INTRODUCTION. By Dr. A. Seitz. 
The boundary of the Indo-Australian Region towards the North-West, and North is more difficult 
to fix. The most southerly part of Persia, Beluchistan and the Punjab are still Indian, but form the border¬ 
lands, which join the districts of Kangra and Kulu in Southern Kashmir. But in Kashmir itself only the 
southern slopes of the Himalayas are still Indian; at the higher altitudes, and especially the localities which 
are more open towards the North, where the summer does not bring the terrible heat which in the 
neighbourhood of Lahore has turned the ground into a desert, Palaearctic forms occur in such numbers 
that the fauna is only connected with that of the adjoining district by a slight intermixture of Indian forms. 
Eastwards of this great northerly sweep in the neighbourhood of Kashmir, the Indo - Palaearctic 
boundary line suddenly recedes southwards. No Indian fauna can endure the ice-cold snowy winters of 
Tibet. Anything that can enjoy the sultry valleys of the Lower Indus and Ganges must succomb to the 
cutting wind of high-lying Tibet. Not till we approach Nepal, Sikkim and Bhutan do we get the double 
chains of protecting mountain ridges which give to the southernmost part of Tibet the character of a 
faunistic boundary-land. Then in the east of Tibet, where a still unexplored district crossed by mighty 
chains of mountains stretching north and south forms the watershed between the Mekong and Yang-tse- 
kiang Rivers, the natural boundary of the two faunistic regions may be placed. Then it follows the 
changeable Yang-tse Valley. Only where this gigantic river takes a wide sweep in southern Se-chuen 
towards Yun-nan, the boundary runs north of it, in the south of Ta-tsien-lu; then it follows, through the 
Chinese plain, the 30. degree of N. latitude. 
I have given considerable attention to the fixing of the Indo - Palaearctic boundary, which I have 
already set forth in detail in the introduction to the Palaearctic part. It is not a list of uncritically 
registered species of a district, or even the entirely valueless placing together of genera which depend on 
individual opinions, not being fixed entities, that gives us a definite clue as to the fauna to which a district 
belongs, but only the survey for faunistic purposes by trained eyes, preferably by personal observation. 
The casual appearance of a Melanitis leda does not prove that we are on Indo-Australian ground, but where 
it occurs commonly as a characteristic butterfly of the district, we can appeal to it as evidence that we 
are in the Indian faunistic Region. 
By personal observation I was able to convince myself that the question as to which faunistic 
region a place belongs to is by no means specially difficult to settle. In Shanghai the 10 commonest 
butterflies, arranged according to the frequency of their occurrence, are the respective local forms of the 
following species: 
Pieris napi, Colias liyale, Gonepteryx rhamni, Pyrameis cardui, Chrysoplianus plilaeas, Papi/io xuthus, 
Sericinus telamon, Lycaena baetica, Pieris melete, Parnara guttata. 
On Hong-Kong, lying only 10 degrees further south, not a single one of these species is specially 
common at any time of the year, Lycaena baetica and Pyrameis cardui alone being found there. The 
10 commonest Rhopalocera, likewise arranged according to their abundance (say about October), are the 
following: 
Terias hecab'e, Danais vulgaris, Euploea superba, Melanitis leda, Pieris canidia, Messaras erymauthis, Neptis 
eurynome, Mycalesis perseus, Catopsilia pomona, Hebomoia glaucippe. 
A large proportion of these species we have made acquaintance with in the 1. part of our work 
as observed in the Palaearctic Region, but never as characteristic butterflies; every one of these 
10 species is characteristic of their native places by their numerous, sometimes abundant occurrence. But 
only the commonest Lepidoptera of a district are of any use in settling disputed questions of zoogeo¬ 
graphy; as rarities they have, because exceptional appearances, sometimes only quite subordinate value, 
sometimes none at all. 
As also on the southern Japanese island the commonest butterflies are Lycaena argiolus, Chrysoplianus 
phlaea-s, Pieris napi , Ypthima argus, Pieris melete, Papilio machaon, etc., etc., this island is still absolutely and 
thoroughly Palaearctic, however many otherwise Indian Papilio may appear there as transient summer 
visitors; and in like manner the Lin Kiu island Okinawa with its Hestia, Danais, Hebomoia, Hypolimnas, etc., 
is thoroughly Indo-Australian. Thus the 30. degree of latitude divides the islands of the two faunistic 
regions in the Chinese Sea. 
In characterising the habitus of a fauna one has to consider the abundance in individuals much 
less than in the case of adducing geographical statistic differences. One gets a good idea of the habitus 
not only by observing the fauna in its native country, but also in examining a collection from there as 
complete as possible. It is the totality of the variations in form, colouring and pattern that admits of a 
survey and makes us acquainted with the most conspicuous peculiarities. We have already pointed out in 
the introduction to the American part of our work that in the Indian Region the gorgeous colouring of 
shining bands or spots, mostly yellow or metallic blue, on a deep black ground-colour, is far less common 
than in tropical America. The magnificent blue of Morpho, Prepona, Myscelia, Callicore, of many large 
Tkecla, etc., occurs very rarely in the Indian Region; but the ochrous colours, which sometimes predominate 
in India through whole extensive genera ( Cynthia, Cirrhochroa, Messaras, Charaxes, Clerome, etc., etc.,) are 
strongly developed. The hyaline species, so abundant in tropical America, such as the Ithomiids, Haetera , 
