains, steppes, and 
deserts. To the important subject of coast-lines, and the 
dependence of a country’s development on their form, a 
chapter is devoted, and two to the historical importance 
of water, in its various forms of sea, lakes, rivers, and 
marshes. Considerable space is, of course, given to 
climate and to the animal and plant world. One of the 
most interesting chapters is that on ‘“ Natur und Geist,” 
in which Dr. Ratzel attempts to show the great influence of 
a people’s surroundings on their mental and moral deve- 
lopment. In two concluding chapters the author gathers. 
up the lines of discussion, referring especially to the 
subject of human migration, its influence on history, and 
its effect on the mixture of races; and finally points out 
the practical bearings of his subject. Thus it will be seen 
that, whether the subject comes legitimately under the 
conception of geography or not, Dr. Ratzel has written a 
work of great interest and of much utility to the historian 
who wishes to treat history in a scientific spirit. It is 
both instructive and attractive reading. 
LETTERS LOVEE ED LROR 
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[The Editor urgently requests correspondents to keep their letters 
as short as possible. The pressure on his space is so great 
that it is impossible otherwise to ensure the appearance even 
of communications containing interesting and novel facts.\ 
Mimicry in Moths 
I OBSERVED here, a few days ago, a case of mimicry which 
interested me much, and may deserve mention. The weather 
has been such as is usual on this part of the Riviera at this 
season. There has been a very hot sun, with sometimes a very 
cold ‘‘ mistral’? wind. Insect life is a! undant, and not a few 
of our summer .5j/vdad@ seem to secure a very good living. Flies 
are a plague. Mosquitos are not wanting. Bees are busy, and 
large dragonflies hunt continually. But there is one order of 
insects ‘‘ccnspicuous by its absence,” and that is the Zefé- 
doptera. Neither the diurnal nor the nocturnal species have been 
visible. 
Iwas much surprised, therefore, one day last week to see a 
large insect of this order come from above the olive trees over- 
| head, with the wild dashing flight of the larger moths. Attracted 
| apparently by the sheltered and sunny recess in which I was 
sitting and by the scarlet geraniums and | ignonias which were in 
full flower in it, the moth darted downwards, and after a little 
hovering, settled suddenly on the bare ground underneath a 
geranium plant. I then saw that it was a very handsome syecies, 
with an elaborate pattern of light and dark chocolate browns. But 
the margins of the wings, which were deeply waved or dentated, 
had a lustrous yellow colour, like a brilliant vleam of light. In this. 
position the moth was a conspicuous object. After resting for a 
few seconds <pparently enjoying the sun, it seemed to notice 
some movement which gave it alarm. It then turned slightly 
round, gave.a violent jerk to its wings, and instantly became 
invisible. 1f it had subsided into a hole in the ground, it could 
not have more completely disappeared. As, however, my eyes 
were fixed upon the spot, I soon came to observe that all the 
interstices among the little clods around it were full of withered. 
and crumpled leaves of a deep blackish brown, I then further 
noticed that the spot where the moth had sat was apparently 
occupied by one of these, and it flashed upon me in a moment 
that I had before me one of the great wonders, and one of the 
great mysteries of nature. There are some forms of mimicry 
which are wholly independent of the animals themselves. They 
are made of the colour and of the shape which are like those of 
the surrounding objects of their habitat. They have nothing to. 
do except to sit still, or perhaps to crouch. but there are some 
other forms of mimicry in which the completeness of the decep- 
tion depends on some co-operation of the animal’s own will. 
This was one of these. The sple1.did margins of the fore-wings, 
with the peculiar shape and their shining colour had to be con- 
cealed ; and so, by an effort which evidently required the exer- 
tion of special uuscles, these margins were folded down— 
covered up—and hidden out of sight. ‘Ihe remainder of the 
wings were so crumpled up that they imitated exactly the dried 
and withered leaves around. 
