Preface. 
It was three years ago that the first Volume of Heterocera — that of the African fauna — was 
published and today we are glad to announce the completion of the corresponding part of the Indo-Australian 
Lepidoptera. Simultaneously Supplementary Volume 2 of the palaearctic Sphinges and Bombyces and the 
final plates and concluding sheets of Volume 6 will be published, so that the third great epoch in the 
publication of the “Macrolepidoptera of the World" has been reached. The first stage was the 
completion of the entire Palaearctic Fauna (concluded in 1915). The second stage covered all the Exotic 
JRhopalocera (1927). And now we have completed the Exotic Sphingidae and Bombycidae, thus having dealt 
with all the species mentioned in F. Kirby's “Systematic Catalogue". 
This tenth Volume comprises 880 pages of text and 104 plates (numbered 1- TOO) covering the entire 
Indian region that lies southwards of the palaearctic boundary and as originally defined, including therefore 
Australia and all the numerous islands spread over that territory. Whilst this area is the largest of all. it 
by no means contains the richest fauna or the greatest number of species. Many of these islands, even such 
that are almost as large as Italy (as for instance New Zealand) show an extraordinary dearth in the species 
that are dealt with in Volume 10 (in New Zealand there are but 17), despite the fact that climatic condi¬ 
tions would appear to be favourable to their development. The scarcity of insect life shown in some of the 
regions dealt with in this Volume, is partially counterbalanced by a superabundance of species in other parts 
of the same territory (for instance the Himalayas and New Guinea). These districts are known to be among 
the richest in insect fauna in the whole world. It has however been possible to condense the whole essential 
material into one Volume and one that will, we hope, prove to be not too unwieldy. 
It will be realised that the matter handled in the 10th Volume can by no means be considered ex¬ 
haustive. The Indo-Australian archipelago, especially the Papuan territories provide new forms almost month 
by month, so that comprehensive supplementary Volumes will have to follow, until it can be declared that 
the Indo-Australian fauna has been thoroughly studied and classified. Whilst it cannot be asserted that the 
entire territory covered by this Volume, has been so little explored as that handled in Volume 14, nevertheless 
it is a fact that large districts have never yet been visited by expeditions or collectors. Practically the whole 
of the interior of Australia, as well as numerous of the Islands, have only been very superficially examined. 
British India and the cultivated areas of the Dutch East Indies have probably been the most thoroughly 
worked, but the countries bordering on same, have in many instances, as yet never been visited by scientists. 
Publications that are comprehensive and richly illustrated, only exist of very few districts of the Indo-Austra¬ 
lian region. There are of course a large number of excellent illustrations of the Bhopalocera of these districts 
and splendid preliminary work has been done by Sir George II ampson in regard to the Noctuidae in his 
masterly “Catalogue of Lepidoptera Phalaenae”, nevertheless thousands of Heterocera are being illustrated for 
the first time in the plates of this Volume. Barely one-third of some 320 Zygaenidae comprised on the first 
8 plates have ever been illustrated before. Very few of the Drepanidae (abt. 300) have ever been shown 
at all and the same may be said of the families of the TJiyrididae and Limacodidae. Not even one-third of 
the 500 Lymantriidae figured in this Volume has been illustrated in colour-print hitherto. Taken altogether this 
Volume contains 4500 illustrations and never vet have collectors been able to quickly diagnose, determine 
and classify their collections from such coloured illustrations. Most of these illustrations have been made 
