v COLOURS OF ANIMALS 345 
abundance ; the species with small and inconspicuous flowers 
greatly preponderate ; and the flowering season of each kind 
being of short duration, they rarely produce any marked 
effect of colour amid the vast masses of foliage which sur- 
round them. An experienced collector in the Eastern tropics 
once told me that although a single mountain in Java had 
produced three hundred species of Orchidex, only about 2 
per cent of the whole were sufficiently ornamental or showy 
to be worth sending home as a commercial speculation. The 
Alpine meadows and rock-slopes, the open plains of the Cape 
of Good Hope or of Australia, and the flower-prairies of 
North America, offer an amount and variety of floral colour 
which can certainly not be surpassed, even if it can be 
equalled, between the tropics. 
It appears, therefore, that we may dismiss the theory that’ 
the development of colour in nature is directly dependent on, 
and in any way proportioned to, the amount of solar heat and 
light, as entirely unsupported by facts. Strange to say, how- 
ever, there are some rare and little-known phenomena which 
prove that in exceptional cases light does directly affect the 
colours of natural objects, and it will be as well to consider 
these before passing on to other matters. 
Changes of Colour in Animals produced by Coloured Light 
A few years ago Mr. T. W. Wood called attention to the 
curious changes in the colour of the chrysalis of the small 
cabbage-butterfly (Pontia rape) when the caterpillars, just 
before their change, were confined in boxes lined with 
different tints. Thus in black boxes they were very dark, in 
white boxes nearly white ; and he further showed that similar 
changes occurred in a state of nature, chrysalises fixed against 
a whitewashed wall being nearly white, against a red brick 
wall reddish, against a pitched pailing nearly black. It has 
also been observed that the cocoon of the emperor-moth is 
either white or brown, according to the colours surrounding 
it. But the most extraordinary example of this kind of 
change is that furnished by the chrysalis of an African 
butterfly (Papilio Nireus), observed at the Cape by Mrs. 
Barber, and described (with a coloured plate) in the Transac- 
tions of the Entomological Society, 1874, p. 519. 
