INTRODUCTION. 
a danger that the identifications in such a paper are less precise than 
in “revisions” when the whole of the available material of one 
species, or group, is reviewed at one time. Having dealt with a 
common sunbird in a dozen papers in several years there is a chance 
of hasty, or perfunctory examination when the species again turns 
up in a small collection from an island, the avifauna of which it is 
desirable to list. 
I have, therefore, on the present occasion, surveyed anew all the 
material in Singapore; studied in detail much of the relevant material 
in the museums of London, Tring, Buitenzorg and Kuching; and 
examined a number of the more critical forms in hasty visits to the 
museums of Amsterdam, Leyden and Berlin. In the Raffles Museum, 
Singapore, there are now housed collections which, taken together, 
are probably the most representative of Malaysia in existence. Un- 
fortunately, I have not been able to visit the United States National 
Museum wherein are extensive Malaysian collections. 
In a number of cases, subspecies based on alleged colour 
distinctions have not been accepted. Some of this difference of 
opinion depends no doubt on the observer's eye; some of it on lack 
of agreement anent the criterion of separation for. it seems clear that 
some authors separate races when the extremes of series differ, but 
I susj>ect that most of it is due to lack of understanding of post- 
mortem changes in colour. Very little seems to be known of this 
subject, but I am convinced that skins kept in museums in the tropics 
even in the shelter of protected cabinets usually fade sooner than do 
those in museums in England. 
The rapidly fugitive colours of Cissa and the more slowly fading 
pigments of Harpactes are well-known, but almost as astonishing in 
their colour change are skins of some of the more brightly coloured 
timaliids such as Mesia and Siva. Less well-known are the receding 
reds of Aethopyga and the rapidity with which some small, dull- 
coloured timaliids and pycnonotids change colour after death. In 
these the olive element in the plumage soon disappears, the greyness 
fades away, the browns come up, deepen in colour, (“hum”) and 
then a general “snuffiness” pervades the skin. In a recent test 
case I found that some skins of Stachyris maculaius lost their, fresh- 
ness in a few months and altered considerably in three years. On 
the other hand, in 1930, X found that some skins of various species 
well-known to fade, collected by Whitehead in 18&B, were practically 
identical in tone with others taken personally in 1929, Little seems 
to be known about even the superficial causes of these post-mortem 
changes. Ignoring such drastic treatment as total immersion in 
spirit prior to skinning, I have noted that in some cases, tow and 
grass used as stuffing material have altered the colour of mammal 
skins. Drying over a wood fire will also produce queer results at 
times and relaxing and remaking not infrequently darkens a skin. 
Perhaps some post-mortem changes are due to physiological causes 
such as the age of the feather when the bird is collected. 
xix 
